RFC 4005
Diameter Network Access Server Application
RFC 4005: Diameter Network Access Server Application ✨
okay so let's start with the basics 🎀
- RFC number: 4005
- Title: Diameter Network Access Server Application
- Authors: P. Calhoun, G. Zorn (both Cisco Systems Inc.), D. Spence (Consultant), and D. Mitton (Circular Networks)
- Category: Standards Track
- Date: August 2005
- Obsoletes / Updates: none listed in the title block
Status of This Memo 📋
bestie, this part is the legal-ish bit, but it's short and sweet 💅 It says this is an Internet standards track protocol for the Internet community, and the authors are openly asking for discussion and suggestions for improvements 🫶 If you want the current standardization state of this protocol, you go check the "Internet Official Protocol Standards" (STD 1) document. And yes, distribution of this memo is unlimited, so share it with everyone 🌈
Copyright Notice ⚖️
Copyright (C) The Internet Society (2005).
Abstract 🦋
so the abstract is basically the elevator pitch ✨ This doc describes a Diameter protocol application for AAA (Authentication, Authorization, and Accounting) services in the Network Access Server (NAS) environment. When you pair it with the Diameter Base protocol, the Transport Profile, and the Extensible Authentication Protocol specs, this application covers the typical network access services requirements. it's giving complete package 💖
legacy systems are going to be part of the picture when Diameter first rolls out 🧚 so this application was carefully designed to make converting between RADIUS and Diameter way less painful 😭 The trick is that it includes the RADIUS attribute space, so you don't have to do a ton of attribute translations. literal genius 👑
last bit, and it's a big one 🔥 The interactions between Diameter applications and RADIUS that this document specifies are meant to apply to all Diameter applications. So in this sense, this document extends the Base Diameter protocol. main character energy 💜
Table of Contents 🗺️✨
okay bestie, this is the map for the whole doc 💖 every section, subsection, and appendix is listed here with its page number, so you can jump around like a pro 🦋
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . 5
1.2. Requirements Language . . . . . . . . . . . . . . . . . 6
1.3. Advertising Application Support . . . . . . . . . . . . 6
2. NAS Calls, Ports, and Sessions . . . . . . . . . . . . . . . . 6
2.1. Diameter Session Establishment . . . . . . . . . . . . . 7
2.2. Diameter Session Reauthentication or Reauthorization . . 7
2.3. Diameter Session Termination . . . . . . . . . . . . . . 8
3. NAS Messages . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1. AA-Request (AAR) Command . . . . . . . . . . . . . . . . 9
3.2. AA-Answer (AAA) Command . . . . . . . . . . . . . . . . 11
3.3. Re-Auth-Request (RAR) Command . . . . . . . . . . . . . 13
3.4. Re-Auth-Answer (RAA) Command . . . . . . . . . . . . . . 14
3.5. Session-Termination-Request (STR) Command . . . . . . . 15
3.6. Session-Termination-Answer (STA) Command . . . . . . . . 15
3.7. Abort-Session-Request (ASR) Command . . . . . . . . . . 16
3.8. Abort-Session-Answer (ASA) Command . . . . . . . . . . . 17
3.9. Accounting-Request (ACR) Command . . . . . . . . . . . . 17
3.10. Accounting-Answer (ACA) Command. . . . . . . . . . . . . 19
4. NAS Session AVPs . . . . . . . . . . . . . . . . . . . . . . . 20
4.1. Call and Session Information . . . . . . . . . . . . . . 21
4.2. NAS-Port AVP . . . . . . . . . . . . . . . . . . . . . . 22
4.3. NAS-Port-Id AVP . . . . . . . . . . . . . . . . . . . . 22
4.4. NAS-Port-Type AVP . . . . . . . . . . . . . . . . . . . 22
4.5. Called-Station-Id AVP . . . . . . . . . . . . . . . . . 23
4.6. Calling-Station-Id AVP . . . . . . . . . . . . . . . . . 23
4.7. Connect-Info AVP . . . . . . . . . . . . . . . . . . . . 24
4.8. Originating-Line-Info AVP . . . . . . . . . . . . . . . 24
4.9. Reply-Message AVP . . . . . . . . . . . . . . . . . . . 25
5. NAS Authentication AVPs . . . . . . . . . . . . . . . . . . . 26
5.1. User-Password AVP . . . . . . . . . . . . . . . . . . . 26
5.2. Password-Retry AVP . . . . . . . . . . . . . . . . . . . 27
5.3. Prompt AVP . . . . . . . . . . . . . . . . . . . . . . . 27
5.4. CHAP-Auth AVP . . . . . . . . . . . . . . . . . . . . . 27
5.5. CHAP-Algorithm AVP . . . . . . . . . . . . . . . . . . . 28
5.6. CHAP-Ident AVP . . . . . . . . . . . . . . . . . . . . . 28
5.7. CHAP-Response AVP . . . . . . . . . . . . . . . . . . . 28
5.8. CHAP-Challenge AVP . . . . . . . . . . . . . . . . . . . 28
5.9. ARAP-Password AVP . . . . . . . . . . . . . . . . . . . 28
5.10. ARAP-Challenge-Response AVP. . . . . . . . . . . . . . . 28
5.11. ARAP-Security AVP. . . . . . . . . . . . . . . . . . . . 29
5.12. ARAP-Security-Data AVP . . . . . . . . . . . . . . . . . 29
6. NAS Authorization AVPs . . . . . . . . . . . . . . . . . . . . 29
6.1. Service-Type AVP . . . . . . . . . . . . . . . . . . . . 30
6.2. Callback-Number AVP . . . . . . . . . . . . . . . . . . 32
6.3. Callback-Id AVP . . . . . . . . . . . . . . . . . . . . 32
6.4. Idle-Timeout AVP . . . . . . . . . . . . . . . . . . . . 32
6.5. Port-Limit AVP . . . . . . . . . . . . . . . . . . . . . 32
6.6. NAS-Filter-Rule AVP . . . . . . . . . . . . . . . . . . 32
6.7. Filter-Id AVP . . . . . . . . . . . . . . . . . . . . . 33
6.8. Configuration-Token AVP . . . . . . . . . . . . . . . . 33
6.9. QoS-Filter-Rule AVP . . . . . . . . . . . . . . . . . . 33
6.10. Framed Access Authorization AVPs . . . . . . . . . . . . 35
6.10.1. Framed-Protocol AVP . . . . . . . . . . . . . . 35
6.10.2. Framed-Routing AVP. . . . . . . . . . . . . . . 35
6.10.3. Framed-MTU AVP. . . . . . . . . . . . . . . . . 35
6.10.4. Framed-Compression AVP. . . . . . . . . . . . . 36
6.11. IP Access Authorization AVPs.. . . . . . . . . . . . . . 36
6.11.1. Framed-IP-Address AVP . . . . . . . . . . . . . 36
6.11.2. Framed-IP-Netmask AVP . . . . . . . . . . . . . 36
6.11.3. Framed-Route AVP. . . . . . . . . . . . . . . . 37
6.11.4. Framed-Pool AVP . . . . . . . . . . . . . . . . 37
6.11.5. Framed-Interface-Id AVP . . . . . . . . . . . . 37
6.11.6. Framed-IPv6-Prefix AVP. . . . . . . . . . . . . 38
6.11.7. Framed-IPv6-Route AVP . . . . . . . . . . . . . 38
6.11.8. Framed-IPv6-Pool AVP. . . . . . . . . . . . . . 38
6.12. IPX Access . . . . . . . . . . . . . . . . . . . . . . . 38
6.12.1. Framed-IPX-Network AVP. . . . . . . . . . . . . 39
6.13. AppleTalk Network Access . . . . . . . . . . . . . . . . 39
6.13.1. Framed-AppleTalk-Link AVP . . . . . . . . . . . 39
6.13.2. Framed-AppleTalk-Network AVP . . . . . . . . . 39
6.13.3. Framed-AppleTalk-Zone AVP . . . . . . . . . . . 40
6.14. AppleTalk Remote Access. . . . . . . . . . . . . . . . . 40
6.14.1. ARAP-Features AVP . . . . . . . . . . . . . . . 40
6.14.2. ARAP-Zone-Access AVP. . . . . . . . . . . . . . 40
6.15. Non-Framed Access Authorization AVPs . . . . . . . . . . 40
6.15.1. Login-IP-Host AVP . . . . . . . . . . . . . . . 40
6.15.2. Login-IPv6-Host AVP . . . . . . . . . . . . . . 41
6.15.3. Login-Service AVP . . . . . . . . . . . . . . . 41
6.16. TCP Services . . . . . . . . . . . . . . . . . . . . . . 42
6.16.1. Login-TCP-Port AVP . . . . . . . . . . . . . . 42
6.17. LAT Services . . . . . . . . . . . . . . . . . . . . . . 42
6.17.1. Login-LAT-Service AVP . . . . . . . . . . . . . 42
6.17.2. Login-LAT-Node AVP. . . . . . . . . . . . . . . 43
6.17.3. Login-LAT-Group AVP . . . . . . . . . . . . . . 43
6.17.4. Login-LAT-Port AVP. . . . . . . . . . . . . . . 43
7. NAS Tunneling . . . . . . . . . . . . . . . . . . . . . . . . 44
7.1. Tunneling AVP . . . . . . . . . . . . . . . . . . . . . 44
7.2. Tunnel-Type AVP . . . . . . . . . . . . . . . . . . . . 45
7.3. Tunnel-Medium-Type AVP . . . . . . . . . . . . . . . . . 46
7.4. Tunnel-Client-Endpoint AVP . . . . . . . . . . . . . . . 46
7.5. Tunnel-Server-Endpoint AVP . . . . . . . . . . . . . . . 47
7.6. Tunnel-Password AVP . . . . . . . . . . . . . . . . . . 48
7.7. Tunnel-Private-Group-Id AVP . . . . . . . . . . . . . . 48
7.8. Tunnel-Assignment-Id AVP . . . . . . . . . . . . . . . . 48
7.9. Tunnel-Preference AVP . . . . . . . . . . . . . . . . . 49
7.10. Tunnel-Client-Auth-Id AVP. . . . . . . . . . . . . . . . 50
7.11. Tunnel-Server-Auth-Id AVP. . . . . . . . . . . . . . . . 50
8. NAS Accounting . . . . . . . . . . . . . . . . . . . . . . . . 50
8.1. Accounting-Input-Octets AVP . . . . . . . . . . . . . . 51
8.2. Accounting-Output-Octets AVP . . . . . . . . . . . . . . 52
8.3. Accounting-Input-Packets AVP . . . . . . . . . . . . . . 52
8.4. Accounting-Output-Packets AVP . . . . . . . . . . . . . 52
8.5. Acct-Session-Time AVP . . . . . . . . . . . . . . . . . 52
8.6. Acct-Authentic AVP . . . . . . . . . . . . . . . . . . . 52
8.7. Accounting-Auth-Method AVP . . . . . . . . . . . . . . . 53
8.8. Acct-Delay-Time . . . . . . . . . . . . . . . . . . . . 53
8.9. Acct-Link-Count . . . . . . . . . . . . . . . . . . . . 54
8.10. Acct-Tunnel-Connection AVP . . . . . . . . . . . . . . . 54
8.11. Acct-Tunnel-Packets-Lost AVP . . . . . . . . . . . . . . 55
9. RADIUS/Diameter Protocol Interactions . . . . . . . . . . . . 55
9.1. RADIUS Request Forwarded as Diameter Request . . . . . . 55
9.1.1. RADIUS Dynamic Authorization Considerations . . 59
9.2. Diameter Request Forwarded as RADIUS Request . . . . . . 60
9.2.1. RADIUS Dynamic Authorization Considerations . . 62
9.3. AVPs Used Only for Compatibility . . . . . . . . . . . . 63
9.3.1. NAS-Identifier AVP. . . . . . . . . . . . . . . 63
9.3.2. NAS-IP-Address AVP. . . . . . . . . . . . . . . 64
9.3.3. NAS-IPv6-Address AVP. . . . . . . . . . . . . . 65
9.3.4. State AVP . . . . . . . . . . . . . . . . . . . 65
9.3.5. Termination-Cause AVP Code Values . . . . . . . 66
9.3.6. Origin-AAA-Protocol . . . . . . . . . . . . . . 68
9.4. Prohibited RADIUS Attributes . . . . . . . . . . . . . . 69
9.5. Translatable Diameter AVPs . . . . . . . . . . . . . . . 69
9.6. RADIUS Vendor-Specific Attributes . . . . . . . . . . . 69
9.6.1. Forwarding a Diameter Vendor Specific AVP as a
RADIUS VSA . . . . . . . . . . . . . . . . . . . 70
9.6.2. Forwarding a RADIUS VSA as a Diameter Vendor
Specific AVP . . . . . . . . . . . . . . . . . . 70
10. AVP Occurrence Tables. . . . . . . . . . . . . . . . . . . . . 71
10.1. AA-Request/Answer AVP Table. . . . . . . . . . . . . . . 71
10.2. Accounting AVP Tables. . . . . . . . . . . . . . . . . . 73
10.2.1. Accounting Framed Access AVP Table. . . . . . . 74
10.2.2. Accounting Non-Framed Access AVP Table. . . . . 76
11. IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 77
11.1. Command Codes. . . . . . . . . . . . . . . . . . . . . . 77
11.2. AVP Codes. . . . . . . . . . . . . . . . . . . . . . . . 78
11.3. Application Identifier . . . . . . . . . . . . . . . . . 78
11.4. CHAP-Algorithm AVP Values. . . . . . . . . . . . . . . . 78
11.5. Accounting-Auth-Method AVP Values. . . . . . . . . . . . 78
11.6. Origin-AAA-Protocol AVP Values . . . . . . . . . . . . . 78
12. Security Considerations. . . . . . . . . . . . . . . . . . . . 78
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 79
13.1. Normative References . . . . . . . . . . . . . . . . . . 79
13.2. Informative References . . . . . . . . . . . . . . . . . 80
14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 83
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 84
Full Copyright Statement . . . . . . . . . . . . . . . . . . . . . 85the big picture is sections 1 through 14, then the authors and the copyright statement at the very end 🌸 next up is the Introduction, so get ready for the good stuff 💅
1. Introduction ✨
okay so bestie, this doc is all about the Diameter protocol application for AAA in the Network Access Server (NAS) environment 🌐. When you combine it with the Diameter Base protocol [BASE], the Transport Profile [DiamTrans], and EAP [DiamEAP], this NAS application spec covers the NAS-related requirements from RFC 2989 [AAACriteria] and RFC 3169 [NASCriteria]. it's giving complete package 💅
early Diameter deployments are gonna include legacy systems, so this application was carefully designed to make protocol conversion between RADIUS and Diameter way easier 🫶. how? it includes the RADIUS attribute space, so you don't have to do a ton of attribute translations. iconic engineering, no cap 🦋
the interactions this document specifies between Diameter applications and RADIUS are meant to apply to all Diameter applications. in that sense, this document extends the Base Diameter protocol [BASE] 🌸
here's the roadmap 🗺️: first, this doc describes how a Diameter NAS application operates. then it defines the Diameter message Command-Codes. after that, the AVPs used in these messages are listed and grouped by common usage: session identification, authentication, authorization, tunneling, and accounting. the authorization AVPs get broken down even further by service type. interaction and backward compatibility issues with RADIUS are covered in the later sections 🎀
1.1. Terminology
the base Diameter [BASE] specification, section 1.4, defines most of the terminology used here. on top of that, this application uses the following terms and acronyms 📚
NAS (Network Access Server) - A device that provides an access service for a user to a network. The service may be a network connection or a value-added service such as terminal emulation [NASModel].
PPP (Point-to-Point Protocol) - A multiprotocol serial datalink. PPP is the primary IP datalink used for dial-in NAS connection service [PPP].
CHAP (Challenge Handshake Authentication Protocol) - An authentication process used in PPP [PPPCHAP].
PAP (Password Authentication Protocol) - A deprecated PPP authentication process, but often used for backward compatibility [PAP].
SLIP (Serial Line Interface Protocol) - A serial datalink that only supports IP. A design prior to PPP.
ARAP (Appletalk Remote Access Protocol) - A serial datalink for accessing Appletalk networks [ARAP].
IPX (Internet Packet Exchange) - The network protocol used by NetWare networks [IPX].
LAT (Local Area Transport) - A Digital Equipment Corp. LAN protocol for terminal services [LAT].
VPN (Virtual Private Network) - In this document, this term is used to describe access services that use tunneling methods.
1.2. Requirements Language
in this document, the key words "MAY", "MUST", "MUST NOT", "OPTIONAL", "RECOMMENDED", "SHOULD", and "SHOULD NOT" are to be interpreted as described in [Keywords] 🔑
1.3. Advertising Application Support
Diameter applications conforming to this specification MUST advertise support by including the value of one (1) in the Auth-Application-Id of Capabilities-Exchange-Request (CER), AA-Request (AAR), and AA-Answer (AAA) messages. All other messages are defined by [BASE] and use the Base application id value. 📣
2. NAS Calls, Ports, and Sessions
okay this is the fun part 🎬. when a new call or service connection shows up at a port of a Network Access Server (NAS), that kicks off a Diameter NAS message exchange. the info about the call, the user's identity, and the user's authentication info all get packed into a Diameter AA-Request (AAR) message and sent off to a server 📦
the server processes everything and replies with a Diameter AA-Answer (AAA) message. that reply has authorization info for the NAS, or a failure code (Result-Code AVP) if things went wrong 😬. a value of DIAMETER_MULTI_ROUND_AUTH means there's another authentication exchange coming, so several AAR and AAA messages can get swapped back and forth until the transaction completes 🔄
depending on the Auth-Request-Type AVP, Diameter lets you send authorization-only requests that have no authentication info from the client. this goes beyond the Call Check capabilities in section 5.6 of [RADIUS], because no access decision is requested here. so service cannot be started based on a response to an authorization-only request without introducing a significant security vulnerability 🚨 not it, not us.
since RADIUS has no equivalent capability, authorization-only requests from a Diameter-implementing NAS may not be easily translated into an equivalent RADIUS message by a Diameter/RADIUS gateway 🥲. for example, when a Diameter authorization-only request can't be translated to a RADIUS Call Check, the gateway would need to add authentication info to the RADIUS Access Request. then, when the Access-Reply comes back, the gateway would need to discard the access decision (Accept/Reject). it's honestly not clear whether these translations can happen without adding significant security vulnerabilities 💀
2.1. Diameter Session Establishment
when the authentication or authorization exchange completes successfully, the NAS application SHOULD start a session context ✨. if DIAMETER_MULTI_ROUND_AUTH is returned as the Result-Code, the exchange keeps going until a success or error comes back 🔁
if accounting is active, the application MUST also send an Accounting message [BASE] 🧾. an Accounting-Record-Type of START_RECORD gets sent for a new session. if a session fails to start, the EVENT_RECORD message gets sent with the reason for the failure described 🙈
also, heads up: getting back an unsupportable Accounting-Realtime-Required value [BASE] would result in a failure to establish the session 🚫
2.2. Diameter Session Reauthentication or Reauthorization
the Diameter Base protocol lets users get periodically reauthenticated and/or reauthorized 🔄💖. in these cases, the Session-Id AVP in the AAR message MUST be the same as the one in the original authentication/authorization message 🆔
a Diameter server tells the NAS the maximum time allowed before reauthentication or reauthorization through the Authorization-Lifetime AVP [BASE] ⏰. a NAS MAY reauthenticate and/or reauthorize before the end, but A NAS MUST reauthenticate and/or reauthorize at the end of the period provided by the Authorization-Lifetime AVP. and if a reauthentication exchange fails, the service gets terminated 💔
it's also possible for Diameter servers to send an unsolicited reauthentication and/or reauthorization request (e.g., Re-Auth-Request (RAR) message [BASE]) to the NAS 📬. when the NAS gets one of these, it MUST respond with a Re-Auth-Answer (RAA) message [BASE] 🫡
if the RAR properly identifies an active session, the NAS starts a new local reauthentication or authorization sequence, as indicated by the Re-Auth-Request-Type value 🎯. that makes the NAS send a new AAR message using the existing Session-Id. the server responds with an AAA message to specify the new service parameters 🪄
if accounting is active, every change of authentication or authorization SHOULD generate an accounting message 📊. if the NAS service is a continuation of the prior user context, an Accounting-Record-Type of INTERIM_RECORD is appropriate, showing the new session attributes and cumulative status 📈. if the NAS detects a new user or a significant change in authorization, the service may send two messages, of the types STOP_RECORD and START_RECORD 🔀. accounting may change the subsession identifiers (Acct-Session-ID, or Acct-Sub-Session-Id) to indicate those sub-sessions 🪆. a service may also use a different Session-Id value for accounting (see [BASE] section 9.6) 🎀
however, the Diameter Session-ID AVP value used for the initial authorization exchange MUST be used to generate an STR message when the session context is terminated 🔚
2.3. Diameter Session Termination
when a NAS gets an indication that a user's session is being disconnected by the client (e.g., LCP Terminate is received) or by an administrative command, the NAS MUST issue a Session-Termination-Request (STR) [BASE] to its Diameter Server 🛑. this makes sure any resources kept on the servers get freed up properly 🧹
also, a NAS that receives an Abort-Session-Request (ASR) [BASE] MUST issue an ASA if the session identified is active, and it MUST disconnect the PPP (or tunneling) session 📴
if accounting is active, an Accounting STOP_RECORD message [BASE] MUST be sent when the session context is terminated 🏁
more info on Diameter Session Termination lives in [BASE] sections 8.4 and 8.5 📖
3. NAS Messages
this section defines the Diameter message Command-Code [BASE] values that MUST be supported by all Diameter implementations conforming to this specification 💅. here are the Command Codes:
Command-Name Abbrev. Code Reference
-------------------------------------------------------
AA-Request AAR 265 3.1
AA-Answer AAA 265 3.2
Re-Auth-Request RAR 258 3.3
Re-Auth-Answer RAA 258 3.4
Session-Termination-Request STR 275 3.5
Session-Termination-Answer STA 275 3.6
Abort-Session-Request ASR 274 3.7
Abort-Session-Answer ASA 274 3.8
Accounting-Request ACR 271 3.9
Accounting-Answer ACA 271 3.103.1. AA-Request (AAR) Command ✨
okay so the AA-Request (AAR) is the message you send when you want authentication and/or authorization for a NAS user 🎀. You can spot it by Command-Code 265 plus the 'R' bit set in the Command Flags field 💅. The type of request gets picked with the Auth-Request-Type AVP [BASE]. The recommended value for most RADIUS interoperability situations is AUTHORIZE_AUTHENTICATE 🦋.
If you're asking for authentication, the User-Name attribute SHOULD be there, plus any extra authentication AVPs that carry the password info 🔐. An authorization request SHOULD only include the info the authorization is actually done with, like the User-Name, Called-Station-Id, or Calling-Station-Id AVPs 🙈. Every request SHOULD have AVPs that uniquely identify where the call came from, like Origin-Host and NAS-Port 🌸. Certain networks MAY use different AVPs for authorization purposes 💜. An authorization request will include some AVPs defined in section 6 ✨.
It's totally possible for a single session to get authorized first and then have an authentication request follow 🧚.
This AA-Request message MAY be the result of a multi-round authentication exchange, which happens when the AA-Answer message comes back with the Result-Code AVP set to DIAMETER_MULTI_ROUND_AUTH 🔥. A subsequent AAR message SHOULD be sent, with the User-Password AVP holding the user's response to the prompt, and it MUST include any State AVPs that were present in the AAA message 💀.
Message Format
<AA-Request> ::= < Diameter Header: 265, REQ, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ Auth-Request-Type }
[ Destination-Host ]
[ NAS-Identifier ]
[ NAS-IP-Address ]
[ NAS-IPv6-Address ]
[ NAS-Port ]
[ NAS-Port-Id ]
[ NAS-Port-Type ]
[ Origin-AAA-Protocol ]
[ Origin-State-Id ]
[ Port-Limit ]
[ User-Name ]
[ User-Password ]
[ Service-Type ]
[ State ]
[ Authorization-Lifetime ]
[ Auth-Grace-Period ]
[ Auth-Session-State ]
[ Callback-Number ]
[ Called-Station-Id ]
[ Calling-Station-Id ]
[ Originating-Line-Info ]
[ Connect-Info ]
[ CHAP-Auth ]
[ CHAP-Challenge ]
* [ Framed-Compression ]
[ Framed-Interface-Id ]
[ Framed-IP-Address ]
* [ Framed-IPv6-Prefix ]
[ Framed-IP-Netmask ]
[ Framed-MTU ]
[ Framed-Protocol ]
[ ARAP-Password ]
[ ARAP-Security ]
* [ ARAP-Security-Data ]
* [ Login-IP-Host ]
* [ Login-IPv6-Host ]
[ Login-LAT-Group ]
[ Login-LAT-Node ]
[ Login-LAT-Port ]
[ Login-LAT-Service ]
* [ Tunneling ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]3.2. AA-Answer (AAA) Command ✨
the AA-Answer (AAA) message is the reply, and you know it because Command-Code is 265 and the 'R' bit is cleared in the Command Flags field 🦋. It gets sent back in response to the AA-Request (AAR) message. If authorization was asked for, a successful response includes the authorization AVPs that fit the service being provided, as defined in section 6 💖.
For authentication exchanges that need more than a single round trip, the server MUST set the Result-Code AVP to DIAMETER_MULTI_ROUND_AUTH 🔥. An AAA message with this result code MAY include one Reply-Message or more, and MAY include zero or one State AVPs 🌈.
If the Reply-Message AVP was there, the network access server SHOULD send the text to the user's client so it can show up for the user, telling the client to prompt them for a response 📣. For example, this can be done in PPP via PAP 🎀. If the access client can't prompt the user for a new response, it MUST treat the AA-Answer (AAA) with the Reply-Message AVP as an error and deny access 🚫. no exceptions, bestie 💀.
Message Format
<AA-Answer> ::= < Diameter Header: 265, PXY >
< Session-Id >
{ Auth-Application-Id }
{ Auth-Request-Type }
{ Result-Code }
{ Origin-Host }
{ Origin-Realm }
[ User-Name ]
[ Service-Type ]
* [ Class ]
* [ Configuration-Token ]
[ Acct-Interim-Interval ]
[ Error-Message ]
[ Error-Reporting-Host ]
* [ Failed-AVP ]
[ Idle-Timeout ]
[ Authorization-Lifetime ]
[ Auth-Grace-Period ]
[ Auth-Session-State ]
[ Re-Auth-Request-Type ]
[ Multi-Round-Time-Out ]
[ Session-Timeout ]
[ State ]
* [ Reply-Message ]
[ Origin-AAA-Protocol ]
[ Origin-State-Id ]
* [ Filter-Id ]
[ Password-Retry ]
[ Port-Limit ]
[ Prompt ]
[ ARAP-Challenge-Response ]
[ ARAP-Features ]
[ ARAP-Security ]
* [ ARAP-Security-Data ]
[ ARAP-Zone-Access ]
[ Callback-Id ]
[ Callback-Number ]
[ Framed-Appletalk-Link ]
* [ Framed-Appletalk-Network ]
[ Framed-Appletalk-Zone ]
* [ Framed-Compression ]
[ Framed-Interface-Id ]
[ Framed-IP-Address ]
* [ Framed-IPv6-Prefix ]
[ Framed-IPv6-Pool ]
* [ Framed-IPv6-Route ]
[ Framed-IP-Netmask ]
* [ Framed-Route ]
[ Framed-Pool ]
[ Framed-IPX-Network ]
[ Framed-MTU ]
[ Framed-Protocol ]
[ Framed-Routing ]
* [ Login-IP-Host ]
* [ Login-IPv6-Host ]
[ Login-LAT-Group ]
[ Login-LAT-Node ]
[ Login-LAT-Port ]
[ Login-LAT-Service ]
[ Login-Service ]
[ Login-TCP-Port ]
* [ NAS-Filter-Rule ]
* [ QoS-Filter-Rule ]
* [ Tunneling ]
* [ Redirect-Host ]
[ Redirect-Host-Usage ]
[ Redirect-Max-Cache-Time ]
* [ Proxy-Info ]
* [ AVP ]3.3. Re-Auth-Request (RAR) Command ✨
a Diameter server may kick off a re-authentication and/or re-authorization for a particular session by sending a Re-Auth-Request (RAR) message [BASE] 🔄.
for example, with pre-paid services, the Diameter server that first authorized a session might need some confirmation that the user is still using the service 💸.
if a NAS gets an RAR message whose Session-Id matches a currently active session and whose Re-Auth-Type includes authentication, it MUST initiate a re-authentication toward the user, as long as the service supports this particular feature 🔐.
Message Format
<RA-Request> ::= < Diameter Header: 258, REQ, PXY >
< Session-Id >
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ Destination-Host }
{ Auth-Application-Id }
{ Re-Auth-Request-Type }
[ User-Name ]
[ Origin-AAA-Protocol ]
[ Origin-State-Id ]
[ NAS-Identifier ]
[ NAS-IP-Address ]
[ NAS-IPv6-Address ]
[ NAS-Port ]
[ NAS-Port-Id ]
[ NAS-Port-Type ]
[ Service-Type ]
[ Framed-IP-Address ]
[ Framed-IPv6-Prefix ]
[ Framed-Interface-Id ]
[ Called-Station-Id ]
[ Calling-Station-Id ]
[ Originating-Line-Info ]
[ Acct-Session-Id ]
[ Acct-Multi-Session-Id ]
[ State ]
* [ Class ]
[ Reply-Message ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]3.4. Re-Auth-Answer (RAA) Command ✨
the Re-Auth-Answer (RAA) message [BASE] is the reply to the RAR 💌. The Result-Code AVP MUST be present, and it tells you how the request went 📋.
a successful RAA transaction MUST be followed by an AAR message 🫶.
Message Format
<RA-Answer> ::= < Diameter Header: 258, PXY >
< Session-Id >
{ Result-Code }
{ Origin-Host }
{ Origin-Realm }
[ User-Name ]
[ Origin-AAA-Protocol ]
[ Origin-State-Id ]
[ Error-Message ]
[ Error-Reporting-Host ]
* [ Failed-AVP ]
* [ Redirected-Host ]
[ Redirected-Host-Usage ]
[ Redirected-Host-Cache-Time ]
[ Service-Type ]
* [ Configuration-Token ]
[ Idle-Timeout ]
[ Authorization-Lifetime ]
[ Auth-Grace-Period ]
[ Re-Auth-Request-Type ]
[ State ]
* [ Class ]
* [ Reply-Message ]
[ Prompt ]
* [ Proxy-Info ]
* [ AVP ]3.5. Session-Termination-Request (STR) Command
okay so the NAS uses the Session-Termination-Request (STR) message [BASE] to let the Diameter Server know that a session it had authenticated and/or authorized is wrapping up 🌸 bye bye session!
Message Format
<ST-Request> ::= < Diameter Header: 275, REQ, PXY >
< Session-Id >
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ Auth-Application-Id }
{ Termination-Cause }
[ User-Name ]
[ Destination-Host ]
* [ Class ]
[ Origin-AAA-Protocol ]
[ Origin-State-Id ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]3.6. Session-Termination-Answer (STA) Command
The Session-Termination-Answer (STA) message [BASE] is the Diameter Server's "got it, the session is over" reply 💅 The Result-Code AVP MUST be present, and it MAY contain an indication that an error occurred while the STR was being serviced.
Once the STA is sent or received, the Diameter Server MUST release all resources for the session indicated by the Session-Id AVP 🧹 Any intermediate server in the Proxy-Chain MAY also release any resources, if necessary.
Message Format
<ST-Answer> ::= < Diameter Header: 275, PXY >
< Session-Id >
{ Result-Code }
{ Origin-Host }
{ Origin-Realm }
[ User-Name ]
* [ Class ]
[ Error-Message ]
[ Error-Reporting-Host ]
* [ Failed-AVP ]
[ Origin-AAA-Protocol ]
[ Origin-State-Id ]
* [ Redirect-Host ]
[ Redirect-Host-Usase ]
[ Redirect-Max-Cache-Time ]
* [ Proxy-Info ]
* [ AVP ]3.7. Abort-Session-Request (ASR) Command
The Abort-Session-Request (ASR) message [BASE] is the "hey, stop that session right now" message 🚨 Any server is allowed to send it to the NAS that's providing session service, asking it to stop the session identified by the Session-Id.
Message Format
<AS-Request> ::= < Diameter Header: 274, REQ, PXY >
< Session-Id >
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ Destination-Host }
{ Auth-Application-Id }
[ User-Name ]
[ Origin-AAA-Protocol ]
[ Origin-State-Id ]
[ NAS-Identifier ]
[ NAS-IP-Address ]
[ NAS-IPv6-Address ]
[ NAS-Port ]
[ NAS-Port-Id ]
[ NAS-Port-Type ]
[ Service-Type ]
[ Framed-IP-Address ]
[ Framed-IPv6-Prefix ]
[ Framed-Interface-Id ]
[ Called-Station-Id ]
[ Calling-Station-Id ]
[ Originating-Line-Info ]
[ Acct-Session-Id ]
[ Acct-Multi-Session-Id ]
[ State ]
* [ Class ]
* [ Reply-Message ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]3.8. Abort-Session-Answer (ASA) Command
The ASA message [BASE] is the reply to the ASR 🎀 The Result-Code AVP MUST be present, and it tells everyone how the request turned out.
If the session identified by Session-Id in the ASR was successfully terminated, Result-Code is set to DIAMETER_SUCCESS ✨ If the session is not currently active, Result-Code is set to DIAMETER_UNKNOWN_SESSION_ID 🙈 If the access device does not stop the session for any other reason, Result-Code is set to DIAMETER_UNABLE_TO_COMPLY 💀
Message Format
<AS-Answer> ::= < Diameter Header: 274, PXY >
< Session-Id >
{ Result-Code }
{ Origin-Host }
{ Origin-Realm }
[ User-Name ]
[ Origin-AAA-Protocol ]
[ Origin-State-Id ]
[ State]
[ Error-Message ]
[ Error-Reporting-Host ]
* [ Failed-AVP ]
* [ Redirected-Host ]
[ Redirected-Host-Usage ]
[ Redirected-Max-Cache-Time ]
* [ Proxy-Info ]
* [ AVP ]3.9. Accounting-Request (ACR) Command
The ACR message [BASE] is how the NAS reports its session info to a target server downstream 📊
Either Acct-Application-Id or Vendor-Specific-Application-Id AVPs MUST be present 🫶 If the Vendor-Specific-Application-Id grouped AVP is present, it must have an Acct-Application-Id inside.
The AVPs listed in the Base MUST be assumed to be present, as appropriate. NAS service-specific accounting AVPs SHOULD be present as described in section 8 and the rest of this specification 🌈
Message Format
<AC-Request> ::= < Diameter Header: 271, REQ, PXY >
< Session-Id >
{ Origin-Host }
{ Origin-Realm }
{ Destination-Realm }
{ Accounting-Record-Type }
{ Accounting-Record-Number }
[ Acct-Application-Id ]
[ Vendor-Specific-Application-Id ]
[ User-Name ]
[ Accounting-Sub-Session-Id ]
[ Acct-Session-Id ]
[ Acct-Multi-Session-Id ]
[ Origin-AAA-Protocol ]
[ Origin-State-Id ]
[ Destination-Host ]
[ Event-Timestamp ]
[ Acct-Delay-Time ]
[ NAS-Identifier ]
[ NAS-IP-Address ]
[ NAS-IPv6-Address ]
[ NAS-Port ]
[ NAS-Port-Id ]
[ NAS-Port-Type ]
* [ Class ]
[ Service-Type ]
[ Termination-Cause ]
[ Accounting-Input-Octets ]
[ Accounting-Input-Packets ]
[ Accounting-Output-Octets ]
[ Accounting-Output-Packets ]
[ Acct-Authentic ]
[ Accounting-Auth-Method ]
[ Acct-Link-Count ]
[ Acct-Session-Time ]
[ Acct-Tunnel-Connection ]
[ Acct-Tunnel-Packets-Lost ]
[ Callback-Id ]
[ Callback-Number ]
[ Called-Station-Id ]
[ Calling-Station-Id ]
* [ Connection-Info ]
[ Originating-Line-Info ]
[ Authorization-Lifetime ]
[ Session-Timeout ]
[ Idle-Timeout ]
[ Port-Limit ]
[ Accounting-Realtime-Required ]
[ Acct-Interim-Interval ]
* [ Filter-Id ]
* [ NAS-Filter-Rule ]
* [ Qos-Filter-Rule ]
[ Framed-AppleTalk-Link ]
[ Framed-AppleTalk-Network ]
[ Framed-AppleTalk-Zone ]
[ Framed-Compression ]
[ Framed-Interface-Id ]
[ Framed-IP-Address ]
[ Framed-IP-Netmask ]
* [ Framed-IPv6-Prefix ]
[ Framed-IPv6-Pool ]
* [ Framed-IPv6-Route ]
[ Framed-IPX-Network ]
[ Framed-MTU ]
[ Framed-Pool ]
[ Framed-Protocol ]
* [ Framed-Route ]
[ Framed-Routing ]
* [ Login-IP-Host ]
* [ Login-IPv6-Host ]
[ Login-LAT-Group ]
[ Login-LAT-Node ]
[ Login-LAT-Port ]
[ Login-LAT-Service ]
[ Login-Service ]
[ Login-TCP-Port ]
* [ Tunneling ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]3.10. Accounting-Answer (ACA) Command
The ACA message [BASE] is the acknowledgement for an Accounting-Request command 💖 The Accounting-Answer command carries the same Session-Id as the Request. If the Accounting-Request was protected by end-to-end security, then the corresponding ACA message MUST be protected as well 🔐
Only the target Diameter Server or home Diameter Server SHOULD respond with the Accounting-Answer command 👑
Either Acct-Application-Id or Vendor-Specific-Application-Id AVPs MUST be present, just like they were in the request.
The AVPs listed in the Base MUST be assumed to be present, as appropriate. NAS service-specific accounting AVPs SHOULD be present as described in section 8 and the rest of this specification ✨
Message Format
<AC-Answer> ::= < Diameter Header: 271, PXY >
< Session-Id >
{ Result-Code }
{ Origin-Host }
{ Origin-Realm }
{ Accounting-Record-Type }
{ Accounting-Record-Number }
[ Acct-Application-Id ]
[ Vendor-Specific-Application-Id ]
[ User-Name ]
[ Accounting-Sub-Session-Id ]
[ Acct-Session-Id ]
[ Acct-Multi-Session-Id ]
[ Event-Timestamp ]
[ Error-Message ]
[ Error-Reporting-Host ]
* [ Failed-AVP ]
[ Origin-AAA-Protocol ]
[ Origin-State-Id ]
[ NAS-Identifier ]
[ NAS-IP-Address ]
[ NAS-IPv6-Address ]
[ NAS-Port ]
[ NAS-Port-Id ]
[ NAS-Port-Type ]
[ Service-Type ]
[ Termination-Cause ]
[ Accounting-Realtime-Required ]
[ Acct-Interim-Interval ]
* [ Class ]
* [ Proxy-Info ]
* [ Route-Record ]
* [ AVP ]4. NAS Session AVPs ✨
Diameter reserves the AVP Codes 0 - 255 for RADIUS functions that are implemented in Diameter 🧚
AVPs new to Diameter have code values of 256 and greater. A Diameter message that includes one of these AVPs may represent functions not present in the RADIUS environment, and it may cause interoperability issues if the request traverses an AAA system that only supports the RADIUS protocol 🙈
Some RADIUS attributes are not allowed or supported directly in Diameter. See section 9 for more information 🦋
4.1. Call and Session Information 💖
okay so this section is where we get the AVPs that are specific to NAS Diameter applications 🎀. they help identify the call and session context and the status info. on a request, this info lets the server qualify the session, which is giving main character energy ✨
these AVPs get used on top of the Base AVPs, which are:
Session-IdAuth-Application-IdOrigin-HostOrigin-RealmAuth-Request-TypeTermination-Cause
ok and here's the session-level table 🦋. it lists the AVP Code values, the types, the possible flag values, and whether each AVP MAY be encrypted 🔐
+---------------------+
| AVP Flag rules |
|----+-----+----+-----|----+
AVP Section | | |SHLD| MUST| |
Attribute Name Code Defined Value Type |MUST| MAY | NOT| NOT|Encr|
-----------------------------------------|----+-----+----+-----|----|
NAS-Port 5 4.2 Unsigned32 | M | P | | V | Y |
NAS-Port-Id 87 4.3 UTF8String | M | P | | V | Y |
NAS-Port-Type 61 4.4 Enumerated | M | P | | V | Y |
Called-Station-Id 30 4.5 UTF8String | M | P | | V | Y |
Calling-Station- 31 4.6 UTF8String | M | P | | V | Y |
Id | | | | | |
Connect-Info 77 4.7 UTF8String | M | P | | V | Y |
Originating-Line- 94 4.8 OctetString| | M,P | | V | Y |
Info | | | | | |
Reply-Message 18 4.9 UTF8String | M | P | | V | Y |
-----------------------------------------|----+-----+----+-----|----|4.2. NAS-Port AVP 🌸
the NAS-Port AVP (AVP Code 5) is of type Unsigned32 🔢. it holds the physical or virtual port number of the NAS that's authenticating the user. quick heads up: "port" here means a service connection on the NAS, NOT an IP protocol identifier, so don't mix those up 🙅♀️
either NAS-Port or NAS-Port-Id (AVP Code 87) SHOULD be present in AA-Request (AAR) commands if the NAS differentiates among its ports ✨
4.3. NAS-Port-Id AVP 🧚
the NAS-Port-Id AVP (AVP Code 87) is of type UTF8String and is made of ASCII text that identifies the port of the NAS authenticating the user 💅. same deal as before: "port" means a service connection on the NAS, not an IP protocol identifier.
either NAS-Port or NAS-Port-Id SHOULD be present in AA-Request (AAR) commands if the NAS differentiates among its ports. NAS-Port-Id is intended for use by NASes that cannot conveniently number their ports 🫶
4.4. NAS-Port-Type AVP 🍓
the NAS-Port-Type AVP (AVP Code 61) is of type Enumerated and tells you the type of port the NAS is authenticating the user on 📡. this AVP SHOULD be present if the NAS uses the same NAS-Port number ranges for different service types at the same time 😭
the supported values are defined in [RADIUSTypes]. the list below is informational and can be changed by the IANA, so don't get too attached 🙈
0 Async
1 Sync
2 ISDN Sync
3 ISDN Async V.120
4 ISDN Async V.110
5 Virtual
6 PIAFS
7 HDLC Clear Channel
8 X.25
9 X.75
10 G.3 Fax
11 SDSL - Symmetric DSL
12 ADSL-CAP - Asymmetric DSL, Carrierless Amplitude Phase
Modulation
13 ADSL-DMT - Asymmetric DSL, Discrete Multi-Tone
14 IDSL - ISDN Digital Subscriber Line
15 Ethernet
16 xDSL - Digital Subscriber Line of unknown type
17 Cable
18 Wireless - Other
19 Wireless - IEEE 802.11
20 Token-Ring [RAD802.1X]
21 FDDI [RAD802.1X]
22 Wireless - CDMA2000
23 Wireless - UMTS
24 Wireless - 1X-EV
25 IAPP [IEEE 802.11f]4.5. Called-Station-Id AVP 📞
the Called-Station-Id AVP (AVP Code 30) is of type UTF8String 💌. it lets the NAS send an ASCII string describing the layer 2 address the user contacted in the request. for dialup access, this can be a phone number picked up with Dialed Number Identification (DNIS) or a similar tech 📲. note that this may be different from the phone number the call came in on 🤔. for use with IEEE 802 access, the Called-Station-Id MAY contain a MAC address formatted as described in [RAD802.1X]. it SHOULD only be present in authentication and/or authorization requests 💖
if the Auth-Request-Type AVP is set to authorization-only and the User-Name AVP is absent, the Diameter Server MAY perform authorization based on this field 👀. this can be used by a NAS to ask whether a call should be answered based on the DNIS, which is so smart 🧠
the codification of this field's allowed usage range is outside the scope of this specification 🙃
4.6. Calling-Station-Id AVP 📱
the Calling-Station-Id AVP (AVP Code 31) is of type UTF8String ✨. it lets the NAS send an ASCII string describing the layer 2 address the user connected from. for dialup access, that's the phone number the call came from, using Automatic Number Identification (ANI) or a similar tech 📞. for use with IEEE 802 access, the Calling-Station-Id AVP MAY contain a MAC address, formated as described in [RAD802.1X]. it SHOULD only be present in authentication and/or authorization requests 🫶
if the Auth-Request-Type AVP is set to authorization-only and the User-Name AVP is absent, the Diameter Server MAY perform authorization based on this field 🔥. this can be used by a NAS to ask whether a call should be answered based on the layer 2 address (ANI, MAC Address, etc.)
the codification of this field's allowed usage range is outside the scope of this specification 💅
4.7. Connect-Info AVP 🔌
the Connect-Info AVP (AVP Code 77) is of type UTF8String and gets sent in the AA-Request message or the ACR STOP message 🚀. when it's sent in the Access-Request, it tells you the nature of the user's connection. the connection speed SHOULD be included at the beginning of the first Connect-Info AVP in the message 💨. if the transmit and receive connection speeds differ, both may be included in the first AVP. the transmit speed goes first (that's the speed the NAS modem transmits at), then a slash (/), then the receive speed, and then any other optional info 🎀
for example: "28800 V42BIS/LAPM" or "52000/31200 V90" 🌈
more than one Connect-Info attribute may be present in an Accounting-Request packet 🗂️. that's to accommodate the ITU's expected efforts to have modems report more connection info in a standard format that might go over 252 octets, which is a lot of info, honestly 😭
if it's sent in the ACR STOP, this attribute may summarize statistics about session quality ⭐. for example, in IEEE 802.11, the Connect-Info attribute may contain info on the number of link layer retransmissions. the exact format of this attribute is implementation specific, so it's up to whoever builds it 🧚
4.8. Originating-Line-Info AVP 📟
the Originating-Line-Info AVP (AVP Code 94) is of type OctetString 🦋. the NAS sends it to convey info about where a call came from in an SS7 system.
the originating line information (OLI) element tells you the nature and/or characteristics of the line the call started on, like a pay phone, a hotel, or a cellular line 📱. telephone companies are starting to offer OLI to their customers as an option over Primary Rate Interface (PRI) 🏢. ISPs can use OLI together with Called-Station-Id and Calling-Station-Id to tell customer calls apart and define different services 👑
the Value field contains two octets (00 - 99). ANSI T1.113 and BELLCORE 394 can be used for more info on these values and how they're used 📚. for more info on current assignment values, check [ANITypes] 💜
Value Description
------------------------------------------------------------
00 Plain Old Telephone Service (POTS)
01 Multiparty Line (more than 2)
02 ANI Failure
03 ANI Observed
04 ONI Observed
05 ANI Failure Observed
06 Station Level Rating
07 Special Operator Handling Required
08 InterLATA Restricted
10 Test Call
20 Automatic Identified Outward Dialing (AIOD)
23 Coin or Non-Coin
24 Toll Free Service (Non-Pay Origination)
25 Toll Free Service (Pay Origination)
27 Toll Free Service (Coin Control Origination)
29 Prison/Inmate Service
30-32 Intercept
30 Intercept (Blank)
31 Intercept (Trouble)
32 Intercept (Regular)
34 Telco Operator Handled Call
40-49 Unrestricted Use
52 Outward Wide Area Telecommunications Service (OUTWATS)
60 Telecommunications Relay Service (TRS)(Unrestricted)
61 Cellular/Wireless PCS (Type 1)
62 Cellular/Wireless PCS (Type 2)
63 Cellular/Wireless PCS (Roaming)
66 TRS (Hotel)
67 TRS (Restricted)
70 Pay Station, No Coin Control
93 Access for Private Virtual Network Service4.9. Reply-Message AVP 💬
the Reply-Message AVP (AVP Code 18) is of type UTF8String and holds text that MAY be displayed to the user 💖. when it's used in an AA-Answer message with a successful Result-Code AVP, it means success 🎉. when it shows up in an AAA message with a Result-Code other than DIAMETER_SUCCESS, the AVP carries a failure message 😬
the Reply-Message AVP MAY indicate dialog text to prompt the user before another AA-Request attempt ✨. when it's used in an AA-Answer with a Result-Code of DIAMETER_MULTI_ROUND_AUTH, or in a Re-Auth-Request message, it MAY contain dialog text to prompt the user for a response 🌸
multiple Reply-Messages MAY be included, and if any are displayed, they MUST be displayed in the same order as they appear in the Diameter message 🫶. order matters, bestie, no cap 💅
5. NAS Authentication AVPs ✨
Okay bestie, this section is where the auth magic happens 🔐 It defines the AVPs that carry the authentication info in Diameter. It gives RADIUS-like AAA vibes, but over a more reliable and secure transport, as the base protocol [BASE] explains 💅
Here's the table of AVPs, with their AVP Code values, types, possible flag values, and whether the AVP MAY be encrypted:
+---------------------+
| AVP Flag rules |
|----+-----+----+-----|----+
AVP Section | | |SHLD| MUST| |
Attribute Name Code Defined Value Type |MUST| MAY | NOT| NOT|Encr|
-----------------------------------------|----+-----+----+-----|----|
User-Password 2 5.1 OctetString| M | P | | V | Y |
Password-Retry 75 5.2 Unsigned32 | M | P | | V | Y |
Prompt 76 5.3 Enumerated | M | P | | V | Y |
CHAP-Auth 402 5.4 Grouped | M | P | | V | Y |
CHAP-Algorithm 403 5.5 Enumerated | M | P | | V | Y |
CHAP-Ident 404 5.6 OctetString| M | P | | V | Y |
CHAP-Response 405 5.7 OctetString| M | P | | V | Y |
CHAP-Challenge 60 5.8 OctetString| M | P | | V | Y |
ARAP-Password 70 5.9 OctetString| M | P | | V | Y |
ARAP-Challenge- 84 5.10 OctetString| M | P | | V | Y |
Response | | | | | |
ARAP-Security 73 5.11 Unsigned32 | M | P | | V | Y |
ARAP-Security- 74 5.12 OctetString| M | P | | V | Y |
Data | | | | | |
-----------------------------------------|----+-----+----+-----|----|5.1. User-Password AVP 🙈
The User-Password AVP (AVP Code 2) is an OctetString. It holds the password of the user being authenticated, or the user's input during a multi-round authentication exchange.
This one is sensitive, bestie 😭 It contains a user password or a one-time password. As [BASE] requires, Diameter messages get encrypted with IPsec or TLS. Unless this AVP is used for one-time passwords, the User-Password AVP SHOULD NOT be used in untrusted proxy environments without encrypting it by using end-to-end security techniques, such as the proposed CMS Security [DiamCMS].
The clear-text password (prior to encryption) MUST NOT be longer than 128 bytes in length. 🔒
5.2. Password-Retry AVP
The Password-Retry AVP (AVP Code 75) is an Unsigned32 and MAY be included in the AA-Answer if the Result-Code indicates an authentication failure. Its value tells you how many authentication attempts a user is allowed before getting disconnected. It's mainly meant for when the Framed-Protocol AVP (see section 6.10.1) is set to ARAP.
5.3. Prompt AVP 🎀
The Prompt AVP (AVP Code 76) is an Enumerated and MAY be present in the AA-Answer message. When it's there, the NAS uses it to figure out whether the user's response should be echoed as they type it.
The supported values are listed in [RADIUSTypes]. The following list is informational:
0 No Echo
1 Echo5.4. CHAP-Auth AVP 🧁
The CHAP-Auth AVP (AVP Code 402) is a Grouped AVP. It has everything needed to authenticate a user with the PPP Challenge-Handshake Authentication Protocol (CHAP) [PPPCHAP]. If the CHAP-Auth AVP shows up in a message, the CHAP-Challenge AVP MUST be present as well. The optional AVPs with the CHAP response depend on the value of the CHAP-Algorithm AVP. Here's the ABNF grammar for this grouped AVP:
CHAP-Auth ::= < AVP Header: 402 >
{ CHAP-Algorithm }
{ CHAP-Ident }
[ CHAP-Response ]
* [ AVP ]5.5. CHAP-Algorithm AVP 🧮
The CHAP-Algorithm AVP (AVP Code 403) is an Enumerated. It carries the algorithm identifier used when computing the CHAP response [PPPCHAP]. These values are currently supported:
CHAP with MD5 5
The CHAP response is computed by using the procedure described
in [PPPCHAP]. This algorithm requires that the CHAP-Response
AVP MUST be present in the CHAP-Auth AVP.5.6. CHAP-Ident AVP 🪪
The CHAP-Ident AVP (AVP Code 404) is an OctetString. It contains the 1 octet CHAP Identifier used in computing the CHAP response [PPPCHAP].
5.7. CHAP-Response AVP 💌
The CHAP-Response AVP (AVP Code 405) is an OctetString. It contains the 16 octet authentication data the user gave in response to the CHAP challenge [PPPCHAP].
5.8. CHAP-Challenge AVP ⚡
The CHAP-Challenge AVP (AVP Code 60) is an OctetString. It contains the CHAP Challenge that the NAS sent to the CHAP peer [PPPCHAP].
5.9. ARAP-Password AVP 🦋
The ARAP-Password AVP (AVP Code 70) is an OctetString. It's only present when the Framed-Protocol AVP (see section 6.10.1) is included in the message and set to ARAP. This AVP MUST NOT be present if either the User-Password or the CHAP-Auth AVP is present. For more on what goes in this AVP, check [RADIUSExt].
5.10. ARAP-Challenge-Response AVP 🌸
The ARAP-Challenge-Response AVP (AVP Code 84) is an OctetString. It's only present when the Framed-Protocol AVP (see section 6.10.1) is included in the message and set to ARAP. It holds an 8 octet response to the dial-in client's challenge.
Here's the vibe: the RADIUS server works this out by taking the dial-in client's challenge from the high-order 8 octets of the ARAP-Password AVP, then doing DES encryption on that value with the authenticating user's password as the key. If the user's password is fewer than 8 octets long, it gets padded at the end with NULL octets up to a length of 8 before it's used as a key. Iconic math, honestly 🤓
5.11. ARAP-Security AVP 🛡️
The ARAP-Security AVP (AVP Code 73) is an Unsigned32 and MAY be present in the AA-Answer message if the Framed-Protocol AVP (see section 6.10.1) is set to the value of ARAP and the Result-Code AVP is set to DIAMETER_MULTI_ROUND_AUTH. For more on its format, see [RADIUSExt].
5.12. ARAP-Security-Data AVP 🔁
The ARAP-Security AVP (AVP Code 74) is an OctetString and MAY be present in the AA-Request or AA-Answer message if the Framed-Protocol AVP is set to the value of ARAP and the Result-Code AVP is set to DIAMETER_MULTI_ROUND_AUTH. It contains the security module challenge or response associated with the ARAP Security Module specified in ARAP-Security.
6. NAS Authorization AVPs 👑
This section covers the authorization AVPs supported in the NAS Application. The Service-Type AVP SHOULD be present in all messages. Based on its value, additional AVPs defined in this section and in section 7 MAY be present. ✨
Due to space constraints, the short-form IPFltrRule is used to represent IPFilterRule, and QoSFltrRule is used for QoSFilterRule. 💅
+---------------------+
| AVP Flag rules |
|----+-----+----+-----|----+
AVP Section | | |SHLD| MUST| |
Attribute Name Code Defined Value Type |MUST| MAY | NOT| NOT|Encr|
-----------------------------------------|----+-----+----+-----|----|
Service-Type 6 6.1 Enumerated | M | P | | V | Y |
Callback-Number 19 6.2 UTF8String | M | P | | V | Y |
Callback-Id 20 6.3 UTF8String | M | P | | V | Y |
Idle-Timeout 28 6.4 Unsigned32 | M | P | | V | Y |
Port-Limit 62 6.5 Unsigned32 | M | P | | V | Y |
NAS-Filter-Rule 400 6.6 IPFltrRule | M | P | | V | Y |
Filter-Id 11 6.7 UTF8String | M | P | | V | Y |
Configuration- 78 6.8 OctetString| M | | | P,V | |
Token | | | | | |
QoS-Filter-Rule 407 6.9 QoSFltrRule| | | | | |
Framed-Protocol 7 6.10.1 Enumerated | M | P | | V | Y |
Framed-Routing 10 6.10.2 Enumerated | M | P | | V | Y |
Framed-MTU 12 6.10.3 Unsigned32 | M | P | | V | Y |
Framed- 13 6.10.4 Enumerated | M | P | | V | Y |
Compression | | | | | |
Framed-IP-Address 8 6.11.1 OctetString| M | P | | V | Y |
Framed-IP-Netmask 9 6.11.2 OctetString| M | P | | V | Y |
Framed-Route 22 6.11.3 UTF8String | M | P | | V | Y |
Framed-Pool 88 6.11.4 OctetString| M | P | | V | Y |
Framed- 96 6.11.5 Unsigned64 | M | P | | V | Y |
Interface-Id | | | | | |
Framed-IPv6- 97 6.11.6 OctetString| M | P | | V | Y |
Prefix | | | | | |
Framed-IPv6- 99 6.11.7 UTF8String | M | P | | V | Y |
Route | | | | | |
Framed-IPv6-Pool 100 6.11.8 OctetString| M | P | | V | Y |
Framed-IPX- 23 6.12.1 UTF8String | M | P | | V | Y |
Network | | | | | |
Framed-Appletalk- 37 6.13.1 Unsigned32 | M | P | | V | Y |
Link | | | | | |
Framed-Appletalk- 38 6.13.2 Unsigned32 | M | P | | V | Y |
Network | | | | | |
Framed-Appletalk- 39 6.13.3 OctetString| M | P | | V | Y |
Zone | | | | | |
ARAP-Features 71 6.14.1 OctetString| M | P | | V | Y |
ARAP-Zone-Access 72 6.14.2 Enumerated | M | P | | V | Y |
Login-IP-Host 14 6.15.1 OctetString| M | P | | V | Y |
Login-IPv6-Host 98 6.15.2 OctetString| M | P | | V | Y |
Login-Service 15 6.15.3 Enumerated | M | P | | V | Y |
Login-TCP-Port 16 6.16.1 Unsigned32 | M | P | | V | Y |
Login-LAT-Service 34 6.17.1 OctetString| M | P | | V | Y |
Login-LAT-Node 35 6.17.2 OctetString| M | P | | V | Y |
Login-LAT-Group 36 6.17.3 OctetString| M | P | | V | Y |
Login-LAT-Port 63 6.17.4 OctetString| M | P | | V | Y |
-----------------------------------------|----+-----+----+-----|----|6.1. Service-Type AVP ✨
Okay bestie, the Service-Type AVP (AVP Code 6) is an Enumerated AVP 🎀, and it's how everybody says what kind of service the user asked for, or what kind is actually getting delivered 💅. One such AVP MAY be present in an authentication and/or authorization request or response 🦋. A NAS doesn't have to implement every single service type, lowkey 🌸. But if it gets an unknown or unsupported Service-Type in a response, it MUST treat that as a failure and end the session with a DIAMETER_INVALID_AVP_VALUE Result-Code 💀.
When it shows up in a request, the Service-Type AVP SHOULD be considered a hint to the server 💜. The NAS is basically saying "hey, I think this user would prefer this kind of service" 🫶. The server doesn't have to honor the hint, though, so don't be shook if it ignores you 🙈. Also, if the service the server picks is supported but doesn't work with the current mode of access, the NAS MUST fail to start the session ✨. The NAS MUST also generate the appropriate error message(s) 😭.
The values defined for the Service-Type AVP are below. The full list lives in [RADIUS] and [RADIUSTypes], and this list is just for vibes ✨ (informational only):
1 Login
2 Framed
3 Callback Login
4 Callback Framed
5 Outbound
6 Administrative
7 NAS Prompt
8 Authenticate Only
9 Callback NAS Prompt
10 Call Check
11 Callback Administrative
12 Voice
13 Fax
14 Modem Relay
15 IAPP-Register [IEEE 802.11f]
16 IAPP-AP-Check [IEEE 802.11f]
17 Authorize Only [RADDynAuth]Now let's get into the ones that get extra detail 👑:
Login 1
The user should be connected to a host. The message MAY
include additional AVPs defined in sections 6.16 or 6.17.
Framed 2
A Framed Protocol, such as PPP or SLIP, should be started for
the User. The message MAY include additional AVPs defined in
section 6.10, or section 7 for tunneling services.
Callback Login 3
The user should be disconnected and called back, then connected
to a host. The message MAY include additional AVPs defined in
this section.
Callback Framed 4
The user should be disconnected and called back, and then a
Framed Protocol, such as PPP or SLIP, should be started for the
User. The message MAY include additional AVPs defined in
section 6.10, or in section 7 for tunneling services.6.2. Callback-Number AVP 📞
The Callback-Number AVP (AVP Code 19) is a UTF8String, and it holds a dialing string for callbacks 🌈. It MAY be used in an authentication and/or authorization request as a hint that the user wants the Callback service 🍓. The server is not required to honor that hint in its response, so no pressure 💅.
How this field's allowed usage range gets written down is outside the scope of this specification 🙈, so that's a problem for another doc, bestie.
6.3. Callback-Id AVP ✨
The Callback-Id AVP (AVP Code 20) is a UTF8String too 🦋. It holds the name of a place to be called, and the NAS is the one that interprets it 🧚. This AVP MAY be present in an authentication and/or authorization response.
Real talk though, this one is NOT roaming-friendly 😬, because it assumes the Callback-Id is already configured on the NAS. So the Callback-Number AVP is therefore preferable 💖.
6.4. Idle-Timeout AVP ⏰
The Idle-Timeout AVP (AVP Code 28) is an Unsigned32 that sets the maximum number of consecutive seconds of idle connection the user is allowed before the session gets terminated or before a prompt gets issued 🌸. The default is none, or system specific 🎀.
6.5. Port-Limit AVP 🔌
The Port-Limit AVP (AVP Code 62) is an Unsigned32 that sets the maximum number of ports the NAS provides to the user 💜. It MAY be used in an authentication and/or authorization request as a hint to the server that multilink PPP [PPPMP] service is desired 🫶. The server is not required to honor the hint in the corresponding response, so it's totally its call 💅.
6.6. NAS-Filter-Rule AVP 🛡️
The NAS-Filter-Rule AVP (AVP Code 400) is an IPFilterRule type, and it gives you filter rules that need to be configured on the NAS for the user 🔥. One or more of these AVPs MAY be present in an authorization response.
6.7. Filter-Id AVP 🏷️
The Filter-Id AVP (AVP Code 11) is a UTF8String that contains the name of the filter list for this user 🦋. Zero or more Filter-Id AVPs MAY be sent in an authorization answer.
Naming a filter list lets you use that filter on different NASes without caring about how each one implements its filter lists 👑. Still, this AVP isn't roaming friendly, because filter naming is different from one service provider to another 😭.
In non-RADIUS environments, it is RECOMMENDED that the NAS-Filter-Rule AVP be used instead 💖.
6.8. Configuration-Token AVP 🧩
The Configuration-Token AVP (AVP Code 78) is an OctetString 🍓. A Diameter Server sends it to a Diameter Proxy Agent or Translation Agent inside an AA-Answer command, to indicate a type of user profile to be used ✨. It should not be sent to a Diameter Client (NAS), so keep it away from the NAS, babe 🙈.
The format of the Data field of this AVP is site specific 🌈.
6.9. QoS-Filter-Rule AVP 🚦
The QoS-Filter-Rule AVP (AVP Code 407) is a QoSFilterRule type 💅, and it provides QoS filter rules that need to be configured on the NAS for the user 🎀. One or more such AVPs MAY be present in an authorization response.
Note: Due to an editorial mistake in [BASE], only the AVP format is discussed. The complete QoSFilterRule definition was not included. It is reprinted here for clarification 🙏.
Here's the QoSFilterRule definition, reprinted so it's actually complete 🧚:
QoSFilterRule
The QosFilterRule format is derived from the OctetString AVP Base
Format. It uses the ASCII charset. Packets may be marked or
metered based on the following information:
Direction (in or out)
Source and destination IP address (possibly masked)
Protocol
Source and destination port (lists or ranges)
DSCP values (no mask or range)
Rules for the appropriate direction are evaluated in order; the
first matched rule terminates the evaluation. Each packet is
evaluated once. If no rule matches, the packet is treated as best
effort. An access device unable to interpret or apply a QoS rule
SHOULD NOT terminate the session.Okay, so the QoS filter rules have a required format 🫶. Here's the shape they MUST follow:
action dir proto from src to dst [options]
tag - Mark packet with a specific DSCP
[DIFFSERV]. The DSCP option MUST be
included.
meter - Meter traffic. The metering options
MUST be included.Here's how the rest of the pieces work 💜:
dirfollows the format described under IPFilterRule.protofollows the format described under IPFilterRule.srcanddstfollow the format described under IPFilterRule.
The options are where the real magic happens ✨:
options:
DSCP <color>
Color values as defined in [DIFFSERV]. Exact
matching of DSCP values is required (no masks or
ranges).
metering <rate> <color_under> <color_over>
The metering option provides Assured Forwarding,
as defined in [DIFFSERVAF], and MUST be present
if the action is set to meter. The rate option is
the throughput, in bits per second, used
by the access device to mark packets. Traffic
over the rate is marked with the color_over
codepoint, and traffic under the rate is marked
with the color_under codepoint. The color_under
and color_over options contain the drop
preferences and MUST conform to the recommended
codepoint keywords described in [DIFFSERVAF]
(e.g., AF13).
The metering option also supports the strict
limit on traffic required by Expedited
Forwarding, as defined in [DIFFSERVEF]. The
color_over option may contain the keyword "drop"
to prevent forwarding of traffic that exceeds the
rate parameter.And last but not least 🌟, the rule syntax is a modified subset of ipfw(8) from FreeBSD, and the ipfw.c code may provide a useful base for implementations 🧚♀️.
6.10. Framed Access Authorization AVPs 🎀
This section lists the authorization AVPs you need to support framed access, like PPP and SLIP 💖. AVPs defined in this section MAY be present in a message if the Service-Type AVP was set to "Framed" or "Callback Framed" 🦋.
6.10.1. Framed-Protocol AVP 🧵
The Framed-Protocol AVP (AVP Code 7) is an Enumerated AVP that contains the framing to be used for framed access 💜. This AVP MAY be present in both requests and responses. The supported values are listed in [RADIUSTypes], and here's the informational list 👑:
1 PPP
2 SLIP
3 AppleTalk Remote Access Protocol (ARAP)
4 Gandalf proprietary SingleLink/MultiLink protocol
5 Xylogics proprietary IPX/SLIP
6 X.75 Synchronous6.10.2. Framed-Routing AVP 🗺️
The Framed-Routing AVP (AVP Code 10) is an Enumerated AVP that contains the routing method for the user when the user is a router to a network 🌈. This AVP SHOULD only be present in authorization responses. The supported values are listed in [RADIUSTypes], and the informational list is here 🍓:
0 None
1 Send routing packets
2 Listen for routing packets
3 Send and Listen6.10.3. Framed-MTU AVP 📦
The Framed-MTU AVP (AVP Code 12) is an Unsigned32 that contains the Maximum Transmission Unit to be configured for the user, when it isn't negotiated by some other means (like PPP) ✨. This AVP SHOULD only be present in authorization responses. The MTU value MUST be in the range from 64 to 65535 🔥.
6.10.4. Framed-Compression AVP 🗜️
The Framed-Compression AVP (AVP Code 13) is an Enumerated AVP that contains the compression protocol to be used for the link 💅. It MAY be used in an authorization request as a hint to the server that a specific compression type is desired, but the server is not required to honor the hint in the corresponding response 🙈.
More than one compression protocol AVP MAY be sent 🫶. The NAS is responsible for applying the proper compression protocol to the appropriate link traffic 💜.
The supported values are listed in [RADIUSTypes]. The informational list goes like this 🎀:
0 None
1 VJ TCP/IP header compression
2 IPX header compression
3 Stac-LZS compression6.11. IP Access Authorization AVPs 🌐
The AVPs defined in this section are used when the user requests access service to IP, or is being granted it 🦋.
6.11.1. Framed-IP-Address AVP 📍
The Framed-IP-Address AVP (AVP Code 8) [RADIUS] is an OctetString that contains an IPv4 address of the type specified in the attribute value, to be configured for the user 💖. It MAY be used in an authorization request as a hint to the server that a specific address is desired, but the server is not required to honor the hint in the corresponding response 🧚.
Two values have special significance, and they're kind of iconic 👑: 0xFFFFFFFF and 0xFFFFFFFE. The value 0xFFFFFFFF means the NAS should let the user pick an address (negotiated) 🌸. The value 0xFFFFFFFE means the NAS should pick an address for the user, like one assigned from a pool of addresses the NAS keeps 🍓.
6.11.2. Framed-IP-Netmask AVP 🎀
okay so the Framed-IP-Netmask AVP (AVP Code 9) is an OctetString, and it carries the four octets of the IPv4 netmask that gets configured for the user when the user is a router to a network 🌐. the user can ask for a netmask in an authorization request as a hint (MAY), but the server doesn't have to honor that hint in its response, so it's a wish, not a guarantee 🙈. the one hard rule: if the request included this AVP with a value of 0xFFFFFFFF, the response MUST include this AVP too 💅
6.11.3. Framed-Route AVP 🦋
the Framed-Route AVP (AVP Code 22) is a UTF8String that holds the ASCII routing info to be set up for the user on the NAS 🛣️. zero or more of these can show up in an authorization response (MAY), and the string itself MUST contain a destination prefix in dotted quad form. you can optionally add a slash and a decimal length to say how many high-order bits of the prefix to use, then a space, a gateway address in dotted quad form, another space, and one or more metrics separated by spaces. example time:
"192.168.1.0/24 192.168.1.1 1"the length part is optional. if you leave it out, it should default to 8 bits for class A prefixes, 16 bits for class B prefixes, and 24 bits for class C prefixes 🧠. like this:
"192.168.1.0 192.168.1.1 1"and here's a lowkey important bit ✨: whenever the gateway address is written as "0.0.0.0", the user's IP address SHOULD be used as the gateway address instead 🫶
6.11.4. Framed-Pool AVP 🌈
the Framed-Pool AVP (AVP Code 88) is an OctetString with the name of an assigned address pool that SHOULD be used to hand out an address to the user 🏊♀️. if the NAS doesn't support multiple address pools, the NAS SHOULD ignore this AVP, no drama. pools are usually for IP addresses, but they can be for other protocols too, as long as the NAS supports pools for those 💜
even though it's typed as OctetString (for compatibility with RADIUS [RADIUSExt]), the encoding of the Data field SHOULD also follow the rules for the UTF8String Data Format. very dual-natured, very iconic 👑
6.11.5. Framed-Interface-Id AVP 🧚
the Framed-Interface-Id AVP (AVP Code 96) is an Unsigned64 holding the IPv6 interface identifier to be configured for the user 🔢. it MAY be used in authorization requests as a hint that a specific interface id is wanted, but the server is not required to honor the hint in the response. wishlist energy again 🎀
6.11.6. Framed-IPv6-Prefix AVP 🌸
the Framed-IPv6-Prefix AVP (AVP Code 97) is an OctetString carrying the IPv6 prefix to be configured for the user 🌐. one or more of these MAY be used in authorization requests as a hint that specific IPv6 prefixes are desired, but the server is not required to honor the hint in its response ✨
6.11.7. Framed-IPv6-Route AVP 💅
the Framed-IPv6-Route AVP (AVP Code 99) is a UTF8String with the ASCII routing info to be set up for the user on the NAS, the IPv6 flavour of Framed-Route 🦋. zero or more can appear in an authorization response (MAY). the string MUST contain an IPv6 address prefix, then a slash and a decimal length specifier saying how many high order bits of the prefix to use. after that comes a space, a gateway address in hexadecimal notation, another space, and one or more metrics separated by spaces. here's the vibe:
"2000:0:0:106::/64 2000::106:a00:20ff:fe99:a998 1"if the gateway address is the IPv6 unspecified address, the user's IP address SHOULD be used as the gateway address instead, such as in:
"2000:0:0:106::/64 :: 1"6.11.8. Framed-IPv6-Pool AVP 🍓
the Framed-IPv6-Pool AVP (AVP Code 100) is an OctetString with the name of an assigned pool that SHOULD be used to assign an IPv6 prefix to the user 🫧. if the access device doesn't support multiple prefix pools, it MUST ignore this AVP. firm but fair 😤
same plot twist as before: it's typed as OctetString for compatibility with RADIUS [RADIUSIPv6], but the encoding of the Data field SHOULD also conform to the rules for the UTF8String Data Format 🙃
6.12. IPX Access 🌸
the AVPs in this section are used when the user requests, or is being granted, access to an IPX network service 🛰️
6.12.1. Framed-IPX-Network AVP 💜
the Framed-IPX-Network AVP (AVP Code 23) is an Unsigned32 with the IPX Network number to be configured for the user 🔢. it MAY be used in an authorization request as a hint that a specific address is desired, but the server is not required to honor the hint in the response.
two addresses are special, and they're iconic 👑: 0xFFFFFFFF means the NAS should let the user pick an address (aka Negotiated), and 0xFFFFFFFE means the NAS should pick one for the user, for example by assigning it from a pool of one or more IPX networks the NAS keeps 🧠
6.13. AppleTalk Network Access 🍎
the AVPs in this section are used when the user requests, or is being granted, access to an AppleTalk network [AppleTalk] 🌈
6.13.1. Framed-AppleTalk-Link AVP ✨
the Framed-AppleTalk-Link AVP (AVP Code 37) is an Unsigned32 with the AppleTalk network number for the serial link to the user, which is another AppleTalk router 🔗. this AVP MUST only be present in an authorization response, and it is never used when the user is not another router. no exceptions, bestie 🫶
despite the size of the field, values range from 0 to 65,535 📏. the special value of 0 means an unnumbered serial link 🌙. a value from 1 to 65,535 means the serial line between the NAS and the user should be assigned that value as an AppleTalk network number 🎀
6.13.2. Framed-AppleTalk-Network AVP 🦋
the Framed-AppleTalk-Network AVP (AVP Code 38) is an Unsigned32 with the AppleTalk Network number that the NAS should probe in order to allocate an AppleTalk node for the user 🔍. this AVP MUST only be present in an authorization response, and it is never used when the user is not another router. multiple instances of this AVP mean the NAS may probe using any of the network numbers listed 🎯
again, values range from 0 to 65,535 📏. the special value 0 means the NAS should assign a network for the user using its default cable range 🧚. a value between 1 and 65,535 (inclusive) tells the AppleTalk Network that the NAS should probe to find an address for the user 💫
6.13.3. Framed-AppleTalk-Zone AVP 🌸
the Framed-AppleTalk-Zone AVP (AVP Code 39) is an OctetString with the AppleTalk Default Zone to be used for this user 🗺️. it MUST only be present in an authorization response, and multiple instances of this AVP in the same message are not allowed. one zone, one vibe 💅
the codification of this field's allowed range is outside the scope of this specification, so we're leaving that one alone 🙈
6.14. AppleTalk Remote Access 🌊
the AVPs in this section are used when the user requests, or is being granted, access to the AppleTalk network via the AppleTalk Remote Access Protocol [ARAP] 📡. they're only present if the Framed-Protocol AVP (see section 6.10.1) is set to ARAP. Section 2.2 of RFC 2869 [RADIUSExt] describes how these attributes are used operationally 📖
6.14.1. ARAP-Features AVP 🎀
the ARAP-Features AVP (AVP Code 71) is an OctetString and MAY be present in the AA-Accept message if the Framed-Protocol AVP is set to the value of ARAP 🪄. see [RADIUSExt] for more on its format ✨
6.14.2. ARAP-Zone-Access AVP 💜
the ARAP-Zone-Access AVP (AVP Code 72) is an Enumerated and MAY be present in the AA-Accept message if the Framed-Protocol AVP is set to the value of ARAP 🍓
the supported values are listed in [RADIUSTypes] and defined in [RADIUSExt] 📋
6.15. Non-Framed Access Authorization AVPs 🖥️
this section has the authorization AVPs needed to support terminal server functionality 💻. AVPs defined here MAY be present in a message if the Service-Type AVP was set to "Login" or "Callback Login" 🔐
6.15.1. Login-IP-Host AVP 🌷
the Login-IP-Host AVP (AVP Code 14) [RADIUS] is an OctetString with the IPv4 address of a host to connect the user to when the Login-Service AVP is included. it MAY be used in an AA-Request command as a hint to the Diameter Server that a specific host is desired, but the Diameter Server is not required to honor the hint in the AA-Answer 🤞
two addresses are special: all ones and 0 🌟. the all-ones value means the NAS SHOULD allow the user to select an address, and the value 0 means the NAS SHOULD select a host to connect the user to 🧠
6.15.2. Login-IPv6-Host AVP 🦄
the Login-IPv6-Host AVP (AVP Code 98) [RADIUSIPv6] is an OctetString with the IPv6 address of a host to connect the user to when the Login-Service AVP is included. it MAY be used in an AA-Request command as a hint to the Diameter Server that a specific host is desired, but the Diameter Server is not required to honor the hint in the AA-Answer 💫
two addresses are special here too 👀:
0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF and 0the value 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF means the NAS SHOULD allow the user to select an address. the value 0 means the NAS SHOULD select a host to connect the user to 🎀
6.15.3. Login-Service AVP 🍒
the Login-Service AVP (AVP Code 15) is an Enumerated with the service that should be used to connect the user to the login host 🔌. this AVP SHOULD only be present in authorization responses.
the supported values are listed in [RADIUSTypes]. the following list is informational, so enjoy it as a cheat sheet 📝:
0 Telnet
1 Rlogin
2 TCP Clear
3 PortMaster (proprietary)
4 LAT
5 X25-PAD
6 X25-T3POS
8 TCP Clear Quiet (suppresses any NAS-generated connect
string)6.16. TCP Services 🌐
the AVPs described in this section MAY be present if the Login-Service AVP is set to Telnet, Rlogin, TCP Clear, or TCP Clear Quiet 🧦
6.16.1. Login-TCP-Port AVP 🔑
the Login-TCP-Port AVP (AVP Code 16) is an Unsigned32 with the TCP port the user is to be connected on when the Login-Service AVP is also present 🚪. this AVP SHOULD only be present in authorization responses. the value MUST NOT be greater than 65,535, so keep it in range, periodt 💯
6.17. LAT Services 🌺
the AVPs described in this section MAY be present if the Login-Service AVP is set to LAT [LAT] ✨
6.17.1. Login-LAT-Service AVP ✨
okay so the Login-LAT-Service AVP (AVP Code 34) is an OctetString 🎀 and it holds the system the user gets connected to by LAT. It MAY be used in an authorization request as a hint that a specific service is wanted, but the server is not required to honor the hint in the response. This AVP MUST only be present in the response if the Login-Service AVP says LAT is desired 💅.
ngl this one is so practical. Admins use it with clustered systems, like a VAX or Alpha cluster 🖥️. In those setups, a bunch of time-sharing hosts share the same resources (disks, printers, etc.), and admins usually set each host up to offer access to each shared resource. So every host in the cluster advertises its services through LAT broadcasts 📣.
Sophisticated users usually know which machines are faster, so they like to use a node name when starting a LAT connection 🏎️. Some admins also want certain users on certain machines as a basic form of load balancing (even though LAT can balance load on its own, lol 💀).
The String field holds the identity of the LAT service to use. The LAT Architecture lets this string contain $ (dollar), - (hyphen), . (period), _ (underscore), numerics, upper- and lowercase alphabetics, and the ISO Latin-1 character set extension [ISOLatin]. All LAT string comparisons are case insensitive 🌸.
6.17.2. Login-LAT-Node AVP ✨
the Login-LAT-Node AVP (AVP Code 35) is an OctetString 🧚 and it holds the Node the user should be automatically connected to by LAT. It MAY be used in an authorization request as a hint that a specific LAT node is wanted, but the server is not required to honor the hint in the response. This AVP MUST only be present in a response if the Login-Service-Type AVP is set to LAT 💜.
The String field holds the identity of the LAT service to use. The LAT Architecture lets this string contain $ (dollar), - (hyphen), . (period), _ (underscore), numerics, upper- and lowercase alphabetics, and the ISO Latin-1 character set extension [ISOLatin]. All LAT string comparisons are case insensitive 🫶.
6.17.3. Login-LAT-Group AVP ✨
the Login-LAT-Group AVP (AVP Code 36) is an OctetString 🌈 and it holds a string that identifies the LAT group codes this user is authorized to use. It MAY be used in an authorization request as a hint that a specific group is wanted, but the server is not required to honor the hint in the response. This AVP MUST only be present in a response if the Login-Service-Type AVP is set to LAT 🔥.
LAT supports 256 different group codes, and LAT uses them as a form of access rights 👑. LAT encodes the group codes as a 256-bit bitmap 🦋.
Admins can assign one or more of the group code bits at the LAT service provider, and that provider will only accept LAT connections that have these group codes set in the bitmap. Admins assign a bitmap of authorized group codes to each user. LAT gets these from the operating system and uses them in its requests to the service providers 🍓.
The codification of the range of allowed usage of this field is outside the scope of this specification. (that's a whole other vibe, not ours to decide here 🙈)
6.17.4. Login-LAT-Port AVP ✨
the Login-LAT-Port AVP (AVP Code 63) is an OctetString 💖 and it holds the Port the user should be connected to by LAT. It MAY be used in an authorization request as a hint that a specific port is wanted, but the server is not required to honor the hint in the response. This AVP MUST only be present in a response if the Login-Service-Type AVP is set to LAT ✨.
The String field holds the identity of the LAT service to use. The LAT Architecture lets this string contain $ (dollar), - (hyphen), . (period), _ (underscore), numerics, upper- and lower-case alphabetics, and the ISO Latin-1 character set extension [ISOLatin]. All LAT string comparisons are case insensitive 💅.
7. NAS Tunneling 🦋
okay this section is giving secret tunnel energy 🕵️♀️. Some NASes support compulsory tunnel services, where the incoming connection data gets wrapped up with an encapsulation method and sent to a gateway somewhere else in the network 🎁. This is usually invisible to the service user, and the remote AAA server can describe the tunnel characteristics based on the user's authorization information. Several tunnel characteristics may come back, and the NAS implementation may choose one [RADTunnels], [RADTunlAcct] 💜.
Here's the whole attribute lineup with its flag rules (the table is in code, so it stays exactly as the original has it 🫶):
+---------------------+
| AVP Flag rules |
|----+-----+----+-----|----+
AVP Section | | |SHLD| MUST| |
Attribute Name Code Defined Value Type |MUST| MAY | NOT| NOT |Encr|
-----------------------------------------|----+-----+----+-----|----|
Tunneling 401 7.1 Grouped | M | P | | V | N |
Tunnel-Type 64 7.2 Enumerated | M | P | | V | Y |
Tunnel-Medium- 65 7.3 Enumerated | M | P | | V | Y |
Type | | | | | |
Tunnel-Client- 66 7.4 UTF8String | M | P | | V | Y |
Endpoint | | | | | |
Tunnel-Server- 67 7.5 UTF8String | M | P | | V | Y |
Endpoint | | | | | |
Tunnel-Password 69 7.6 OctetString| M | P | | V | Y |
Tunnel-Private- 81 7.7 OctetString| M | P | | V | Y |
Group-Id | | | | | |
Tunnel- 82 7.8 OctetString| M | P | | V | Y |
Assignment-Id | | | | | |
Tunnel-Preference 83 7.9 Unsigned32 | M | P | | V | Y |
Tunnel-Client- 90 7.10 UTF8String | M | P | | V | Y |
Auth-Id | | | | | |
Tunnel-Server- 91 7.11 UTF8String | M | P | | V | Y |
Auth-Id | | | | | |
-----------------------------------------|----+-----+----+-----|----|7.1. Tunneling AVP 🎀
the Tunneling AVP (AVP Code 401) is a Grouped type 🧁 and it contains the following AVPs, used to describe a compulsory tunnel service [RADTunnels], [RADTunlAcct]. Its data field has this ABNF grammar:
Tunneling ::= < AVP Header: 401 >
{ Tunnel-Type }
{ Tunnel-Medium-Type }
{ Tunnel-Client-Endpoint }
{ Tunnel-Server-Endpoint }
[ Tunnel-Preference ]
[ Tunnel-Client-Auth-Id ]
[ Tunnel-Server-Auth-Id ]
[ Tunnel-Assignment-Id ]
[ Tunnel-Password ]
[ Tunnel-Private-Group-Id ]7.2. Tunnel-Type AVP 🌊
the Tunnel-Type AVP (AVP Code 64) is an Enumerated type and it holds the tunneling protocol(s) to be used (for a tunnel initiator) or in use (for a tunnel terminator) 🚇. It MAY be used in an authorization request as a hint that a specific tunnel type is wanted, but the server is not required to honor the hint in the response.
The Tunnel-Type AVP SHOULD also be included in Accounting-Request messages 📊.
a tunnel initiator is not required to implement any of these tunnel types 🙌. If a tunnel initiator gets a response that contains only unknown or unsupported Tunnel-Types, the tunnel initiator MUST behave as though a response were received with the Result-Code indicating a failure. harsh but fair 💀.
The supported values are listed in [RADIUSTypes]. The following list is informational:
1 Point-to-Point Tunneling Protocol (PPTP)
2 Layer Two Forwarding (L2F)
3 Layer Two Tunneling Protocol (L2TP)
4 Ascend Tunnel Management Protocol (ATMP)
5 Virtual Tunneling Protocol (VTP)
6 IP Authentication Header in the Tunnel-mode (AH)
7 IP-in-IP Encapsulation (IP-IP)
8 Minimal IP-in-IP Encapsulation (MIN-IP-IP)
9 IP Encapsulating Security Payload in the Tunnel-mode (ESP)
10 Generic Route Encapsulation (GRE)
11 Bay Dial Virtual Services (DVS)
12 IP-in-IP Tunneling
13 Virtual LANs (VLAN)7.3. Tunnel-Medium-Type AVP 🍭
the Tunnel-Medium-Type AVP (AVP Code 65) is an Enumerated type and it holds the transport medium to use when creating a tunnel for protocols (like L2TP) that can run over multiple transports 🛤️. It MAY be used in an authorization request as a hint that a specific medium is wanted, but the server is not required to honor the hint in the response.
The supported values are listed in [RADIUSTypes]. The following list is informational:
1 IPv4 (IP version 4)
2 IPv6 (IP version 6)
3 NSAP
4 HDLC (8-bit multidrop)
5 BBN 1822
6 802 (includes all 802 media plus Ethernet "canonical
format")
7 E.163 (POTS)
8 E.164 (SMDS, Frame Relay, ATM)
9 F.69 (Telex)
10 X.121 (X.25, Frame Relay)
11 IPX
12 Appletalk
13 Decnet IV
14 Banyan Vines
15 E.164 with NSAP format subaddress7.4. Tunnel-Client-Endpoint AVP 🌷
the Tunnel-Client-Endpoint AVP (AVP Code 66) is a UTF8String 🫧 and it holds the address of the initiator end of the tunnel. It MAY be used in an authorization request as a hint that a specific endpoint is wanted, but the server is not required to honor the hint in the response.
This AVP SHOULD be included in the corresponding Accounting-Request messages, and then it shows the address the tunnel was started from 📍. This AVP, along with the Tunnel-Server-Endpoint and Session-Id AVP [BASE], MAY be used to provide a globally unique way to identify a tunnel for accounting and auditing purposes 🕵️♀️.
If Tunnel-Medium-Type is IPv4 (1), this string is either the fully qualified domain name (FQDN) of the tunnel client machine, or a "dotted-decimal" IP address. Implementations MUST support the dotted-decimal format and SHOULD support the FQDN format for IP addresses 🔢.
If Tunnel-Medium-Type is IPv6 (2), this string is either the FQDN of the tunnel client machine, or a text representation of the address in either the preferred or alternate form [IPv6Addr]. Conforming implementations MUST support the preferred form and SHOULD support both the alternate text form and the FQDN format for IPv6 addresses 🌌.
If Tunnel-Medium-Type is neither IPv4 nor IPv6, this string is a tag that refers to configuration data local to the Diameter client, describing the interface or medium-specific client address to use 🧩.
7.5. Tunnel-Server-Endpoint AVP 🦋
okay bestie, the Tunnel-Server-Endpoint AVP (AVP Code 67) is a UTF8String 💅 and it holds the address of the server end of the tunnel 🌸 It MAY show up in an authorization request as a hint, basically saying "hey server, I'd lowkey love this specific endpoint," but the server doesn't have to honor the hint in its response 🫶
This AVP SHOULD be included in the matching Accounting-Request messages 📊 and in that case it tells you the address the tunnel was started from ✨ Together with Tunnel-Client-Endpoint and the Session-Id AVP [BASE], it MAY be used to create a globally unique way to identify a tunnel for accounting and auditing. no cap, that's so iconic 👑
If Tunnel-Medium-Type is IPv4 (1), the string is either the fully qualified domain name (FQDN) of the tunnel server machine, or a "dotted-decimal" IP address 🍓 Implementations MUST support the dotted-decimal format and SHOULD support the FQDN format for IP addresses 💜
If Tunnel-Medium-Type is IPv6 (2), the string is either the FQDN of the tunnel server machine, or a text representation of the address in either the preferred or alternate form [IPv6Addr] 🌈 Implementations MUST support the preferred form and SHOULD support both the alternate text form and the FQDN format for IPv6 addresses 🧚
If Tunnel-Medium-Type is neither IPv4 nor IPv6, the string is a tag that points to configuration data local to the Diameter client. That data describes the interface or the medium-specific server address to use ⭐
7.6. Tunnel-Password AVP 🔥
The Tunnel-Password AVP (AVP Code 69) is an OctetString and may hold a password used to authenticate to a remote server 🔐 This one has sensitive info in it, so be careful 😭 It is not protected the same way RADIUS does it [RADTunnels].
As required in [BASE], Diameter messages are encrypted using IPsec or TLS 🔒 The Tunnel-Password AVP SHOULD NOT be used in untrusted proxy environments unless you encrypt it with end-to-end security techniques, such as CMS Security [DiamCMS] 💀
Not gonna lie, this is the one to be extra paranoid about. Don't leave your password just floating around in an untrusted proxy 🙈
7.7. Tunnel-Private-Group-Id AVP 🌸
The Tunnel-Private-Group-Id AVP (AVP Code 81) is an OctetString and holds the group Id for one particular tunneled session 🎀 It MAY be included in an authorization request if the tunnel initiator can predetermine the group that a given connection will end up in 🔮 It SHOULD be included in the authorization response if the tunneled session is supposed to be treated as part of a particular private group 💖
Private groups are used to link a tunneled session with a specific group of users 👯 For example, it MAY be used to help route unregistered IP addresses through a particular interface 🛣️ This AVP SHOULD be included in the Accounting-Request messages about the tunneled session 📊
7.8. Tunnel-Assignment-Id AVP 🦋
The Tunnel-Assignment-Id AVP (AVP Code 82) is an OctetString used to tell the tunnel initiator which tunnel a session should be assigned to 🎯 Some tunneling protocols, like [PPTP] and [L2TP], let sessions between the same two tunnel endpoints get multiplexed over one tunnel, and they also let a given session have its own dedicated tunnel 🧩 This attribute gives Diameter a way to tell the tunnel initiator (for example, a PAC or a LAC) whether to put the session in a multiplexed tunnel or a separate one 🫧 It also lets sessions that share multiplexed tunnels be assigned to different multiplexed tunnels 💅
Different tunnels can be given different characteristics by a tunneling implementation 💫 For example, different tunnels might get different QoS parameters 🚀 Those tunnels could carry one session or several 🌈 So the Tunnel-Assignment-Id attribute lets the Diameter server say "put this session on a tunnel with the right level of service" ✨ Any QoS-related Diameter tunneling attributes defined in the future that go with this one are expected to be linked by the tunnel initiator to the Id given in this attribute 🔗 Until then, what any particular Id string means is up to local configuration in the tunnel initiator 🛠️
The Tunnel-Assignment-Id AVP only matters to Diameter and the tunnel initiator 🙅♀️ The Id it carries is only meant for local use between Diameter and the tunnel initiator 🏠 The Id the tunnel initiator assigns is not passed on to the tunnel peer 🤫
This attribute MAY be included in authorization responses 💌 A tunnel initiator that receives it MAY choose to ignore it and put the session into any arbitrary multiplexed or non-multiplexed tunnel between the desired endpoints 🎲 The AVP SHOULD also be included in the Accounting-Request messages about the tunneled session 📝
If a tunnel initiator supports the Tunnel-Assignment-Id AVP, it should assign a session to a tunnel like this 👇
- If this AVP is present and a tunnel already exists between the specified endpoints with the specified Id, the session should be assigned to that tunnel ✅
- If this AVP is present and no tunnel exists between the specified endpoints with the specified Id, a new tunnel should be established for the session, and the specified Id should be associated with that new tunnel 🆕
- If this AVP is not present, the session is assigned to an unnamed tunnel 🫥 If an unnamed tunnel doesn't exist yet between the specified endpoints, it gets established and used for this session and for later sessions set up without the Tunnel-Assignment-Id attribute 🌱 A tunnel initiator MUST NOT assign a session that didn't specify a Tunnel-Assignment-Id AVP to a named tunnel (meaning one that was started by a session specifying this AVP) 🚫
Note that the same Id can be used to name different tunnels, as long as those tunnels are between different endpoints 🧚♀️
7.9. Tunnel-Preference AVP 👑
The Tunnel-Preference AVP (AVP Code 83) is an Unsigned32 used to show the relative preference of each tunnel when more than one set of tunneling AVPs comes back in separate Grouped-AVP AVPs 🏆 It MAY be used in an authorization request as a hint that a specific preference is wanted, but the server is not required to honor the hint in its response 💭
Here's an example, bestie 🎀 Suppose the server sends back AVPs describing two tunnels: one with a Tunnel-Type of PPTP and one with a Tunnel-Type of L2TP 🌷 If the tunnel initiator only supports one of the Tunnel-Types returned, it starts a tunnel of that type 🫶 But if it supports both tunnel protocols, it SHOULD use the value of the Tunnel-Preference AVP to decide which tunnel to start 🧠 The tunnel with the lowest numerical value in this AVP's Value field SHOULD be given the highest preference 📉 Two or more instances of the Tunnel-Preference AVP inside one authorization response MAY have identical values 🪞 When that happens, the tunnel initiator SHOULD use locally configured metrics to decide which set of AVPs to use 📏
7.10. Tunnel-Client-Auth-Id AVP 🪪
The Tunnel-Client-Auth-Id AVP (AVP Code 90) is a UTF8String that names the name the tunnel initiator used during the authentication phase of tunnel setup 🙋♀️ It MAY be used in an authorization request as a hint that a specific preference is desired, but the server is not required to honor the hint in the corresponding response 💌 This AVP MUST be present in the authorization response if an authentication name other than the default is wanted 🚨 This AVP SHOULD be included in the Accounting-Request messages about the tunneled session 📊
7.11. Tunnel-Server-Auth-Id AVP 🧁
The Tunnel-Server-Auth-Id AVP (AVP Code 91) is a UTF8String that names the name the tunnel terminator used during the authentication phase of tunnel setup 🏰 It MAY be used in an authorization request as a hint that a specific preference is desired, but the server is not required to honor the hint in the corresponding response 🌟 This AVP MUST be present in the authorization response if an authentication name other than the default is wanted 🚨 This AVP SHOULD be included in the Accounting-Request messages about the tunneled session 📝
8. NAS Accounting 📊
Applications that implement this specification use Diameter Accounting, as defined in [BASE], plus the AVPs in the following section 💖 Service-specific AVP usage is defined in the tables in section 10 📋
If accounting is active, Accounting Request (ACR) messages SHOULD be sent after the completion of any Authentication or Authorization transaction, and at the end of a Session 🏁 The Accounting-Record-Type value tells you what kind of event it is 🏷️ All the other AVPs identify the session and give extra info about the event 🔍
Successfully completing the first Authentication or Authorization transaction SHOULD cause a START_RECORD to be sent 🎬 If more Authentications or Authorizations happen in later transactions, the first exchange should generate a START_RECORD, and the later ones an INTERIM_RECORD 🔁 For a given session, there MUST only be one set of matching START and STOP records, with any number of INTERIM_RECORDS in between, or one EVENT_RECORD explaining why a session wasn't started 🫠
Here's the table describing the AVPs, their AVP Code values, types, and possible flag values, and whether the AVP MAY be encrypted 🧾
+---------------------+
| AVP Flag rules |
|----+-----+----+-----|----+
AVP Section | | |SHLD| MUST| |
Attribute Name Code Defined Value Type |MUST| MAY | NOT| NOT|Encr|
-----------------------------------------|----+-----+----+-----|----|
Accounting- 363 8.1 Unsigned64 | M | P | | V | Y |
Input-Octets | | | | | |
Accounting- 364 8.2 Unsigned64 | M | P | | V | Y |
Output-Octets | | | | | |
Accounting- 365 8.3 Unsigned64 | M | P | | V | Y |
Input-Packets | | | | | |
Accounting- 366 8.4 Unsigned64 | M | P | | V | Y |
Output-Packets | | | | | |
Acct-Session-Time 46 8.5 Unsigned32 | M | P | | V | Y |
Acct-Authentic 45 8.6 Enumerated | M | P | | V | Y |
Acounting-Auth- 406 8.7 Enumerated | M | P | | V | Y |
Method | | | | | |
Acct-Delay-Time 41 8.8 Unsigned32 | M | P | | V | Y |
Acct-Link-Count 51 8.9 Unsigned32 | M | P | | V | Y |
Acct-Tunnel- 68 8.10 OctetString| M | P | | V | Y |
Connection | | | | | |
Acct-Tunnel- 86 8.11 Unsigned32 | M | P | | V | Y |
Packets-Lost | | | | | |
-----------------------------------------|----+-----+----+-----|----|8.1. Accounting-Input-Octets AVP 💖
okay so the Accounting-Input-Octets AVP (AVP Code 363) is an Unsigned64 and it counts the octets received from the user 📊✨
for NAS usage, it tells you how many octets came in through the port during the session 🔌 and it can ONLY show up in ACR messages whose Accounting-Record-Type is INTERIM_RECORD or STOP_RECORD. no other record types, bestie 🙅♀️
8.2. Accounting-Output-Octets AVP 🦋
the Accounting-Output-Octets AVP (AVP Code 364) is an Unsigned64 that counts the octets sent to the user, and it's giving the mirror image of the input one 🪞
for NAS usage, it shows how many octets went out to the port during the session. same rule applies: it can only be in ACR messages with an Accounting-Record-Type of INTERIM_RECORD or STOP_RECORD 💅
8.3. Accounting-Input-Packets AVP 🎀
the Accounting-Input-Packets AVP (AVP Code 365) is an Unsigned64 and it counts the packets received from the user 📦
for NAS usage, this one counts how many packets came in through the port over a session that's being provided to a Framed User 🌸 and, same as always, it can only show up in ACR messages with an Accounting-Record-Type of INTERIM_RECORD or STOP_RECORD 🙈
8.4. Accounting-Output-Packets AVP 🍓
the Accounting-Output-Packets AVP (AVP Code 366) is an Unsigned64 that counts the IP packets sent to the user 🚀
for NAS usage, it counts how many packets went out to the port over a session being provided to a Framed User. and yep, it can only be in ACR messages with an Accounting-Record-Type of INTERIM_RECORD or STOP_RECORD 🫶
8.5. Acct-Session-Time AVP ⏰
the Acct-Session-Time AVP (AVP Code 46) is an Unsigned32 and it tells you how long the current session has been going, in seconds 🕰️ it can only be in ACR messages with an Accounting-Record-Type of INTERIM_RECORD or STOP_RECORD, so don't try to sneak it into the others 😤
8.6. Acct-Authentic AVP 🔐
the Acct-Authentic AVP (AVP Code 45) is an Enumerated type and it says how the user got authenticated 🪪 the supported values live in [RADIUSTypes], and the list below is just for vibes (informational only) ✨
1 RADIUS
2 Local
3 Remote
4 Diameter8.7. Accounting-Auth-Method AVP 🧚
the Accounting-Auth-Method AVP (AVP Code 406) is an Enumerated type. a NAS MAY include this AVP in an Accounting-Request message to show which method was used to authenticate the user 💜 (fun fact: this is basically the same thing as the RADIUS MS-Acct-Auth-Type VSA attribute, so if you know that one, you already know this one 🙌)
these are the values that are defined:
1 PAP
2 CHAP
3 MS-CHAP-1
4 MS-CHAP-2
5 EAP
7 None8.8. Acct-Delay-Time 🕰️
the Acct-Delay-Time AVP (AVP Code 41) is an Unsigned32 and it says how many seconds the Diameter client has been trying to send the Accounting-Request (ACR) 📨 the accounting server can subtract this number from the time the ACR shows up at the server, and that gives a rough idea of when the event that made the ACR actually happened 🕵️♀️
this AVP is NOT used for retransmissions at the transport level (TCP or SCTP), so don't mix those up 🙅♀️ instead, it's for when an ACR can't be sent because there's no appropriate peer to send it to, or it got rejected because it couldn't be delivered 📭 in those cases the command MAY be buffered and sent later, either when a good peer-connection shows up or after enough time has passed that the destination-host might be reachable and running again ⏳ and if the ACR gets resent like this, the Acct-Delay-Time AVP SHOULD be included 💅 its value is the number of seconds that passed between the first attempt and the current one 🎀
8.9. Acct-Link-Count 🔗
the Acct-Link-Count AVP (AVP Code 51) is an Unsigned32 and it's the total number of links that have been active (current or closed) in a given multilink session when the accounting record gets made 🧩 this AVP MAY be included in Accounting-Requests for any session that could be part of a multilink service 💖
it helps the accounting server figure out when it has ALL the records for a multilink service 🕵️♀️ when the number of Accounting-Requests received with Accounting-Record-Type = STOP_RECORD (sharing the same Acct-Multi-Session-Id and unique Session-Ids) equals the biggest Acct-Link-Count value seen in those requests, then every STOP_RECORD Accounting-Request for that multilink service has arrived 🎉
here's an example with eight Accounting-Requests so you can see how Acct-Link-Count works. the table only shows the relevant AVPs, even though the Accounting-Requests will have more accounting info in them 🌈
Acct-Multi- Accounting- Acct-
Session-Id Session-Id Record-Type Link-Count
--------------------------------------------------------
"...10" "...10" START_RECORD 1
"...10" "...11" START_RECORD 2
"...10" "...11" STOP_RECORD 2
"...10" "...12" START_RECORD 3
"...10" "...13" START_RECORD 4
"...10" "...12" STOP_RECORD 4
"...10" "...13" STOP_RECORD 4
"...10" "...10" STOP_RECORD 48.10. Acct-Tunnel-Connection AVP 🚇
the Acct-Tunnel-Connection AVP (AVP Code 68) is an OctetString that holds the identifier assigned to the tunnel session 🧾 this AVP, together with the Tunnel-Client-Endpoint and Tunnel-Server-Endpoint AVPs, can be used to uniquely identify a tunnel session for auditing purposes 🔍
the format of the identifier depends on the value of the Tunnel-Type AVP 🎭 for example, to fully identify an L2TP tunnel connection, the L2TP Tunnel Id and Call Id might get encoded in this field 🧚 the exact encoding is implementation dependent, so it's up to each implementation to decide 🤷♀️
8.11. Acct-Tunnel-Packets-Lost AVP 📉
the Acct-Tunnel-Packets-Lost AVP (AVP Code 86) is an Unsigned32 and it holds the number of packets lost on a given link 💀
9. RADIUS/Diameter Protocol Interactions 🌉
okay, this section is all about basic guidelines that servers acting as AAA Translation Agents may use 🪄 a full description of every single difference between RADIUS and Diameter is way beyond what this section (and this document) covers 📚 also, this document doesn't stop implementations from making extra translation methods, as long as the translation doesn't break the RADIUS or Diameter protocols 🙌
so, Diameter is basically a superset of RADIUS functions in lots of ways, BUT a bunch of RADIUS representations are NOT allowed so that new capabilities can be used without bringing the old problems along 🎀 hmm, wait, let me say that with the right caps: a number of RADIUS representations are not allowed, full stop 🙅♀️
there are two main situations you have to handle 💅 the first is when a RADIUS request comes in and has to be forwarded as a Diameter request. the second is the reverse of that 🔄 RADIUS doesn't support a peer-to-peer architecture, and server-initiated operations are generally not supported either 🙃 if you want an alternative, check out [RADDynAuth] 🦋
some RADIUS attributes are encrypted 🔐 RADIUS security and encryption techniques are applied on a hop-per-hop basis, so a Diameter agent will have to decrypt RADIUS attribute data as it enters the Diameter system 😭 and if that info gets forwarded, the agent MUST secure it by using Diameter specific techniques 🛡️🔥 this is NOT optional, bestie, do not skip it 💀
one more thing: this section uses the two terms, "AVP" and "attribute", in a concise and specific way ✨ "AVP" means a Diameter AVP, and "attribute" means a RADIUS attribute 🫶
9.1. RADIUS Request Forwarded as Diameter Request
okay bestie, this part is the playbook for what a Translation Agent does when a RADIUS message shows up and needs to become a Diameter message 🦋
first, the tea ☕ RADIUS servers are assumed to be stateless 💀 and it's totally possible for the authentication and accounting messages in one session to get handled by different Translation Agents in the proxy network 😭 so a RADIUS/Diameter Translation Agent SHOULD NOT be assumed to have an accurate track on session-state information 🙈
when a Translation Agent gets a RADIUS message, here's the checklist 💅
- If a
Message-Authenticatorattribute is present, the value MUST be checked but not included in the Diameter message 🔐 If it's incorrect, the RADIUS message should be silently discarded 🤫 The gateway system SHOULD generate and include aMessage-Authenticatorin returned RADIUS responses ✨ - The transport address of the sender MUST be checked against the NAS identifying attributes 👀 (see
NAS-IdentifierandNAS-IP-Addressbelow) - The Translation Agent must maintain transaction state information for the RADIUS request, like the
Identifierfield in the RADIUS header, any existing RADIUSProxy-Stateattribute, and the source IP address and port number of the UDP packet 🧠 This can live in a local state table or get saved in aProxy-InfoAVP group. A DiameterSession-IdAVP value must be created using a session state mapping mechanism 🎀 - If the RADIUS request contained a
Stateattribute and the prefix of the data is"Diameter/", the data after the prefix holds the DiameterOrigin-Host/Origin-Realm/Session-Id. If none of those are present and the RADIUS command is anAccess-Request, a new Session-Id is created 🪄 The Session-Id goes in theSession-IdAVP. - The Diameter
Origin-HostandOrigin-RealmAVPs MUST be created and added using the information from an FQDN corresponding to theNAS-IP-Addressattribute (preferred if available), and/or to theNAS-Identifierattribute. (Fun fact: the RADIUSNAS-Identifieris not required to be an FQDN 🤓) - The response MUST have an
Origin-AAA-ProtocolAVP added, indicating the protocol of origin of the message 🏷️ - The
Proxy-Infogroup SHOULD be added, with the local server's identity specified in theProxy-HostAVP. This should make sure the response gets sent back to this system 📬 - The
Destination-RealmAVP is created from the information found in the RADIUSUser-Nameattribute 💌 - If the RADIUS
User-Passwordattribute is present, the password must be unencrypted using the link's RADIUS shared secret 🔓 The unencrypted value must then be forwarded in aUser-PasswordAVP using Diameter security 🔒 - If the RADIUS
CHAP-Passwordattribute is present, the Ident and Data portion of the attribute are used to create theCHAP-Authgrouped AVP 🧁 - If the RADIUS message contains an address attribute, it MUST be converted to the appropriate Diameter AVP and type 🗺️
- If the RADIUS message contains Tunnel information [RADTunnels], the attributes or tagged groups should each be converted to a Diameter Tunneling Grouped AVP set 🚇 If the tunnel info has a
Tunnel-Passwordattribute, the RADIUS encryption must be resolved, and the password forwarded, using Diameter security methods 🔐 - If the RADIUS message is an
Accounting-Request, theAcct-Status-Typeattribute value must be converted to anAccounting-Record-TypeAVP value 📊 If theAcct-Status-Typeattribute value isSTOP, the local server MUST issue aSession-Termination-Requestmessage once the DiameterAccounting-Answermessage has been received 🛑 - If the Accounting message contains an
Acct-Termination-Causeattribute, it should be translated to the equivalentTermination-CauseAVP value (see below) 🙋 - If the RADIUS message contains
Accounting-Input-Octets,Accounting-Input-Packets,Accounting-Output-Octets, orAccounting-Output-Packets, these attributes must be converted to the Diameter equivalents 🔢 Also, if theAcct-Input-GigawordsorAcct-Output-Gigawordsattributes are present, these must be used to properly compute the Diameter accounting AVPs 🧮
okay now the way back 🔙 The corresponding Diameter response is always guaranteed to be received by the same Translation Agent that translated the original request, thanks to the contents of the Proxy-Info AVP group in the Diameter request 💖 These steps get applied to the response during the Diameter-to-RADIUS translation:
- If the Diameter Command-Code is set to
AA-Answerand theResult-CodeAVP is set toDIAMETER_MULTI_ROUND_AUTH, the gateway must send a RADIUSAccess-Challenge🌀 It must have theOrigin-Host,Origin-Realm, and DiameterSession-IdAVPs encapsulated in the RADIUSStateattribute, with the prefix"Diameter/", concatenated in that order and separated with"/"characters, in UTF-8 [UTF-8] 🧵 This is what makes sure the Translation Agent receiving the next RADIUSAccess-Requesthas the Session Identifier and can set the Destination-Host to the correct value 🎯 If theMulti-Round-Time-OutAVP is present, its value MUST be inserted in the RADIUSSession-TimeoutAVP ⏰ - If the Command-Code is set to
AA-Answer, the DiameterSession-IdAVP is saved in a new RADIUSClassattribute whose format is the string"Diameter/"followed by the Diameter Session Identifier 💾 This way, any later Accounting messages, which could be received by any Translation Agent, still have access to the original Diameter Session Identifier 🫶 - If a
Proxy-Stateattribute was present in the RADIUS request, the same attribute gets added to the response 🔁 This info may be found in theProxy-InfoAVP group, or in a local state table. - If state info about the RADIUS request was saved in a
Proxy-InfoAVP or local state table, the RADIUSIdentifierand UDP IP Address and port number are pulled out and used when sending the RADIUS reply 🏁
when translating a Diameter AA-Answer (with a successful result code) into a RADIUS Access-Accept that contains a Session-Timeout or Authorization-Lifetime AVP, do these steps 🧚
- If the Diameter message has a
Session-TimeoutAVP but noAuthorization-LifetimeAVP, translate it to aSession-Timeoutattribute (not aTermination-Action) ⏳ - If the Diameter message has an
Authorization-LifetimeAVP but noSession-TimeoutAVP, translate it to aSession-Timeoutattribute and aTermination-Actionset toAA-REQUEST. (RemoveAuthorization-LifetimeandRe-Auth-Request-Type.) 🧹 - If the Diameter message has both, the Session-Timeout must be greater than or equal to the Authorization-Lifetime (required by [BASE]). Translate it to a
Session-Timeoutvalue (taking the value from theAuthorization-LifetimeAVP, the smaller one) and set theTermination-ActiontoAA-REQUEST. (Remove theAuthorization-LifetimeandRe-Auth-Request-Type.) 💅
9.1.1. RADIUS Dynamic Authorization Considerations
okay so a Diameter/RADIUS gateway might talk to a server that implements RADIUS Dynamic Authorization [RADDynAuth] 🎧 If the server supports these functions, it MUST be listening on the assigned port, and it would receive RADIUS CoA-Request and Disconnect-Request messages 📥 These can get mapped into the Diameter Re-Auth-Request (RAR) and Abort-Session-Request (ASR) message exchanges, respectively [BASE] 🔄
if [RADDynAuth] is not supported, the port wouldn't be active and the RADIUS server would receive an ICMP Port Unreachable indication 🙅♀️ Or, if the messages do arrive but with an inappropriate Service-Type, the gateway can respond with the appropriate NAK message and an Error-Cause attribute with the value of 405, "Unsupported Service" 🚫
the RADIUS CoA-Request and Disconnect-Request messages won't contain a Diameter Session-Id 😭 Diameter requires that this value match an active session context, so the gateway MUST have a session Id cache (or other means) to identify the sessions these functions pertain to 🗂️ If it can't identify the session, the gateway (or NAS) should return an Error-Cause value of 503, "Session Context Not Found" 🫠
the RADIUS CoA-Request message only supports a change of authorization attributes, and the received CoA-Request SHOULD include a Service-Type of "Authorize-Only" ✨ This indicates an extended exchange request by the rules given in [RADDynAuth] section 3.2, note 6. It's also the only type of exchange Diameter supports [BASE] 👑
for the CoA-Request, the translated RAR message will have a Re-Auth-Type of AUTHORIZE_ONLY 🎀 The returned RAA gets translated into a CoA-NAK with Error-Cause "Request Initiated" 🙃 The gateway's Diameter client SHOULD also start a reauthorization sequence by sending an AAR message, which gets translated into an Access-Request message 🔁 The RADIUS server uses the Access-Accept (or Access-Reject) message to convey the new authorization attributes, which the gateway passes back in an AAA message 🦋
any attributes included in the COA-Request or Access-Accept message are to be considered mandatory in Diameter 🧱 If they can't be supported, they MUST result in an error message return to the RADIUS server, with an Error-Cause of "Unsupported Attribute" 🚨 The Diameter NAS will attempt to apply all the attributes supplied in the AA message to the session 🫡
last but not least 💖 a RADIUS Disconnect-Request message received by the gateway gets translated to a Diameter Abort-Session-Request (ASR) message [BASE] 👋 The results come back from the Diameter client in an Abort-Session-Answer (ASA) message. A success indication translates to a RADIUS Disconnect-ACK, and a failure generates a Disconnect-NAK 🌸
9.2. Diameter Request Forwarded as RADIUS Request 🎀
okay so this section is about what happens when a server gets a Diameter request that needs to be forwarded to a RADIUS entity 🦋 the steps below are examples of what may be done:
- The Origin-Host AVP's value is inserted into the NAS-Identifier attribute.
- The following information MUST be present in the corresponding Diameter response and therefore MUST be saved, either in a local state table or encoded in a RADIUS Proxy-State attribute:
- Origin-Host AVP
- Session-Id AVP
- Proxy-Info AVP
- Any other AVP that MUST be present in the response and has no corresponding RADIUS attribute.
- If the CHAP-Auth AVP is present, the grouped AVPs are used to create the RADIUS CHAP-Password attribute data. 🔐
- If the User-Password AVP is present, the data should be encrypted and forwarded by using RADIUS rules. The same is true for any other RADIUS-encrypted attribute values. 💅
- AVPs of the type Address must be translated to the corresponding RADIUS attribute. 🌸
- If the Accounting-Input-Octets, Accounting-Input-Packets, Accounting-Output-Octets, or Accounting-Output-Packets AVPs are present, they must be translated to the corresponding RADIUS attributes. If the value of the Diameter AVPs does not fit within a 32-bit RADIUS attribute, the RADIUS Acct-Input-Gigawords and Acct-Output-Gigawords must be used. 📊
- If the RADIUS link supports the Message-Authenticator attribute [RADIUSExt], it SHOULD be generated and added to the request. ✨
When the Translation Agent gets the corresponding response, which RADIUS guarantees will happen 🫶, the following steps may be taken:
- If the RADIUS code is set to Access-Challenge, a Diameter AA-Answer message is created with the Result-Code set to
DIAMETER_MULTI_ROUND_AUTH. If the Session-Timeout AVP is present in the RADIUS message, its value is inserted into the Multi-Round-Time-Out AVP. ⏰ - If a Proxy-State attribute is present, extract the encoded information. Otherwise, retrieve the original Proxy-Info AVP group information from the local state table.
- The response's Origin-Host information is created from the FQDN of the RADIUS message's source IP address. The same FQDN is also stored in a Route-Record AVP. 🗺️
- The response's Destination-Host AVP is copied from the saved request's Origin-Host information.
- The Session-Id information can be recovered from local state, or from the constructed State or Proxy-State attribute, as above.
- If a Proxy-Info AVP was present in the request, the same AVP MUST be added to the response. 👑
- If the RADIUS State attributes are present, they must be present in the Diameter response, minus those added by the gateway.
- Any other AVPs that were saved at request time, and that MUST be present in the response, are added to the message. 💖
When translating a RADIUS Access-Accept to a Diameter AA-Answer that contains a Session-Timeout attribute, do the following:
- If the RADIUS message contains a Session-Timeout attribute and a Termination-Action attribute set to DEFAULT (or no Termination-Action attribute at all), translate it to an AA-Answer with a Session-Timeout AVP and remove the Termination-Action attribute.
- If the RADIUS message contains a Session-Timeout attribute and a Termination-Action attribute set to AA-REQUEST, translate it to an AA-Answer with an Authorization-Lifetime AVP and with Re-Auth-Request-Type set to AUTHORIZE_AUTHENTICATE, and remove the Session-Timeout attribute. 🧚
9.2.1. RADIUS Dynamic Authorization Considerations 🦋
A RADIUS/Diameter gateway that talks to a RADIUS client implementing RADIUS Dynamic Authorization [RADDynAuth] may translate Diameter Re-Auth-Request (RAR) messages and Abort-Session-Request (ASR) messages [BASE] into RADIUS CoA-Request and Disconnect-Request messages, respectively. 🔄
If the RADIUS client doesn't support the capability, the gateway will receive an ICMP Port Unreachable indication when it transmits the RADIUS message. Even if the NAS supports [RADDynAuth], it may not support the Service-Type in the request message. In this case, it will respond with a NAK message and (optionally) an Error-Cause attribute with value 405, "Unsupported Service". If the gateway runs into these error conditions, or if it doesn't support [RADDynAuth], it sends a Diameter Answer message with a Result-Code AVP of "DIAMETER_COMMAND_UNSUPPORTED" to the AAA server. 🙈
When encoding the RADIUS messages, the gateway MUST include the Diameter Session-ID in the RADIUS State attribute value, as mentioned above. The RADIUS client should return it in the response. 🔑
A Diameter Re-Auth-Request (RAR) message [BASE] received by the gateway will be translated into a RADIUS CoA-Request and sent to the RADIUS client. The RADIUS client should respond with a CoA-ACK or CoA-NAK message, which the gateway should translate into a Re-Auth-Answer (RAA) message. 💌
If the gateway receives a RADIUS CoA-NAK response containing a Service-Type Attribute with value "Authorize Only" and an Error-Cause Attribute with value "Request Initiated", this indicates an extended exchange request per [RADDynAuth] section 3.2, note 6. 👀
The response is translated to a Diameter Re-Auth-Answer (RAA) with a Result-Code AVP of "DIAMETER_LIMITED_SUCCESS" and sent to the AAA server. ✅
Afterwards, the gateway should receive a RADIUS Access-Request from the NAS, with a Service-Type of "Authorize Only". This is translated into a Diameter AA-Request with an Auth-Request-Type AVP of AUTHORIZE_ONLY and sent to the AAA server. The AAA server will then reply with a Diameter AA-Answer, which is translated into a RADIUS Access-Accept or Access-Reject, depending on the value of the Result-Code AVP. 🫧
A Diameter Abort-Session-Request (ASR) message [BASE] received by the gateway will be translated into a RADIUS Disconnect-Request and sent to the RADIUS client. The RADIUS client should respond with a Disconnect-ACK or Disconnect-NAK message, which the gateway should translate into an Abort-Session-Answer (ASA) message. 🚪
If the gateway receives a RADIUS Disconnect-NAK response containing a Service-Type Attribute with value "Authorize Only" and an Error-Cause Attribute with value "Request Initiated", the Disconnect-NAK response is translated into a Diameter Abort-Session-Answer (ASA) with a Result-Code AVP of "DIAMETER_LIMITED_SUCCESS" and sent to the AAA server. 🌈
Afterwards, the gateway should receive a RADIUS Access-Request from the NAS, with a Service-Type of "Authorize Only". This is translated into a Diameter AA-Request with an Auth-Request-Type AVP of AUTHORIZE_ONLY and sent to the AAA server. The AAA server will then reply with a Diameter AA-Answer, which is translated into a RADIUS Access-Accept or Access-Reject, depending on the value of the Result-Code AVP. 💜
9.3. AVPs Used Only for Compatibility 🍓
The AVPs defined in this section SHOULD only be used for backwards compatibility when a Diameter/RADIUS translation function is invoked. They are not typically originated by Diameter systems during normal operations. 🧸
+---------------------+
| AVP Flag rules |
|----+-----+----+-----|----+
AVP Section | | |SHLD| MUST| |
Attribute Name Code Defined Value Type |MUST| MAY | NOT| NOT|Encr|
-----------------------------------------|----+-----+----+-----|----|
NAS-Identifier 32 9.3.1 UTF8String | M | P | | V | Y |
NAS-IP-Address 4 9.3.2 OctetString| M | P | | V | Y |
NAS-IPv6-Address 95 9.3.3 OctetString| M | P | | V | Y |
State 24 9.3.4 OctetString| M | P | | V | Y |
Termination- 295 9.3.5 Enumerated | M | P | | V | Y |
Cause | | | | | |
Origin-AAA- 408 9.3.6 Enumerated | M | P | | V | Y |
Protocol | | | | | |
-----------------------------------------|----+-----+----+-----|----|9.3.1. NAS-Identifier AVP 🪪
The NAS-Identifier AVP (AVP Code 32) [RADIUS] is of type UTF8String and contains the identity of the NAS providing service to the user. This AVP SHOULD only be added by a RADIUS/Diameter Translation Agent. When this AVP is present, the Origin-Host AVP identifies the NAS providing service to the user.
In RADIUS, it would be possible for a rogue NAS to forge the NAS-Identifier attribute. Diameter/RADIUS translation agents SHOULD attempt to check a received NAS-Identifier attribute against the source address of the RADIUS packet, by doing an A/AAAA RR query. If the NAS-Identifier attribute contains an FQDN, then such a query would resolve to an IP address matching the source address. However, the NAS-Identifier attribute is not required to contain an FQDN, so such a query could fail. If it fails, an error should be logged, but no action should be taken, other than a reverse lookup on the source address and inserting the resulting FQDN into the Route-Record AVP. 🕵️♀️
Diameter agents and servers SHOULD check whether a NAS-Identifier AVP corresponds to an entry in the Route-Record AVP. If no match is found, then an error is logged, but no other action is taken. 🔍
9.3.2. NAS-IP-Address AVP 🌐
The NAS-IP-Address AVP (AVP Code 4) [RADIUS] is of type OctetString and contains the IP Address of the NAS providing service to the user. This AVP SHOULD only be added by a RADIUS/Diameter Translation Agent. When this AVP is present, the Origin-Host AVP identifies the NAS providing service to the user.
In RADIUS, it would be possible for a rogue NAS to forge the NAS-IP-Address attribute value. Diameter/RADIUS translation agents MUST check a received NAS-IP-Address or NAS-IPv6-Address attribute against the source address of the RADIUS packet. If they do not match and the Diameter/RADIUS translation agent does not know whether the packet was sent by a RADIUS proxy or NAS (e.g., no Proxy-State attribute), then by default it is assumed that the source address corresponds to a RADIUS proxy, and that the NAS Address is behind that proxy, potentially with some additional RADIUS proxies in between. The Diameter/RADIUS translation agent MUST insert entries in the Route-Record AVP corresponding to the apparent route. This implies doing a reverse lookup on the source address and NAS-IP-Address or NAS-IPv6-Address attributes to determine the corresponding FQDNs. 🧭
If the source address and the NAS-IP-Address or NAS-IPv6-Address do not match, and the Diameter/RADIUS translation agent knows that it is talking directly to the NAS (e.g., there are no RADIUS proxies between it and the NAS), then the error should be logged, and the packet MUST be discarded. 🚫
Diameter agents and servers MUST check whether the NAS-IP-Address AVP corresponds to an entry in the Route-Record AVP. This is done by doing a reverse lookup (PTR RR) for the NAS-IP-Address to retrieve the corresponding FQDN, and by checking for a match with the Route-Record AVP. If no match is found, then an error is logged, but no other action is taken. 💅
9.3.3. NAS-IPv6-Address AVP ✨
okay bestie, the NAS-IPv6-Address AVP (AVP Code 95) [RADIUSIPv6] is an OctetString that carries the IPv6 Address of the NAS serving the user 🦋. This AVP SHOULD only be added by a RADIUS/Diameter Translation Agent. When it's present, the Origin-Host AVP is what identifies the NAS providing service to the user 💅.
ngl this one has security drama 💀. In RADIUS, a rogue NAS could forge the NAS-IPv6-Address attribute. So translation agents MUST check a received NAS-IPv6-Address against the source address of the RADIUS packet. If they don't match AND the agent doesn't know whether the packet came from a RADIUS proxy or a NAS (like, there's no Proxy-State attribute), then the default is to assume the source address belongs to a RADIUS proxy, and the NAS-IPv6-Address is sitting behind that proxy, maybe with some more proxies in between 🧚. The translation agent MUST insert entries in the Route-Record AVP that match the apparent route. That means doing a reverse lookup on the source address and the NAS-IPv6-Address to figure out the FQDNs.
If the source address and the NAS-IPv6-Address don't match, and the agent knows it's talking directly to the NAS (no RADIUS proxies in the middle), then the error should be logged and the packet MUST be discarded 🚫.
Diameter agents and servers MUST check whether the NAS-IPv6-Address AVP corresponds to an entry in the Route-Record AVP. You do this with a reverse lookup (PTR RR) on the NAS-IPv6-Address to get the FQDN, then check for a match with the Record-Route AVP. No match? Log an error, but that's it, no other action 🍓.
9.3.4. State AVP
the State AVP (AVP Code 24) [RADIUS] is an OctetString and it has two uses in the Diameter NAS application 🌸.
First, a Diameter Server MAY send the State AVP to a NAS in an AA-Response command that contains a Result-Code of DIAMETER_MULTI_ROUND_AUTH. If it does, the NAS MUST return it unmodified in the subsequent AA-Request command 🔁.
Second, a Diameter Server MAY also send the State AVP to a NAS in an AA-Response command that includes a Termination-Action AVP with the value of AA-REQUEST. If the NAS carries out the Termination-Action by sending a new AA-Request command when the current service ends, it MUST return the State AVP unmodified in that new request command 🎀.
In either usage, the NAS MUST NOT interpret the AVP locally. How you use the State AVP is implementation dependent, so it's up to you 🫶.
9.3.5. Termination-Cause AVP Code Values
this section sets up a mapping between Termination-Cause AVP code values and the RADIUS Acct-Terminate-Cause attribute code values from RFC 2866 [RADIUSAcct] and [RADIUSTypes]. That way a RADIUS/Diameter Translation Agent can convert between the attribute and the AVP values 🔄. It basically extends the definitions in the "Termination-Cause AVP" section of the Base Diameter specification, so it's like a glow-up sequel 💖.
Here's the table that maps Termination-Cause AVP values to RADIUS Acct-Terminate-Cause causes:
+-----------------------+
| Value |
+-----------+-----------+
Cause Value Name | RADIUS | Diameter |
------------------------------|-----------+-----------+
User Request | 1 | 11 |
Lost Carrier | 2 | 12 |
Lost Service | 3 | 13 |
Idle Timeout | 4 | 14 |
Session Timeout | 5 | 15 |
Admin Reset | 6 | 16 |
Admin Reboot | 7 | 17 |
Port Error | 8 | 18 |
NAS Error | 9 | 19 |
NAS Request | 10 | 20 |
NAS Reboot | 11 | 21 |
Port Unneeded | 12 | 22 |
Port Preempted | 13 | 23 |
Port Suspended | 14 | 24 |
Service Unavailable | 15 | 25 |
Callback | 16 | 26 |
User Error | 17 | 27 |
Host Request | 18 | 28 |
Supplicant Restart | 19 | 29 | [RAD802.1X]
Reauthentication Failure | 20 | 30 | [RAD802.1X]
Port Reinit | 21 | 31 | [RAD802.1X]
Port Disabled | 22 | 32 | [RAD802.1X]
------------------------------|-----------+-----------+From RFC 2866, here's what each termination cause means 📖:
User Request User requested termination of service, for
example with LCP Terminate or by logging out.
Lost Carrier DCD was dropped on the port.
Lost Service Service can no longer be provided; for
example, user's connection to a host was
interrupted.
Idle Timeout Idle timer expired.
Session Timeout Maximum session length timer expired.
Admin Reset Administrator reset the port or session.
Admin Reboot Administrator is ending service on the NAS,
for example, prior to rebooting the NAS.
Port Error NAS detected an error on the port that
required ending the session.
NAS Error NAS detected an error (other than on the
port) that required ending the session.
NAS Request NAS ended the session for a non-error reason not
otherwise listed here.
NAS Reboot NAS ended the session to reboot
non-administratively ("crash").
Port Unneeded NAS ended the session because resource usage
fell below a low-water mark (for example, if
a bandwidth-on-demand algorithm decided that
the port was no longer needed).
Port Preempted NAS ended the session to allocate the
port to a higher priority use.
Port Suspended NAS ended the session to suspend a virtual
session.
Service Unavailable NAS was unable to provide requested service.
Callback NAS is terminating the current session
to perform callback for a new session.
User Error Input from user is in error, causing
session termination.
Host Request Login Host terminated session normally.9.3.6. Origin-AAA-Protocol
the Origin-AAA-Protocol AVP (AVP Code 408) is an Enumerated type. It should be inserted in a Diameter message that a gateway system translated from another AAA protocol, like RADIUS 🌉. Its job is to tell the Diameter system receiving the message which source protocol it came from 🕵️♀️.
The supported values are:
1 RADIUS9.4. Prohibited RADIUS Attributes
these RADIUS attributes MUST NOT appear in a Diameter message 🚷. Instead, they get translated to other Diameter AVPs or handled in some special way. The rules for treating these attributes are covered in sections 9.1, 9.2, and 9.6, so go check those out 👑.
Attribute Description Defined Nearest Diameter AVP
-----------------------------------------------------------------
3 CHAP-Password RFC 2865 CHAP-Auth Group
26 Vendor-Specific RFC 2865 Vendor Specific AVP
29 Termination-Action RFC 2865 Authorization-Lifetime
40 Acct-Status-Type RFC 2866 Accounting-Record-Type
42 Acct-Input-Octets RFC 2866 Accounting-Input-Octets
43 Acct-Output-Octets RFC 2866 Accounting-Output-Octets
47 Acct-Input-Packets RFC 2866 Accounting-Input-Packets
48 Acct-Output-Packets RFC 2866 Accounting-Output-Packets
49 Acct-Terminate-Cause RFC 2866 Termination-Cause
52 Acct-Input-Gigawords RFC 2869 Accounting-Input-Octets
53 Acct-Output-Gigawords RFC 2869 Accounting-Output-Octets
80 Message-Authenticator RFC 2869 none - check and discard9.5. Translatable Diameter AVPs
in general, Diameter AVPs that aren't RADIUS compatible have code values greater than 255 🙈. The table in the section above shows which AVPs can be converted into RADIUS attributes.
Another problem may come up with Diameter AVP values that are more than 253 octets long 😬. Some RADIUS attributes (including but not limited to (8)Reply-Message, (79)EAP-Message, and (77)Connect-Info) let you concatenate multiple instances to get around that limit. If concatenation isn't possible, a Result-Code of DIAMETER_INVALID_AVP_LENGTH should be returned 🚨.
9.6. RADIUS Vendor Specific Attributes
RADIUS supports Vendor Specific Attributes (VSAs) through attribute 26 🌈. The recommended format [RADIUS] for the attribute data field is a 4 octet vendor code, followed by a one octet vendor type field and a one octet length field. The last two fields MAY be repeated.
A system talking between Diameter and RADIUS MAY know the specific vendor formats and MAY be able to translate between the two. But lots of RADIUS vendor formats don't follow the example in RFC 2865 [RADIUS]. For instance, some use a longer vendor type code, so the translations in the next two sections won't work in general for those VSAs 😤. RFC 2865 says a robust implementation SHOULD support the field as undistinguished octets.
Systems that don't know the vendor format MAY discard such attributes if they don't have a suitable translation. There's also an alternative format under consideration [VSA] that would preserve the native information and wouldn't need vendor knowledge in the gateway system 👀.
The following sections are an example of translating RADIUS VSAs that use the example RADIUS format, and Diameter VSAs that have type codes less than 255 and value field lengths less than 252 ✨.
9.6.1. Forwarding a Diameter Vendor Specific AVP as a RADIUS VSA
for Type codes less than 255, the value field length MUST be less than 252, or the AVP will be discarded 💔. The RADIUS VSA attribute should consist of the following fields:
RADIUS Type = 26, Vendor Specific Attribute
RADIUS Length = total length of attribute (header + data)
RADIUS Vendor code = Diameter Vendor code
RADIUS Vendor type code = low order byte of Diameter AVP code
RADIUS Vendor data length = length of Diameter dataIf the Diameter AVP code is greater than 255, the RADIUS speaking code may use a Vendor specific field coding, but only if it knows one for that vendor. Otherwise, the AVP will be ignored. If it's flagged as Mandatory, a "DIAMETER_AVP_UNSUPPORTED" Result-Code will be returned, and the RADIUS message won't be sent 🛑.
9.6.2. Forwarding a RADIUS VSA as a Diameter Vendor Specific AVP ✨
okay so when a RADIUS VSA needs to hop over to the Diameter side, it gets wrapped up as a Diameter AVP shaped like this 💅:
Diameter Flags: V=1, M=0, P=0
Diameter Vendor code = RADIUS VSA Vendor code
Diameter AVP code = RADIUS VSA Vendor type code
Diameter AVP length = length of AVP (header + data)
Diameter Data = RADIUS VSA vendor datangl the VSAs are optional by RADIUS rules, and this spec does not set the Mandatory flag 🙈. If an implementor wants a VSA to be mandatory because it represents a required service policy, the RADIUS gateway should have a process to set the bit on the Diameter side 🔥.
If the RADIUS receiving code knows about vendor specific field interpretations for that vendor, it may use them to parse an extended AVP code or data length 🧚. Otherwise, the recommended standard fields will be used 💖.
Nested Multiple vendor data fields MUST be expanded into multiple Diameter AVPs 👑. No skipping this one, bestie 😭.
10. AVP Occurrence Tables 🎀
okay this part is the big tables moment 🦋. The following tables present the AVPs used by NAS applications in NAS messages and specify in which Diameter messages they MAY or MAY NOT be present. [BASE] messages and AVPs are not described in this document. Note that AVPs that can only be present within a Grouped AVP are not represented in this table.
The table uses the following symbols:
0 The AVP MUST NOT be present in the message.
0+ Zero or more instances of the AVP MAY be present in the
message.
0-1 Zero or one instance of the AVP MAY be present in the
message.
1 One instance of the AVP MUST be present in the message.10.1. AA-Request/Answer AVP Table 🌸
The table in this section is limited to the Command Codes defined in this specification.
+-----------+
| Command |
|-----+-----+
Attribute Name | AAR | AAA |
------------------------------|-----+-----+
Acct-Interim-Interval | 0 | 0-1 |
ARAP-Challenge-Response | 0 | 0-1 |
ARAP-Features | 0 | 0-1 |
ARAP-Password | 0-1 | 0 |
ARAP-Security | 0-1 | 0-1 |
ARAP-Security-Data | 0+ | 0+ |
ARAP-Zone-Access | 0 | 0-1 |
Auth-Application-Id | 1 | 1 |
Auth-Grace-Period | 0-1 | 0-1 |
Auth-Request-Type | 1 | 1 |
Auth-Session-State | 0-1 | 0-1 |
Authorization-Lifetime | 0-1 | 0-1 |
------------------------------|-----+-----+ +-----------+
| Command |
|-----+-----+
Attribute Name | AAR | AAA |
------------------------------|-----+-----+
Callback-Id | 0 | 0-1 |
Callback-Number | 0-1 | 0-1 |
Called-Station-Id | 0-1 | 0 |
Calling-Station-Id | 0-1 | 0 |
CHAP-Auth | 0-1 | 0 |
CHAP-Challenge | 0-1 | 0 |
Class | 0 | 0+ |
Configuration-Token | 0 | 0+ |
Connect-Info | 0+ | 0 |
Destination-Host | 0-1 | 0 |
Destination-Realm | 1 | 0 |
Error-Message | 0 | 0-1 |
Error-Reporting-Host | 0 | 0-1 |
Failed-AVP | 0+ | 0+ |
Filter-Id | 0 | 0+ |
Framed-Appletalk-Link | 0 | 0-1 |
Framed-Appletalk-Network | 0 | 0+ |
Framed-Appletalk-Zone | 0 | 0-1 |
Framed-Compression | 0+ | 0+ |
Framed-Interface-Id | 0-1 | 0-1 |
Framed-IP-Address | 0-1 | 0-1 |
Framed-IP-Netmask | 0-1 | 0-1 |
Framed-IPv6-Prefix | 0+ | 0+ |
Framed-IPv6-Pool | 0 | 0-1 |
Framed-IPv6-Route | 0 | 0+ |
Framed-IPX-Network | 0 | 0-1 |
Framed-MTU | 0-1 | 0-1 |
Framed-Pool | 0 | 0-1 |
Framed-Protocol | 0-1 | 0-1 |
Framed-Route | 0 | 0+ |
Framed-Routing | 0 | 0-1 |
Idle-Timeout | 0 | 0-1 |
Login-IP-Host | 0+ | 0+ |
Login-IPv6-Host | 0+ | 0+ |
Login-LAT-Group | 0-1 | 0-1 |
Login-LAT-Node | 0-1 | 0-1 |
Login-LAT-Port | 0-1 | 0-1 |
Login-LAT-Service | 0-1 | 0-1 |
Login-Service | 0 | 0-1 |
Login-TCP-Port | 0 | 0-1 |
Multi-Round-Time-Out | 0 | 0-1 |
------------------------------|-----+-----+ +-----------+
| Command |
|-----+-----+
Attribute Name | AAR | AAA |
------------------------------|-----+-----+
NAS-Filter-Rule | 0 | 0+ |
NAS-Identifier | 0-1 | 0 |
NAS-IP-Address | 0-1 | 0 |
NAS-IPv6-Address | 0-1 | 0 |
NAS-Port | 0-1 | 0 |
NAS-Port-Id | 0-1 | 0 |
NAS-Port-Type | 0-1 | 0 |
Origin-AAA-Protocol | 0-1 | 0-1 |
Origin-Host | 1 | 1 |
Origin-Realm | 1 | 1 |
Origin-State-Id | 0-1 | 0-1 |
Originating-Line-Info | 0-1 | 0 |
Password-Retry | 0 | 0-1 |
Port-Limit | 0-1 | 0-1 |
Prompt | 0 | 0-1 |
Proxy-Info | 0+ | 0+ |
QoS-Filter-Rule | 0 | 0+ |
Re-Auth-Request-Type | 0 | 0-1 |
Redirect-Host | 0 | 0+ |
Redirect-Host-Usage | 0 | 0-1 |
Redirect-Max-Cache-Time | 0 | 0-1 |
Reply-Message | 0 | 0+ |
Result-Code | 0 | 1 |
Route-Record | 0+ | 0+ |
Service-Type | 0-1 | 0-1 |
Session-Id | 1 | 1 |
Session-Timeout | 0 | 0-1 |
State | 0-1 | 0-1 |
Tunneling | 0+ | 0+ |
User-Name | 0-1 | 0-1 |
User-Password | 0-1 | 0 |
------------------------------|-----+-----+10.2. Accounting AVP Tables 💜
the tables in this section show which AVPs defined in this document are to be present and used in NAS application Accounting messages 📊. These AVPs are defined in this document, as well as in [BASE] and [RADIUSAcct].
10.2.1. Accounting Framed Access AVP Table 🦋
this table is used when the Service-Type specifies Framed Access ✨.
+-----------+
| Command |
|-----+-----+
Attribute Name | ACR | ACA |
---------------------------------------|-----+-----+
Accounting-Auth-Method | 0-1 | 0 |
Accounting-Input-Octets | 1 | 0 |
Accounting-Input-Packets | 1 | 0 |
Accounting-Output-Octets | 1 | 0 |
Accounting-Output-Packets | 1 | 0 |
Accounting-Record-Number | 0-1 | 0-1 |
Accounting-Record-Type | 1 | 1 |
Accounting-Realtime-Required | 0-1 | 0-1 |
Accounting-Sub-Session-Id | 0-1 | 0-1 |
Acct-Application-Id | 0-1 | 0-1 |
Acct-Session-Id | 1 | 0-1 |
Acct-Multi-Session-Id | 0-1 | 0-1 |
Acct-Authentic | 1 | 0 |
Acct-Delay-Time | 0-1 | 0 |
Acct-Interim-Interval | 0-1 | 0-1 |
Acct-Link-Count | 0-1 | 0 |
Acct-Session-Time | 1 | 0 |
Acct-Tunnel-Connection | 0-1 | 0 |
Acct-Tunnel-Packets-Lost | 0-1 | 0 |
Authorization-Lifetime | 0-1 | 0 |
Callback-Id | 0-1 | 0 |
Callback-Number | 0-1 | 0 |
Called-Station-Id | 0-1 | 0 |
Calling-Station-Id | 0-1 | 0 |
Class | 0+ | 0+ |
Connection-Info | 0+ | 0 |
Destination-Host | 0-1 | 0 |
Destination-Realm | 1 | 0 |
Event-Timestamp | 0-1 | 0-1 |
Error-Message | 0 | 0-1 |
Error-Reporting-Host | 0 | 0-1 |
Failed-AVP | 0 | 0+ |
---------------------------------------|-----+-----+ +-----------+
| Command |
|-----+-----+
Attribute Name | ACR | ACA |
---------------------------------------|-----+-----+
Framed-AppleTalk-Link | 0-1 | 0 |
Framed-AppleTalk-Network | 0-1 | 0 |
Framed-AppleTalk-Zone | 0-1 | 0 |
Framed-Compression | 0-1 | 0 |
Framed-IP-Address | 0-1 | 0 |
Framed-IP-Netmask | 0-1 | 0 |
Framed-IPv6-Prefix | 0+ | 0 |
Framed-IPv6-Pool | 0-1 | 0 |
Framed-IPX-Network | 0-1 | 0 |
Framed-MTU | 0-1 | 0 |
Framed-Pool | 0-1 | 0 |
Framed-Protocol | 0-1 | 0 |
Framed-Route | 0-1 | 0 |
Framed-Routing | 0-1 | 0 |
NAS-Filter-Rule | 0+ | 0 |
NAS-Identifier | 0-1 | 0-1 |
NAS-IP-Address | 0-1 | 0-1 |
NAS-IPv6-Address | 0-1 | 0-1 |
NAS-Port | 0-1 | 0-1 |
NAS-Port-Id | 0-1 | 0-1 |
NAS-Port-Type | 0-1 | 0-1 |
Origin-AAA-Protocol | 0-1 | 0-1 |
Origin-Host | 1 | 1 |
Origin-Realm | 1 | 1 |
Origin-State-Id | 0-1 | 0-1 |
Originating-Line-Info | 0-1 | 0 |
Proxy-Info | 0+ | 0+ |
QoS-Filter-Rule | 0+ | 0 |
Route-Record | 0+ | 0+ |
Result-Code | 0 | 1 |
Service-Type | 0-1 | 0-1 |
Session-Id | 1 | 1 |
Termination-Cause | 0-1 | 0-1 |
Tunnel-Assignment-Id | 0-1 | 0 |
Tunnel-Client-Endpoint | 0-1 | 0 |
Tunnel-Medium-Type | 0-1 | 0 |
Tunnel-Private-Group-Id | 0-1 | 0 |
Tunnel-Server-Endpoint | 0-1 | 0 |
Tunnel-Type | 0-1 | 0 |
User-Name | 0-1 | 0-1 |
Vendor-Specific-Application-Id | 0-1 | 0-1 |
---------------------------------------|-----+-----+10.2.2. Accounting Non-Framed Access AVP Table ✨
okay so this table is only for when the Service-Type says Non-Framed Access 💅 bestie just check the Service-Type first and you'll know which table to use 🌸
+-----------+
| Command |
|-----+-----+
Attribute Name | ACR | ACA |
---------------------------------------|-----+-----+
Accounting-Auth-Method | 0-1 | 0 |
Accounting-Input-Octets | 1 | 0 |
Accounting-Output-Octets | 1 | 0 |
Accounting-Record-Type | 1 | 1 |
Accounting-Record-Number | 0-1 | 0-1 |
Accounting-Realtime-Required | 0-1 | 0-1 |
Accounting-Sub-Session-Id | 0-1 | 0-1 |
Acct-Application-Id | 0-1 | 0-1 |
Acct-Session-Id | 1 | 0-1 |
Acct-Multi-Session-Id | 0-1 | 0-1 |
Acct-Authentic | 1 | 0 |
Acct-Delay-Time | 0-1 | 0 |
Acct-Interim-Interval | 0-1 | 0-1 |
Acct-Link-Count | 0-1 | 0 |
Acct-Session-Time | 1 | 0 |
Authorization-Lifetime | 0-1 | 0 |
Callback-Id | 0-1 | 0 |
Callback-Number | 0-1 | 0 |
Called-Station-Id | 0-1 | 0 |
Calling-Station-Id | 0-1 | 0 |
Class | 0+ | 0+ |
Connection-Info | 0+ | 0 |
Destination-Host | 0-1 | 0 |
Destination-Realm | 1 | 0 |
Event-Timestamp | 0-1 | 0-1 |
Error-Message | 0 | 0-1 |
Error-Reporting-Host | 0 | 0-1 |
Failed-AVP | 0 | 0+ |
Login-IP-Host | 0+ | 0 |
Login-IPv6-Host | 0+ | 0 |
Login-LAT-Service | 0-1 | 0 |
Login-LAT-Node | 0-1 | 0 |
Login-LAT-Group | 0-1 | 0 |
Login-LAT-Port | 0-1 | 0 |
Login-Service | 0-1 | 0 |
Login-TCP-Port | 0-1 | 0 |
---------------------------------------|-----+-----+
+-----------+
| Command |
|-----+-----+
Attribute Name | ACR | ACA |
---------------------------------------|-----+-----+
NAS-Identifier | 0-1 | 0-1 |
NAS-IP-Address | 0-1 | 0-1 |
NAS-IPv6-Address | 0-1 | 0-1 |
NAS-Port | 0-1 | 0-1 |
NAS-Port-Id | 0-1 | 0-1 |
NAS-Port-Type | 0-1 | 0-1 |
Origin-AAA-Protocol | 0-1 | 0-1 |
Origin-Host | 1 | 1 |
Origin-Realm | 1 | 1 |
Origin-State-Id | 0-1 | 0-1 |
Originating-Line-Info | 0-1 | 0 |
Proxy-Info | 0+ | 0+ |
QoS-Filter-Rule | 0+ | 0 |
Route-Record | 0+ | 0+ |
Result-Code | 0 | 1 |
Session-Id | 1 | 1 |
Service-Type | 0-1 | 0-1 |
Termination-Cause | 0-1 | 0-1 |
User-Name | 0-1 | 0-1 |
Vendor-Specific-Application-Id | 0-1 | 0-1 |
---------------------------------------|-----+-----+11. IANA Considerations ✨
this section is the guidance for IANA 🎀 about registering values for the Diameter protocol, following BCP 26 [IANAConsid] 💖
this doc defines values in the namespaces that were already created in the Diameter Base [BASE] 🦋 the IANA Considerations section of that doc has the assignment rules. Values assigned in this document, or by future IANA action, must be coordinated within this shared namespace 🫶
11.1. Command Codes 🌈
this spec assigns the value 265 from the Command Code namespace defined in [BASE] ✨ see sections 3.1 and 3.2 for how that namespace gets used in this spec 💜
11.2. AVP Codes 🍓
this spec assigns the values 363 - 366 and 400 - 408 from the AVP Code namespace defined in [BASE] 🧚 see sections 4 and 5 for how the namespace works here. Note that the values 363 - 366 are jointly, but consistently, assigned in [DiamMIP] 🌸 this doc also creates one new namespace for IANA to manage, as described in section 11.5 💅
this spec also uses the AVPs in the 0 - 255 range, which are defined in [RADIUSTypes] 🎀 those values are assigned by the policy in RFC 2865 section 6 [RADIUS] and are amended by RFC 3575 [RADIUSIANA] 🔥
11.3. Application Identifier 👑
this spec uses the value one (1) in the Application Identifier namespace as assigned in [BASE] ✨ see section 1.2 above for more info 💖
11.4. CHAP-Algorithm AVP Values 🦋
as defined in section 5.5, the CHAP-Algorithm AVP (AVP Code 403) uses the values of the "PPP AUTHENTICATION ALGORITHMS" namespace defined in [PPPCHAP] 💜
11.5. Accounting-Auth-Method AVP Values 🌷
as defined in section 8.6, the Accounting-Auth-Method AVP (AVP Code 406) defines the values 1 - 5 🫶 all the remaining values are open for assignment via IETF Consensus [IANA] 🌈
11.6. Origin-AAA-Protocol AVP Values 🍓
as defined in section 9.3.6, the Origin-AAA-Protocol AVP (AVP Code 408) defines the value 1 💅 all the remaining values are available for assignment with a "Specification Required" policy [IANAConsid] ✨
12. Security Considerations 🔐
okay this one is SERIOUS bestie 😭 this doc describes how Diameter gets extended for the NAS application. The security considerations of the Diameter protocol itself were already covered in [BASE] 💀 Use of this application of Diameter MUST take into consideration the security issues and requirements of the Base protocol 🚨
this doc doesn't have a security protocol of its own, but it does talk about how PPP authentication protocols can be carried inside Diameter 🎀 the PPP authentication protocols described are PAP and CHAP 🦋
the use of PAP SHOULD be discouraged, because it exposes users' passwords to possibly non-trusted entities 😬 BUT PAP is also used a lot with One-Time Passwords, and those don't expose a security risk 🫠
this is the part that's giving red flag 🚩 CHAP can also be carried within Diameter, and that's required for RADIUS backward compatibility. The CHAP protocol, as used in a RADIUS environment, makes authentication replay attacks easier to pull off 💀
the EAP authentication protocols described in [DiamEAP] can offer better security, as long as you pick a method that fits the situation 🌸💖
13. References 📚
13.1. Normative References 💜
[BASE] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and
J. Arkko, "Diameter Base Protocol", RFC 3588,
September 2003.
[DiamTrans] Aboba, B. and J. Wood, "Authentication, Authorization
and Accounting (AAA) Transport Profile", RFC 3539,
June 2003.
[RADIUS] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, June 2000.
[RADIUSTypes] IANA, "RADIUS Types", URL:
<http://www.iana.org/assignments/radius-types>
[RADIUSIPv6] Aboba, B., Zorn, G., and D. Mitton, "RADIUS and IPv6",
RFC 3162, August 2001.
[IPv6Addr] Nerenberg, L., "IMAP4 Binary Content Extension", RFC
3516, April 2003.
[PPPCHAP] Simpson, W., "PPP Challenge Handshake Authentication
Protocol (CHAP)", RFC 1994, August 1996.
[IANAConsid] Narten, T. and H. Alvestrand, "Guidelines for Writing
an IANA Considerations Section in RFCs", BCP 26, RFC
2434, October 1998.
[IANA] IANA Assigned Numbers Database, URL:
<http://www.iana.org/numbers.html>
[Keywords] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[ANITypes] NANPA Number Resource Info, ANI Assignments, URL:
<http://www.nanpa.com/number_resource_info/
ani_ii_assignments.html>13.2. Informative References 📚
okay so these are the "good to know" references 🧠 you don't need them to get the spec, but they give you the whole backstory. the list is long, so grab a snack 🍓
[RADIUSAcct]Rigney, C., "RADIUS Accounting", RFC 2866, June 2000.[RADIUSExt]Rigney, C., Willats, W., and P. Calhoun, "RADIUS Extensions", RFC 2869, June 2000.[RADTunnels]Zorn, G., Leifer, D., Rubens, A., Shriver, J., Holdrege, M., and I. Goyret, "RADIUS Attributes for Tunnel Protocol Support", RFC 2868, June 2000.[RADTunlAcct]Zorn, G., Aboba, B., and D. Mitton, "RADIUS Accounting Modifications for Tunnel Protocol Support", RFC 2867, June 2000.[RADDynAuth]Chiba, M., Dommety, G., Eklund, M., Mitton, D., and B. Aboba, "Dynamic Authorization Extensions to Remote Authentication Dial In User Service (RADIUS)", RFC 3576, July 2003.[RADIUSIANA]Aboba, B., "IANA Considerations for RADIUS (Remote Authentication Dial In User Service)", RFC 3575, July 2003.[NASModel]Mitton, D. and M. Beadles, "Network Access Server Requirements Next Generation (NASREQNG) NAS Model", RFC 2881, July 2000.[NASCriteria]Beadles, M. and D. Mitton, "Criteria for Evaluating Network Access Server Protocols", RFC 3169, September 2001.[AAACriteria]Aboba, B., Calhoun, P., Glass, S., Hiller, T., McCann, P., Shiino, H., Zorn, G., Dommety, G., Perkins, C., Patil, B., Mitton, D., Manning, S., Beadles, M., Walsh, P., Chen, X., Sivalingham, S., Hameed, A., Munson, M., Jacobs, S., Lim, B., Hirschman, B., Hsu, R., Xu, Y., Campbell, E., Baba, S., and E. Jaques, "Criteria for Evaluating AAA Protocols for Network Access", RFC 2989, November 2000.[DiamEAP]Eronen, P., "Diameter EAP Application", Work in Progress, May 2004.[DiamCMS]Calhoun, P., Bulley, W., and S. Farrell, "Diameter CMS Security Application", Work in Progress, March 2002.[DiamMIP]Calhoun, P., Johansson, T., Perkins, C., Hiller, T., and P. McCann "Diameter Mobile IPv4 Application", RFC 4004, August 2005.[VSA]Mitton, D., "Diameter/RADIUS Vendor Specific AVP Translation", Work in Progress, April 2005.[RAD802.1X]Congdon, P., Aboba, B., Smith, A., Zorn, G., and J. Roese, "IEEE 802.1X Remote Authentication Dial In User Service (RADIUS) Usage Guidelines", RFC 3580, September 2003.[CDMA2000]3GPP2 "P.S0001-B", Wireless IP Network Standard, October 2002.http://www.3gpp2.com/Public_html/specs/P.S0001-B_v1.0.pdf[AppleTalk]Sidhu, Gursharan; Andrews, Richard F. & Oppenheimer, Alan B. "Inside AppleTalk", Second Edition, Apple Computer., 1990[ARAP]Apple Remote Access Protocol (ARAP) Version 2.0 External Reference Specification", Apple Computer, September 1994, R0612LL/B[IPX]Novell, Inc., "NetWare System Technical Interface Overview", June 1989, # 883-000780-001[LAT]Local Area Transport (LAT) Specification V5.0, Digital Equipment Corp., AA-NL26A-TE, June 1989[DIFFSERV]Nichols, K., Blake, S., Baker, F., and D. Black, "Definition of the Differentiated Services Field (DS Field) in the IPv4 and IPv6 Headers", RFC 2474, December 1998.[DIFFSERVAF]Heinanen, J., Baker, F., Weiss, W., and J. Wroclawski, "Assured Forwarding PHB Group", RFC 2597, June 1999.[DIFFSERVEF]Davie, B., Charny, A., Bennet, J.C., Benson, K., Le Boudec, J., Courtney, W., Davari, S., Firoiu, V., and D. Stiliadis, "An Expedited Forwarding PHB (Per-Hop Behavior)", RFC 3246, March 2002.[UTF-8]Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, November 2003.[ISOLatin]ISO 8859. International Standard -- Information Processing -- 8-bit Single-Byte Coded Graphic Character Sets -- Part 1: Latin Alphabet No. 1, ISO 8859-1:1987. URL:<http://www.iso.ch/cate/d16338.html>[PPP]Simpson, W., "The Point-to-Point Protocol (PPP)", STD 51, RFC 1661, July 1994.[PAP]Lloyd, B. and W. Simpson, "PPP Authentication Protocols", RFC 1334, October 1992.[L2TP]Townsley, W., Valencia, A., Rubens, A., Pall, G., Zorn, G., and B. Palter, "Layer Two Tunneling Protocol "L2TP"", RFC 2661, August 1999.[PPPMP]Sklower, K., Lloyd, B., McGregor, G., Carr, D., and T. Coradetti, "The PPP Multilink Protocol (MP)", RFC 1990, August 1996.[PPTP]Hamzeh, K., Pall, G., Verthein, W., Taarud, J., Little, W., and G. Zorn, "Point-to-Point Tunneling Protocol", RFC 2637, July 1999.[IEEE 802.11F]IEEE, "Trial-Use Recommended Practice for Multi-Vendor Access Point Interoperability via an Inter-Access Point Protocol Across Distribution Systems Supporting IEEE 802.11 Operation", IEEE 802.11F-2003, June 2003.
14. Acknowledgements 🫶
the authors wanna give a big shoutout to Carl Rigney, Allan C. Rubens, William Allen Simpson, and Steve Willens for their work on the original RADIUS [RADIUS], which gave us so many of the ideas in this spec 💖 thank you, Carl Rigney, for [RADIUSAcct] and [RADIUSExt] 🎀 and Ward Willats for [RADIUSExt] ✨ Glen Zorn, Bernard Aboba, and Dave Mitton for [RADTunlAcct] and [RADIUSIPv6] 🦋 and Dory Leifer, John Shriver, Matt Holdrege, and Ignacio Goyret for their work on [RADTunnels] 🌸 this document literally stole text and concepts from both [RADTunnels] and [RADIUSExt] 💅 and thanks to Carl Williams for the IPv6-specific text 🧚
the authors also shouted out these people for helping build the Diameter protocol 👑 Bernard Aboba, Jari Arkko, William Bulley, Kuntal Chowdhury, Daniel C. Fox, Lol Grant, Nancy Greene, Jeff Hagg, Peter Heitman, Paul Krumviede, Fergal Ladley, Ryan Moats, Victor Muslin, Kenneth Peirce, Sumit Vakil, John R. Vollbrecht, and Jeff Weisberg 🌈
and finally, Pat Calhoun wants to thank Sun Microsystems, since most of the work on this doc happened while he was working there 💜
Authors' Addresses 🎀
Pat Calhoun
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134
USA
Phone: +1 408-853-5269
EMail: pcalhoun@cisco.com
Glen Zorn
Cisco Systems, Inc.
500 108th Avenue N.E., Suite 500
Bellevue, WA 98004
USA
Phone: 1 425-471-4861
EMail: gwz@cisco.com
David Spence
3259 Bluett Rd.
Ann Arbor, MI 48105
USA
Phone: +1 734 834 6481
EMail: dspence@computer.org
David Mitton
Circular Networks
733 Turnpike St #154
North Andover, MA 01845
EMail: dmitton@circularnetworks.comFull Copyright Statement 📜
Copyright (C) The Internet Society (2005).
This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights.
This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property 🔥
The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org.
Acknowledgement 🌈
Funding for the RFC Editor function is currently provided by the Internet Society. 💖
📦 where this page comes from
- ietf: rfc4005 2005-08
- 💖 girlified by claude-haiku-5-5 on : a language model's rewrite of the original, under its terms