RFC 2794

Mobile IP Network Access Identifier Extension for IPv4

📅 published March 2000, from ietf

RFC 2794 🎀 Mobile IP Network Access Identifier Extension for IPv4

Network Working Group 💖 This one is from March 2000, and the category is Standards Track ✨

Authors: P. Calhoun (Sun Microsystems Laboratories) and C. Perkins (Nokia Research Center) 👑

Updates: RFC 2290. It's basically a patch to RFC 2290's Mobile-IPv4 Configuration option for IPCP 🔧 The header doesn't list any RFCs that it obsoletes.

Status of This Memo

This is an Internet standards track protocol for the Internet community, and it's openly asking for discussion and suggestions for improvements 💬 If you want to know where this protocol actually stands in standardization, check the current edition of the "Internet Official Protocol Standards" (STD 1). Distribution of this memo is unlimited 🌸

Copyright Notice

Abstract

Okay so AAA servers already exist across the Internet to handle authentication and authorization for dial-up computers 📞 Mobile nodes using Mobile IP would be just as well served by that, especially when they're trying to connect to foreign domains that have AAA servers 🦋 Those servers identify clients by their Network Access Identifier (NAI) 🪪 This proposal lets the mobile node identify itself by putting its NAI in the Mobile IP Registration Request. It also updates RFC 2290, the Mobile-IPv4 Configuration option for IPCP, so that the Mobile Node's Home Address field is allowed to be zero 🙈

1. Introduction ✨

AAA servers are already part of the Internet for authentication and authorization of dial-up computers, and they'd be super useful for mobile nodes using Mobile IP when those nodes connect to foreign domains with AAA servers 🌈 Right now those servers identify clients using the Network Access Identifier (NAI) [1]. This document specifies the Mobile Node NAI extension to the Mobile IP Registration Request [7] message sent by the mobile node 💅

The NAI is usually what uniquely identifies the mobile node, so the home address doesn't always have to do that job 🧚 That means a mobile node can authenticate itself and get authorized to connect to the foreign domain without even having a home address. A message containing the Mobile Node NAI extension MAY set the Home Address field to zero (0) in the Registration Request, to request that a home address be assigned 🙌

RFC 2290 [8] is where the "Mobile-IPv4 Configuration" option to IPCP is specified, for proper interaction between a mobile node and a peer, which is how the mobile node connects to the network using PPP 🍓 Under that spec, the Mobile Node's Home Address field of the option MUST not be zero. But here, where the mobile node gets identified by its NAI and obtains an address after the PPP phase of connection establishment, the Home Address field is allowed to be zero while everything else in RFC 2290 stays the same. Scenarios from RFC 2290 get interpreted in section 4 💜

The BCP 14 key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" mean what [3] says they mean in this document 📖

2. Mobile Node NAI Extension 🦋

The Mobile Node NAI extension, shown in figure 1, carries the user name in the format defined in [1]. When it's in the Registration Request, the Home Address field MAY be set to zero (0). The Mobile Node NAI extension MUST appear in the Registration Request before both the Mobile-Home Authentication extension and Mobile-Foreign Authentication extension, if present 💖

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Type      |    Length     |           MN-NAI ...
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

             Figure 1: The Mobile Node NAI Extension

Here's how the fields work 👀

Type is 131 (skippable) [7]
Length is the length in bytes of the MN-NAI field
MN-NAI is a string in the NAI format defined in [1]

3. Foreign Agent Considerations 🏠

If Home Address is zero in the Registration Request, the foreign agent MUST use the NAI instead in its pending registration request records, along with the Identification field as usual. If the foreign agent can't manage pending registration request records that way, it MUST return a Registration Reply with Code indicating NONZERO_HOMEADDR_REQD (see section 5) 🙅‍♀️

If the mobile node includes the Mobile Node NAI extension in its Registration Request, then the Registration Reply from the home agent MUST include the Mobile Node NAI extension. If it doesn't, the foreign agent SHOULD send the Registration Reply to the mobile node, changing the Code to the value MISSING_NAI (see section 5) 🚨

The Registration Reply MUST include a nonzero Home Agent address and mobile node's Home Address. If it doesn't, the foreign agent SHOULD send the Registration Reply to the mobile node, changing the Code to the value MISSING_HOME_AGENT or MISSING_HOMEADDR, respectively (see section 5) 🫶

4. Interactions with Mobile-IPv4 Configuration Option to IPCP 🌸

In the Mobile-IPv4 Configuration Option to IPCP [8], the Mobile Node's Home Address field may be zero. This section covers what to do in that case when the mobile node is using the Mobile Node NAI extension in the Mobile IP Registration Request 🧁 Whether or not the IP Address Configuration Option contains a nonzero IP address, the mobile node will later try to get a home address from the Mobile IP Registration Reply ✨

If the IP Address Configuration Option to IPCP has an IP address equal to zero, the PPP peer is expected to allocate and assign a co-located care-of address to the Mobile Node 🌷 If it has a nonzero IP address instead, the PPP peer is expected to assign that address to the Mobile Node as its co-located care-of address 💜

Finally, if the IP Address Configuration Option is left out of the IPCP Configure-Request, then no co-located care-of address is assigned during IPCP 🥹 The mobile node will get a co-located care-of address during a later stage of configuration, or it will use an FA-located care-of address instead 🦋

A. Home Domain Allocation Function (HDAF) 🧚

okay bestie, this appendix introduces a brand new function called the Home Domain Allocation Function (HDAF) 💅 and its whole job is to dynamically assign a Home Address to the mobile node ✨

Figure 2 shows the Home HDAF 🦋. It receives messages from foreign agents (for example, FA) and hands out a Home Address inside the Home Domain. The HDAF does not do any Mobile IP processing on the Registration Request. It just forwards the request to a Home Agent (HA) in the network that can actually handle it 🫶

                                                     +------+
                                                     |      |
                                                 +---+ HA-1 |
        +------+       +------+       +------+   |   |      |
        |      |       |      |       |      |   |   +------+
        |  MN  |-------|  FA  |-------| HDAF +---+     ...
        |      |       |      |       |      |   |   +------+
        +------+       +------+       +------+   |   |      |
                                                 +---+ HA-n |
                                                     |      |
                                                     +------+

            Figure 2: Home Domain Allocator Function (HDAF)

So here's how it goes 🌸 when the mobile node (MN) sends a Registration Request, FA pulls out the NAI and looks up the domain name attached to it. Then FA goes hunting for the HDAF that handles requests for that mobile node's domain. The discovery protocol is outside the scope of this specification 🙈 but as an example, FA might hand off the job of finding an HDAF to a local AAA server. That same local AAA server may also help FA check the mobile node's credentials, using protocols that aren't specified in this document 💜

Addresses 🏠

The working group can be contacted via the current chairs 💖

Basavaraj Patil
Nokia Corporation
6000 Connection Drive
M/S M8-540
Irving, TX 75039
USA

Phone:  +1 972-894-6709
Fax :  +1 972-894-5349
EMail:  Basavaraj.Patil@nokia.com


Phil Roberts
Motorola
1501 West Shure Drive
Arlington Heights, IL 60004
USA

Phone:  +1 847-632-3148
EMail:  QA3445@email.mot.com


Questions about this memo can be directed to:

Charles E. Perkins
Nokia Research Center
313 Fairchild Drive
Mountain View, California 94043
USA

Phone:  +1-650 625-2986
Fax:    +1 650 625-2502
EMail:  charliep@iprg.nokia.com


Pat R. Calhoun
Sun Microsystems Laboratories
15 Network Circle
Menlo Park, California 94025
USA

Phone:  +1 650-786-7733
Fax:    +1 650-786-6445
EMail:  pcalhoun@eng.sun.com

Full Copyright Statement 📜

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Acknowledgement 🫶

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📦 where this page comes from

ietf: rfc2794 2000-03
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