RFC 6829
Label Switched Path (LSP) Ping for Pseudowire Forwarding Equivalence Classes (FECs) Advertised over IPv6
RFC 6829 💖 Label Switched Path (LSP) Ping for Pseudowire Forwarding Equivalence Classes (FECs) Advertised over IPv6
okay bestie, let's get into it 🎀 this one is from the IETF and dated January 2013 📅
it's a Standards Track doc (so it's a real spec, not just vibes 💅) and it updates RFC 4379 🔥. the header doesn't list anything it obsoletes. the authors are M. Chen (Huawei Technologies Co., Ltd), P. Pan (Infinera), C. Pignataro, and R. Asati (Cisco) 🫶. the ISSN is 2070-1721 ✨
Abstract
okay so MPLS LSP Ping and traceroute are the go-to tools for catching data-plane failures in all MPLS LSPs 🧚, including the LSPs used in each direction of an MPLS Pseudowire (PW) 🦋. the catch is that the PW-specific LSP Ping and traceroute elements aren't specified for IPv6 address usage 😭
this doc extends the PW LSP Ping and traceroute so they work with PWs that get set up and maintained using IPv6 LDP sessions 💜 it also updates RFC 4379 ✨
Status of This Memo
this is an Internet Standards Track document 💅
it's a product of the Internet Engineering Task Force (IETF) and represents the consensus of the IETF community 🫶. it got public review and was approved for publication by the Internet Engineering Steering Group (IESG) 👑. more info on Internet Standards is in Section 2 of RFC 5741 🌈
for the current status, any errata, and how to give feedback, check http://www.rfc-editor.org/info/rfc6829 🎀
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved. 🌸
this doc is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) as in effect on the date of publication 📜. please review these carefully because they describe your rights and restrictions for this doc 🙈. code components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions, and they're provided without warranty as described in the Simplified BSD License 💀
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Pseudowire IPv4 Target FEC Stack Sub-TLVs . . . . . . . . . . . 3
3. Pseudowire IPv6 Target FEC Stack Sub-TLVs . . . . . . . . . . . 4
3.1. FEC 128 Pseudowire . . . . . . . . . . . . . . . . . . . . 4
3.2. FEC 129 Pseudowire . . . . . . . . . . . . . . . . . . . . 5
4. Summary of Changes . . . . . . . . . . . . . . . . . . . . . . 6
5. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
9.1. Normative References . . . . . . . . . . . . . . . . . . . 7
9.2. Informative References . . . . . . . . . . . . . . . . . . 71. Introduction ✨
okay so MPLS LSP Ping and traceroute are defined in [RFC4379] 🧚. these can detect data-plane failures in all MPLS LSPs, including Pseudowires (PWs) 💖. the problem is the PW LSP Ping and traceroute elements aren't specified for IPv6 address usage 😭
here's the deal: the PW Forwarding Equivalence Class (FEC) sub-TLVs for the Target FEC Stack in LSP Ping and traceroute are only defined for IPv4 Provider Edge (PE) routers 🙈. they don't work when PEs use IPv6 addresses. there are three PW-related Target FEC sub-TLVs right now (FEC 128 Pseudowire-Deprecated, FEC 128 Pseudowire-Current, and FEC 129 Pseudowire; see Sections 3.2.8 through 3.2.10 of [RFC4379]) 🦋. these carry the source and destination addresses of the LDP session, and only an IPv4 LDP session is covered right now 🥺
even though the PE IP address family isn't explicit in the sub-TLV definition, you can infer it by checking the lengths of the Sender's/Remote PE Address fields or by calculating the length of the sub-TLVs (see Section 3.2 of [RFC4379]) 🤓. but when an IPv6 LDP session is used, these existing sub-TLVs can't be used because the addresses won't fit 💀. also, every other sub-TLV comes in pairs (one for IPv4, one for IPv6), but the PW sub-TLVs don't 🙃
this doc updates [RFC4379] to explicitly constrain the existing PW FEC sub-TLVs for IPv4 LDP sessions 🎀. it also extends PW LSP Ping to IPv6 LDP sessions, meaning when IPv6 LDP sessions signal the PW, the Sender's and Receiver's IP addresses are IPv6 addresses 🌈. to do that, it renames the existing PW sub-TLVs to say "IPv4" and defines two new Target FEC sub-TLVs (FEC 128 Pseudowire IPv6 sub-TLV and FEC 129 Pseudowire IPv6 sub-TLV) 👑. that extends PW LSP Ping and traceroute to IPv6 when an IPv6 LDP session [MPLS-LDP] signals the Pseudowire 🫶. also, FEC 128 Pseudowire (Deprecated) isn't defined for IPv6 in this doc 🙈
the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. 🔥
2. Pseudowire IPv4 Target FEC Stack Sub-TLVs 🌸
this doc updates Section 3.2 and Sections 3.2.8 through 3.2.10 of [RFC4379] as described here and as indicated in Sections 4 and 6 💖. it's done to avoid any potential ambiguity and confusion, and to make it clear these TLVs carry only IPv4 addresses 💅. the changes are only to the names of fields. there are no semantic changes ✨
Sections 3.2.8 through 3.2.10 of [RFC4379] list the PW sub-TLVs and say:
"FEC 128" Pseudowire (Deprecated)
"FEC 128" Pseudowire
"FEC 129" Pseudowirethese names and titles are now changed to:
"FEC 128" Pseudowire - IPv4 (Deprecated)
"FEC 128" Pseudowire - IPv4
"FEC 129" Pseudowire - IPv4also, when referring to PE addresses, Sections 3.2.8 through 3.2.10 of [RFC4379] say:
Sender's PE Address
Remote PE Addressand these are now updated to say:
Sender's PE IPv4 Address
Remote PE IPv4 Address3. Pseudowire IPv6 Target FEC Stack Sub-TLVs 🧚
3.1. FEC 128 Pseudowire 🦋
the FEC 128 Pseudowire IPv6 sub-TLV has a structure consistent with the FEC 128 Pseudowire sub-TLV from Section 3.2.9 of [RFC4379] 🫶. here's the encoding:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FEC 128 PW IPv6 Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Sender's PE IPv6 Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Remote PE IPv6 Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PW ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PW Type | Must Be Zero |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: FEC 128 Pseudowire - IPv6here's what each field means 🍓
- FEC 128 PW IPv6 Type:
24. 2 octets. - Length: defines the length in octets of the value field of the sub-TLV, and its value is
38. 2 octets. - Sender's PE IPv6 Address: the source IP address of the target IPv6 LDP session. 16 octets.
- Remote PE IPv6 Address: the destination IP address of the target IPv6 LDP session. 16 octets.
- PW ID: same as FEC 128 Pseudowire IPv4 [RFC4379].
- PW Type: same as FEC 128 Pseudowire IPv4 [RFC4379].
3.2. FEC 129 Pseudowire 👑
the FEC 129 Pseudowire IPv6 sub-TLV has a structure consistent with the FEC 129 Pseudowire sub-TLV from Section 3.2.10 of [RFC4379] 💜. here's the encoding for FEC 129 Pseudowire IPv6:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FEC 129 PW IPv6 Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Sender's PE IPv6 Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Remote PE IPv6 Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PW Type | AGI Type | AGI Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ AGI Value ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII Type | SAII Length | SAII Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ SAII Value (continued) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| AII Type | TAII Length | TAII Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ TAII Value (continued) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TAII (cont.) | 0-3 octets of zero padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: FEC 129 Pseudowire - IPv6here's the breakdown 🌈
- FEC 129 PW IPv6 Type:
25. 2 octets. - Length: defines the length in octets of the value field of the sub-TLV. 2 octets
the length of this TLV is 40 + AGI (Attachment Group Identifier) length + SAII (Source Attachment Individual Identifier) length + TAII (Target Attachment Individual Identifier) length. padding is used to make the total length a multiple of 4, and the length of the padding is not included in the Length field 🧮
- Sender's PE IPv6 Address: the source IP address of the target IPv6 LDP session. 16 octets.
- Remote PE IPv6 Address: the destination IP address of the target IPv6 LDP session. 16 octets.
the other fields are the same as FEC 129 Pseudowire IPv4 [RFC4379] ✨
4. Summary of Changes 💅
Section 3.2 of [RFC4379] tabulates all the sub-TLVs for the Target FEC Stack 📋. with the changes from Sections 2 and 3, the table would look like this:
Sub-Type Length Value Field
-------- ------ -----------
...
9 10 "FEC 128" Pseudowire - IPv4 (Deprecated)
10 14 "FEC 128" Pseudowire - IPv4
11 16+ "FEC 129" Pseudowire - IPv4
...
24 38 "FEC 128" Pseudowire - IPv6
25 40+ "FEC 129" Pseudowire - IPv65. Operation ✨
okay so this section is short and sweet bestie 🎀 this document does not define any new procedures 💅 like, zero new vibes. the process described in [RFC4379] MUST be used. no cap, that one's a must 🫶
6. IANA Considerations 🌸
okay so IANA is the registry queen 👑 and they made some assignments in the "Multi-Protocol Label Switching (MPLS) Label Switched Paths (LSPs) Ping Parameters" registry 🦋
the "TLVs and sub-TLVs" sub-registry gets some glow-ups for the TLV Type 1 "Target FEC Stack" 💖 there are three updates and two additions total ✨
the three Sub-TLVs got their Value field names updated to include the "IPv4" qualifier (see Section 2) 💅 and their Reference now points to this document 🧚
Type Sub-Type Value Field
---- -------- -----------
1 9 "FEC 128" Pseudowire - IPv4 (Deprecated)
1 10 "FEC 128" Pseudowire - IPv4
1 11 "FEC 129" Pseudowire - IPv4then there are two brand new entries for the Sub-Type field of the Target FEC TLV (see Section 3) 🍓 literally new girlies on the block 🌈
Type Sub-Type Value Field
---- -------- -----------
1 24 "FEC 128" Pseudowire - IPv6
1 25 "FEC 129" Pseudowire - IPv67. Security Considerations 💀
okay this one is serious bestie 😭 this document does not introduce any new security issues 🫶 the security mechanisms defined in [RFC4379] apply here, so go check those out too 🔒
8. Acknowledgements 🫶
the authors gratefully acknowledge the review and comments of Vanson Lim, Tom Petch, Spike Curtis, Loa Andersson, and Kireeti Kompella 💜 thank you queens ✨
9. References 📚
9.1. Normative References 💖
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4379] Kompella, K. and G. Swallow, "Detecting Multi-Protocol
Label Switched (MPLS) Data Plane Failures", RFC 4379,
February 2006.9.2. Informative References 🦋
[MPLS-LDP] Asati, R., Manral, V., Papneja, R., and C. Pignataro,
"Updates to LDP for IPv6", Work in Progress, June 2012.Authors' Addresses 🌟
Mach(Guoyi) Chen
Huawei Technologies Co., Ltd
No. 3 Xinxi Road, Shang-di, Hai-dian District
Beijing 100085
China
EMail: mach@huawei.com
Ping Pan
Infinera
US
EMail: ppan@infinera.com
Carlos Pignataro
Cisco Systems
7200-12 Kit Creek Road
Research Triangle Park, NC 27709
US
EMail: cpignata@cisco.com
Rajiv Asati
Cisco Systems
7025-6 Kit Creek Road
Research Triangle Park, NC 27709
US
EMail: rajiva@cisco.comthat's the whole thing, bestie!! 🎀💅✨
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