Network Work group
Internet Engineering Task Force (IETF) N. Nainar
Internet-Draft
Request for Comments: 8690 C. Pignataro
Updates: 8287 (if approved) Cisco Systems, Inc.
Intended status:
Category: Standards Track F. Iqbal
Expires: February 9, 2020
ISSN: 2070-1721 Individual
A. Vainshtein
ECI Telecom
August 8,
December 2019
RFC8287
Clarification of Segment ID Sub-TLV Length Clarification
draft-ietf-mpls-rfc8287-len-clarification-04 for RFC 8287
Abstract
RFC8287
RFC 8287 defines the extensions to MPLS perform LSP Ping and Traceroute
for Segment Routing IGP-Prefix and IGP-Adjacency Segment Identifier Identifiers
(SIDs) with an the MPLS data plane. RFC8287 RFC 8287 proposes 3 three Target FEC
Forwarding Equivalence Class (FEC) Stack
Sub-TLVs. sub-TLVs. While the standard RFC 8287
defines the format and procedure to handle those Sub-TLVs, sub-TLVs, it does
not sufficiently clarify how the length of the Segment ID Sub-TLVs sub-TLVs
should be computed to include be included in the Length field of the Sub-TLVs which may result sub-
TLVs. This ambiguity has resulted in interoperability issues.
This document updates RFC8287 RFC 8287 by clarifying the length of each of
the Segment ID Sub-TLVs sub-TLVs defined in RFC8287. RFC 8287.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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Internet-Drafts are draft documents valid the IETF community. It has
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Internet Standards is available in Section 2 of RFC 7841.
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This Internet-Draft will expire on February 9, 2020.
https://www.rfc-editor.org/info/rfc8690.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 Notation
4. Length field clarification Field Clarification for Segment ID Sub-TLVs . . . . . 3
4.1. IPv4 IGP-Prefix Segment ID Sub-TLV . . . . . . . . . . . 3
4.2. IPv6 IGP-Prefix Segment ID Sub-TLV . . . . . . . . . . . 3
4.3. IGP-Adjacency Segment ID Sub-TLV . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 5
8. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 5
9. Normative References . . . . . . . . . . . . . . . . . . . . 5
Acknowledgements
Contributors
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
[RFC8287] defines the extensions to MPLS LSP Ping and Traceroute for
Segment Routing IGP-Prefix and IGP-Adjacency Segment Identifier Identifiers
(SIDs) with an the MPLS data plane. [RFC8287] proposes 3 three Target FEC
Stack Sub-TLVs. sub-TLVs. While the standard RFC 8287 defines the format and procedure to
handle those Sub-TLVs, sub-TLVs, it does not sufficiently clarify how the
length of the Segment ID Sub-TLVs sub-TLVs should be computed to include be included
in the Length field of the Sub-TLVs sub-TLVs, which may result in
interoperability issues.
This document updates [RFC8287] by clarifying the length of each
Segment ID Sub-TLVs sub-TLVs defined in [RFC8287].
2. Terminology
This document uses the terminologies terminology defined in [RFC8402], [RFC8029],
[RFC8287]
and so the [RFC8287]; readers are expected to be familiar with the
same. terms as
used in those documents.
3. Requirements notation Notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
4. Length field clarification Field Clarification for Segment ID Sub-TLVs
Section 5 of [RFC8287] defines 3 three different Segment ID Sub-TLVs sub-TLVs
that
will can be included in the Target FEC Stack TLV defined in
[RFC8029]. The length of each Sub-TLVs sub-TLV MUST be calculated as defined
in this section.
The TLVs representation TLV representations defined in section Sections 5.1, 5.2 5.2, and 5.3 of
[RFC8287] are updated to clarify the length calculation calculations, as shown in
section
Sections 4.1, 4.2 4.2, and 4.3 4.3, respectively. The updated TLV
representation
representations contain explicitly defined length. lengths.
4.1. IPv4 IGP-Prefix Segment ID Sub-TLV
The Sub-TLV sub-TLV length for the IPv4 IGP-Prefix Segment ID MUST be set to 8
8, as shown in the below TLV format: format below:
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 = 34 (IPv4 IGP-Prefix SID)| Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 prefix |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Prefix Length | Protocol | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.2. IPv6 IGP-Prefix Segment ID Sub-TLV
The Sub-TLV sub-TLV length for the IPv6 IGP-Prefix Segment ID MUST be set to 20
20, as shown in the below TLV format: format below:
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 = 35 (IPv6 IGP-Prefix SID)| Length = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| |
| IPv6 Prefix |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Prefix Length | Protocol | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.3. IGP-Adjacency Segment ID Sub-TLV
The Sub-TLV sub-TLV length for the IGP-Adjacency Segment ID varies depending
on the Adjacency Type and Protocol. In any of the allowed combination
combinations of Adjacency Type and Protocol, the sub-TLV length MUST
be calculated by including 2 octets of the Reserved field. Table 1 below list
lists the length for different combinations of Adj.Type Adj. Type and
Protocol.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+----------+-------------------------------------+
| Protocol | Length for Adj.Type Adj. Type |
|
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +----------+------+------+------------+
| | Parallel | IPv4 | IPv6 | Unnumbered|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Unnumbered |
+==========+==========+======+======+============+
| OSPF | 20 | 20 | 44 | 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+----------+----------+------+------+------------+
| ISIS | 24 | 24 | 48 | 24 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+----------+----------+------+------+------------+
| Any | 20 | 20 | 44 | 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+----------+----------+------+------+------------+
Table 1. 1: IGP-Adjacency SID Length Comparison Computation
For example, when the Adj. Type is set to Parallel Adjacency and the
Protocol is set to 0, the Sub-TLV sub-TLV will be as below:
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 = 36 (IGP-Adjacency SID) | Length = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Adj. Type = 1 | Protocol = 0 | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Interface ID (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Remote Interface ID (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Advertising Node Identifier (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Receiving Node Identifier (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
5. IANA Considerations
IANA has listed this document as an additional reference for the
following entries in the "Sub-TLVs for TLV Types 1, 16, and 21"
registry:
+----------+----------------------------+--------------------------+
| Sub-Type | Sub-TLV Name | Reference |
+==========+============================+==========================+
| 34 | IPv4 IGP-Prefix Segment ID | Section 5.1 of |
| | | [RFC8287], This document does not introduce any IANA consideration. |
+----------+----------------------------+--------------------------+
| 35 | IPv6 IGP-Prefix Segment ID | Section 5.2 of |
| | | [RFC8287], This document |
+----------+----------------------------+--------------------------+
| 36 | IGP-Adjacency Segment ID | Section 5.3 of |
| | | [RFC8287], This document |
+----------+----------------------------+--------------------------+
Table 2: Sub-TLVs for TLV Types 1, 16, and 21 (Updated Entries)
6. Security Considerations
This document updates [RFC8287] and does not introduce any additional
security considerations.
7. Contributors
The below individuals contributed to this document:
Zafar Ali, Cisco Systems, Inc.
8. Acknowledgement
The authors would like to thank Michael Gorokhovsky and Manohar
Doppalapudi for investigating the interop issue during EANTC test.
9. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N.,
Aldrin, S., and M. Chen, "Detecting Multiprotocol Label
Switched (MPLS) Data-Plane Failures", RFC 8029,
DOI 10.17487/RFC8029, March 2017,
<https://www.rfc-editor.org/info/rfc8029>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8287] Kumar, N., Ed., Pignataro, C., Ed., Swallow, G., Akiya,
N., Kini, S., and M. Chen, "Label Switched Path (LSP)
Ping/Traceroute for Segment Routing (SR) IGP-Prefix and
IGP-Adjacency Segment Identifiers (SIDs) with MPLS Data
Planes", RFC 8287, DOI 10.17487/RFC8287, December 2017,
<https://www.rfc-editor.org/info/rfc8287>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>.
Acknowledgements
The authors would like to thank Michael Gorokhovsky and Manohar
Doppalapudi for investigating the interoperability issue during
European Advanced Network Test Center (EANTC) testing.
Contributors
The following individual contributed to this document: Zafar Ali,
Cisco Systems, Inc.
Authors' Addresses
Nagendra Kumar Nainar
Cisco Systems, Inc.
7200-12 Kit Creek Road
Research Triangle Park, NC 27709
US
United States of America
Email: naikumar@cisco.com
Carlos Pignataro
Cisco Systems, Inc.
7200-11 Kit Creek Road
Research Triangle Park, NC 27709
US
United States of America
Email: cpignata@cisco.com
Faisal Iqbal
Individual
Canada
Email: faisal.iqbal@msn.com faisal.ietf@gmail.com
Alexander Vainshtein
ECI Telecom
Israel
Email: vainshtein.alex@gmail.com