Internet DRAFT - draft-nainar-mpls-rfc8287-errata
draft-nainar-mpls-rfc8287-errata
Network Work group N. Nainar
Internet-Draft C. Pignataro
Updates: 8287 (if approved) F. Iqbal
Intended status: Standards Track Cisco Systems, Inc.
Expires: June 21, 2019 A. Vainshtein
ECI Telecom
December 18, 2018
RFC8287 Sub-TLV Length Clarification
draft-nainar-mpls-rfc8287-errata-01
Abstract
RFC8287 defines the extensions to MPLS LSP Ping and Traceroute for
Segment Routing IGP-Prefix and IGP-Adjacency Segment Identifier
(SIDs) with an MPLS data plane. RFC8287 proposes 3 Target FEC Stack
Sub-TLVs. While the standard defines the format and procedure to
handle those Sub-TLVs, it does not sufficiently clarify how the
length of the Segment ID Sub-TLVs should be computed to include in
the Length field of the Sub-TLVs which may result in interoperability
issues.
This document updates RFC8287 by clarifying the length of each
Segment ID Sub-TLVs defined in RFC8287.
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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This Internet-Draft will expire on June 21, 2019.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Requirements notation . . . . . . . . . . . . . . . . . . . . 3
4. Length 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
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
(SIDs) with an MPLS data plane. [RFC8287] proposes 3 Target FEC
Stack Sub-TLVs. While the standard defines the format and procedure
to handle those Sub-TLVs, it does not sufficiently clarify how the
length of the Segment ID Sub-TLVs should be computed to include in
the Length field of the Sub-TLVs which may result in interoperability
issues.
This document updates [RFC8287] by clarifying the length of each
Segment ID Sub-TLVs defined in [RFC8287].
2. Terminology
This document uses the terminologies defined in
[I-D.ietf-spring-segment-routing], [RFC8029], [RFC8287] and so the
readers are expected to be familiar with the same.
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3. Requirements notation
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 [RFC2119].
4. Length field clarification for Segment ID Sub-TLVs
Section 5 of [RFC8287] defines 3 different Segment ID Sub-TLVs that
will be included in Target FEC Stack TLV defined in [RFC8029]. The
length of each Sub-TLVs MUST be calculated as defined in this
section.
4.1. IPv4 IGP-Prefix Segment ID Sub-TLV
The Sub-TLV length for IPv4 IGP-Prefix Segment ID MUST be set to 8 as
shown in the below TLV format:
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 length for IPv6 IGP-Prefix Segment ID MUST be set to 20
as shown in the below TLV format:
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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 (IPv4 IGP-Prefix SID)| Length = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| |
| IPv6 Prefix |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Prefix Length | Protocol | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
4.3. IGP-Adjacency Segment ID Sub-TLV
The Sub-TLV length for IGP-Adjacency Segment ID varies depending on
the Adjacency Type and Protocol. In any of the allowed combination
of Adjacency Type and Protocol, the sub-TLV length MUST be calculated
by including 2 octets of Reserved field. Below is a table that list
the length for different combinations.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protocol | Length for Adj.Type |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Parallel | IPv4 | IPv6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OSPF | 20 | 20 | 44 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ISIS | 24 | 24 | 48 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Any | 20 | 20 | 44 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
For example, when the Adj. Type is set to Parallel Adjacency and the
Protocol is set to 0, the Sub-TLV will be as below:
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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
This document does not introduce any IANA consideration.
6. Security Considerations
This document updates [RFC8287] and does not introduce any security
considerations.
7. Contributors
The below individuals contributed to this document:
Zafar Ali, Cisco Systems, Inc.
8. Acknowledgement
To be Updated
9. Normative References
[I-D.ietf-spring-segment-routing]
Filsfils, C., Previdi, S., Ginsberg, L., Decraene, B.,
Litkowski, S., and R. Shakir, "Segment Routing
Architecture", draft-ietf-spring-segment-routing-15 (work
in progress), January 2018.
[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>.
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[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>.
[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>.
Authors' Addresses
Nagendra Kumar Nainar
Cisco Systems, Inc.
7200-12 Kit Creek Road
Research Triangle Park, NC 27709
US
Email: naikumar@cisco.com
Carlos Pignataro
Cisco Systems, Inc.
7200-11 Kit Creek Road
Research Triangle Park, NC 27709
US
Email: cpignata@cisco.com
Faisal Iqbal
Cisco Systems, Inc.
2000 Innovation Dr
Ottawa, ON 3E8
Canada
Email: faiqbal@cisco.com
Alexander Vainshtein
ECI Telecom
Israel
Email: vainshtein.alex@gmail.com
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