Label Switched Path (LSP) Ping/Traceroute for Segment Routing (SR) IGP-Prefix and IGP-Adjacency Segment Identifiers (SIDs) with MPLS Data Planes
RFC 8287
Internet Engineering Task Force (IETF) N. Kumar, Ed.
Request for Comments: 8287 C. Pignataro, Ed.
Category: Standards Track Cisco
ISSN: 2070-1721 G. Swallow
Southend Technical Center
N. Akiya
Big Switch Networks
S. Kini
Individual
M. Chen
Huawei
December 2017
Label Switched Path (LSP) Ping/Traceroute for Segment Routing (SR)
IGP-Prefix and IGP-Adjacency Segment Identifiers (SIDs)
with MPLS Data Planes
Abstract
A Segment Routing (SR) architecture leverages source routing and
tunneling paradigms and can be directly applied to the use of a
Multiprotocol Label Switching (MPLS) data plane. A node steers a
packet through a controlled set of instructions called "segments" by
prepending the packet with an SR header.
The segment assignment and forwarding semantic nature of SR raises
additional considerations for connectivity verification and fault
isolation for a Label Switched Path (LSP) within an SR architecture.
This document illustrates the problem and defines extensions to
perform LSP Ping and Traceroute for Segment Routing IGP-Prefix and
IGP-Adjacency Segment Identifiers (SIDs) with an MPLS data plane.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8287.
Kumar, et al. Standards Track [Page 1]
RFC 8287 LSP Ping/Trace for SR-MPLS December 2017
Copyright Notice
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Kumar, et al. Standards Track [Page 2]
RFC 8287 LSP Ping/Trace for SR-MPLS December 2017
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Coexistence of SR-Capable and Non-SR-Capable Node
Scenarios . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 5
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Challenges with Existing Mechanisms . . . . . . . . . . . . . 5
4.1. Path Validation in Segment Routing Networks . . . . . . . 5
5. Segment ID Sub-TLV . . . . . . . . . . . . . . . . . . . . . 7
5.1. IPv4 IGP-Prefix Segment ID . . . . . . . . . . . . . . . 7
5.2. IPv6 IGP-Prefix Segment ID . . . . . . . . . . . . . . . 8
5.3. IGP-Adjacency Segment ID . . . . . . . . . . . . . . . . 9
6. Extension to Downstream Detailed Mapping TLV . . . . . . . . 11
7. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.1. FECs in Target FEC Stack TLV . . . . . . . . . . . . . . 11
7.2. FEC Stack Change Sub-TLV . . . . . . . . . . . . . . . . 12
7.3. Segment ID POP Operation . . . . . . . . . . . . . . . . 13
7.4. Segment ID Check . . . . . . . . . . . . . . . . . . . . 13
7.5. TTL Consideration for Traceroute . . . . . . . . . . . . 19
8. Backward Compatibility with Non-SR Devices . . . . . . . . . 19
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
9.1. New Target FEC Stack Sub-TLVs . . . . . . . . . . . . . . 20
9.2. Protocol in the Segment ID Sub-TLV . . . . . . . . . . . 20
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