Definition of a Record Route Object (RRO) Node-Id Sub-Object
RFC 4561
Document | Type | RFC - Proposed Standard (June 2006; No errata) | |
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Authors | Vasseur Jp , Zafar Ali , Siva Sivabalan | ||
Last updated | 2015-10-14 | ||
Stream | Internet Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Stream | WG state | WG Document | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 4561 (Proposed Standard) | |
Action Holders |
(None)
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Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Alex Zinin | ||
Send notices to | (None) |
Network Working Group J.-P. Vasseur, Ed. Request for Comments: 4561 Z. Ali Category: Standards Track S. Sivabalan Cisco Systems, Inc. June 2006 Definition of a Record Route Object (RRO) Node-Id Sub-Object Status of This Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2006). Abstract In the context of MPLS TE Fast Reroute, the Merge Point (MP) address is required at the Point of Local Repair (PLR) in order to select a backup tunnel intersecting a fast reroutable Traffic Engineering Label Switched Path (TE LSP) on a downstream Label Switching Router (LSR). However, existing protocol mechanisms are not sufficient to find an MP address in multi-domain routing networks where a domain is defined as an Interior Gateway Protocol (IGP) area or an Autonomous System (AS). Hence, the current MPLS Fast Reroute mechanism cannot be used in order to protect inter-domain TE LSPs from a failure of an Area Border Router (ABR) or Autonomous System Border Router (ASBR). This document specifies the use of existing Record Route Object (RRO) IPv4 and IPv6 sub-objects (with a new flag defined) thus defining the node-id sub-object in order to solve this issue. The MPLS Fast Reroute mechanism mentioned in this document refers to the "Facility backup" MPLS TE Fast Reroute method. Vasseur, et al. Standards Track [Page 1] RFC 4561 Definition of RRO Node-Id Sub-Object June 2006 Table of Contents 1. Introduction ....................................................2 2. Terminology .....................................................4 2.1. Conventions Used in This Document ..........................5 3. Signaling Node-Ids in RROs ......................................5 4. Finding Merge Point .............................................6 5. Security Considerations .........................................7 6. Acknowledgements ................................................7 7. References ......................................................7 7.1. Normative References .......................................7 7.2. Informative References .....................................8 1. Introduction MPLS Fast Reroute (FRR) [FAST-REROUTE] is a fast recovery local protection technique used to protect Traffic Engineering LSPs from link/node/Shared Risk Link Group (SRLG) failure. One or more backup tunnels are pre-established to protect against the failure of a link/node/SRLG. In case of failure, every protected TE LSP traversing the failed resource is rerouted onto the appropriate backup tunnel. There are several requirements on the backup tunnel path that must be satisfied. First, the backup tunnel must not traverse the element that it protects. In addition, a primary tunnel and its associated backup tunnel should intersect at least at two points (nodes): Point of Local Repair (PLR) and Merge Point (MP). The former is the head- end LSR of the backup tunnel, and the latter is the tail-end LSR of the backup tunnel. The PLR is where FRR is triggered when link/node/SRLG failure happens. There are different methods for computing paths for backup tunnels at a given PLR. Specifically, a user can statically configure one or more backup tunnels at the PLR with an explicitly configured path, or the PLR can be configured to automatically compute a backup path or to send a path computation request to a PCE (see [PCE-ARCH]). Consider the following scenario (Figure 1). Assumptions: - A multi-area network made of three areas: 0, 1, and 2. - A fast reroutable TE LSP T1 (TE LSP signaled with the "Local Protection Desired" bit set in the SESSION-ATTRIBUTE object or the FAST-REROUTE object) from R0 to R3. Vasseur, et al. Standards Track [Page 2] RFC 4561 Definition of RRO Node-Id Sub-Object June 2006 - A backup tunnel B1 from R1 to R2, not traversing ABR1, and following the R1-ABR3-R2 path. - The PLR R1 reroutes any protected TE LSP traversing ABR1 onto the backup tunnel B1 in case of ABR1's failure. <--- area 1 --><---area 0---><---area 2---> R0-----R1-ABR1--R2------ABR2--------R3 \ / \ /Show full document text