Label Switched Path Stitching with Generalized Multiprotocol Label Switching Traffic Engineering (GMPLS TE)
RFC 5150
Network Working Group A. Ayyangar
Request for Comments: 5150 K. Kompella
Category: Standards Track Juniper Networks
JP. Vasseur
Cisco Systems, Inc.
A. Farrel
Old Dog Consulting
February 2008
Label Switched Path Stitching with
Generalized Multiprotocol Label Switching Traffic Engineering (GMPLS TE)
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.
Abstract
In certain scenarios, there may be a need to combine several
Generalized Multiprotocol Label Switching (GMPLS) Label Switched
Paths (LSPs) such that a single end-to-end (e2e) LSP is realized and
all traffic from one constituent LSP is switched onto the next LSP.
We will refer to this as "LSP stitching", the key requirement being
that a constituent LSP not be allocated to more than one e2e LSP.
The constituent LSPs will be referred to as "LSP segments" (S-LSPs).
This document describes extensions to the existing GMPLS signaling
protocol (Resource Reservation Protocol-Traffic Engineering (RSVP-
TE)) to establish e2e LSPs created from S-LSPs, and describes how the
LSPs can be managed using the GMPLS signaling and routing protocols.
It may be possible to configure a GMPLS node to switch the traffic
from an LSP for which it is the egress, to another LSP for which it
is the ingress, without requiring any signaling or routing extensions
whatsoever and such that the operation is completely transparent to
other nodes. This will also result in LSP stitching in the data
plane. However, this document does not cover this scenario of LSP
stitching.
Ayyangar, et al. Standards Track [Page 1]
RFC 5150 LSP Stitching with GMPLS TE February 2008
Table of Contents
1. Introduction ....................................................2
1.1. Conventions Used in This Document ..........................3
2. Comparison with LSP Hierarchy ...................................3
3. Usage ...........................................................4
3.1. Triggers for LSP Segment Setup .............................4
3.2. Applications ...............................................5
4. Routing Aspects .................................................5
5. Signaling Aspects ...............................................6
5.1. RSVP-TE Signaling Extensions ...............................7
5.1.1. Creating and Preparing an LSP Segment for
Stitching ...........................................7
5.1.1.1. Steps to Support Penultimate Hop
Popping ....................................8
5.1.2. Stitching the e2e LSP to the LSP Segment ............9
5.1.3. RRO Processing for e2e LSPs ........................10
5.1.4. Teardown of LSP Segments ...........................11
5.1.5. Teardown of e2e LSPs ...............................11
5.2. Summary of LSP Stitching Procedures .......................12
5.2.1. Example Topology ...................................12
5.2.2. LSP Segment Setup ..................................12
5.2.3. Setup of an e2e LSP ................................13
5.2.4. Stitching of an e2e LSP into an LSP Segment ........13
6. Security Considerations ........................................14
7. IANA Considerations ............................................15
7.1. Attribute Flags for LSP_ATTRIBUTES Object .................15
7.2. New Error Codes ...........................................15
8. Acknowledgments ................................................16
9. References .....................................................16
9.1. Normative References ......................................16
9.2. Informative References ....................................17
1. Introduction
A stitched Generalized Multiprotocol Label Switching (GMPLS) Traffic
Engineering (TE) Label Switched Path (LSP) is built from a set of
different "LSP segments" (S-LSPs) that are connected together in the
data plane in such a way that a single end-to-end LSP is realized in
the data plane. In this document, we define the concept of LSP
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