RFC 3785 (rfc3785) - Page 1 of 8
Use of Interior Gateway Protocol (IGP) Metric as a second MPLS Traffic Engineering (TE) Metric
Alternative Format: Original Text Document
Network Working Group F. Le Faucheur
Request for Comments: 3785 R. Uppili
BCP: 87 Cisco Systems, Inc.
Category: Best Current Practice A. Vedrenne
P. Merckx
Equant
T. Telkamp
Global Crossing
May 2004
Use of Interior Gateway Protocol (IGP) Metric
as a second MPLS Traffic Engineering (TE) Metric
Status of this Memo
This document specifies an Internet Best Current Practices for the
Internet Community, and requests discussion and suggestions for
improvements. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract
This document describes a common practice on how the existing metric
of Interior Gateway Protocols (IGP) can be used as an alternative
metric to the Traffic Engineering (TE) metric for Constraint Based
Routing of MultiProtocol Label Switching (MPLS) Traffic Engineering
tunnels. This effectively results in the ability to perform
Constraint Based Routing with optimization of one metric (e.g., link
bandwidth) for some Traffic Engineering tunnels (e.g., Data Trunks)
while optimizing another metric (e.g., propagation delay) for some
other tunnels with different requirements (e.g., Voice Trunks). No
protocol extensions or modifications are required. This text
documents current router implementations and deployment practices.
1. Introduction
Interior Gateway Protocol (IGP) routing protocols (OSPF and IS-IS) as
well as MultiProtocol Label Switching (MPLS) signaling protocols
(RSVP-TE and CR-LDP) have been extended (as specified in [ISIS-TE],
[OSPF-TE], [RSVP-TE] and [CR-LDP]) in order to support the Traffic
Engineering (TE) functionality as defined in [TE-REQ].
Le Faucheur, et al. Best Current Practice