Carrying Label Information in BGP-4 (RFC3107)
Original Publication Date: 2001-May-01
Included in the Prior Art Database: 2001-Aug-21
Publishing Venue
Internet Society Requests For Comment (RFCs)
Related People
Y. Rekhter: AUTHOR [+1]
Abstract
This document specifies the way in which the label mapping information for a particular route is piggybacked in the same Border Gateway Protocol (BGP) Update message that is used to distribute the route itself. When BGP is used to distribute a particular route, it can be also be used to distribute a Multiprotocol Label Switching (MPLS) label which is mapped to that route.
Network Working Group Y. Rekhter Request for Comments: 3107 Juniper Networks Category: Standards Track E. Rosen Cisco Systems, Inc.
May 2001
Carrying Label Information in BGP-4
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 (2001). All Rights Reserved.
Abstract
This document specifies the way in which the label mapping information for a particular route is piggybacked in the same Border Gateway Protocol (BGP) Update message that is used to distribute the route itself. When BGP is used to distribute a particular route, it can be also be used to distribute a Multiprotocol Label Switching (MPLS) label which is mapped to that route.
Table of Contents
1 Specification of Requirements .......................... 2 2 Overview ............................................... 2 3 Carrying Label Mapping Information ..................... 3 4 Advertising Multiple Routes to a Destination ........... 4 5 Capability Advertisement ............................... 4 6 When the BGP Peers are not Directly Adjacent ........... 5 7 Security Considerations ................................ 5 8 Acknowledgments ........................................ 6
9 References ............................................. 6 10 Authors' Addresses ..................................... 7 11 Full Copyright Statement ............................... 8
Rekhter Rosen Standards Track [Page 1]
RFC 3107 Carrying Label Information in BGP-4 May 2001
1. Specification of Requirements
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 RFC 2119.
2. Overview
When BGP is used to distribute a particular route, it can also be used to distribute an MPLS label that is mapped to that route [MPLS- ARCH]. This document specifies the way in which this is done. The label mapping information for a particular route is piggybacked in the same BGP Update message that is used to distribute the route itself.
This can be useful in the following situations:
If two immediately adjacent Label Switched Routers (LSRs) are also BGP peers, then label distribution can be done without the need for any other label distribution protocol.
Suppose one's network consists of two "classes" of LSR: exterior LSRs, which interface to other networks, and interior LSRs, which serve only to carry traffic between exterior LSRs. Suppose that the exterior LSRs are BGP speakers. If the BGP speakers distr...