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Multiprotocol Label Switching Architecture (RFC3031)

IP.com Disclosure Number: IPCOM000005223D
Original Publication Date: 2001-Jan-01
Included in the Prior Art Database: 2001-Aug-17

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

E. Rosen: AUTHOR [+3]

Abstract

This document specifies the architecture for Multiprotocol Label Switching (MPLS).

This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 2% of the total text.

Network Working Group E. Rosen Request for Comments: 3031 Cisco Systems, Inc. Category: Standards Track A. Viswanathan Force10 Networks, Inc.

R. Callon Juniper Networks, Inc.

January 2001

Multiprotocol Label Switching Architecture

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 architecture for Multiprotocol Label Switching (MPLS).

Table of Contents

1 Specification ...................................... 3 2 Introduction to MPLS ............................... 3 2.1 Overview ........................................... 4 2.2 Terminology ........................................ 6 2.3 Acronyms and Abbreviations ......................... 9 2.4 Acknowledgments .................................... 9 3 MPLS Basics ........................................ 9 3.1 Labels ............................................. 9 3.2 Upstream and Downstream LSRs ....................... 10 3.3 Labeled Packet ..................................... 11 3.4 Label Assignment and Distribution .................. 11 3.5 Attributes of a Label Binding ...................... 11 3.6 Label Distribution Protocols ....................... 11 3.7 Unsolicited Downstream vs. Downstream-on-Demand .... 12 3.8 Label Retention Mode ............................... 12 3.9 The Label Stack .................................... 13 3.10 The Next Hop Label Forwarding Entry (NHLFE) ........ 13 3.11 Incoming Label Map (ILM) ........................... 14

Rosen, et al. Standards Track [Page 1]

RFC 3031 MPLS Architecture January 2001

3.12 FEC-to-NHLFE Map (FTN) ............................. 14 3.13 Label Swapping ..................................... 15 3.14 Scope and Uniqueness of Labels ..................... 15 3.15 Label Switched Path (LSP), LSP Ingress, LSP Egress . 16 3.16 Penultimate Hop Popping ............................ 18 3.17 LSP Next Hop ....................................... 20 3.18 Invalid Incoming Labels ............................ 20 3.19 LSP Control: Ordered versus Independent ............ 20 3.20 Aggregation ........................................ 21 3.21 Route Selection .................................... 23 3.22 Lack of Outgoing Label ............................. 24 3.23 Time-to-Live (TTL) ................................. 24 3.24 Loop Control ....................................... 25 3.25 Label Encodings .................................... 26 3.25.1 MPLS-specific Hardware and/or Software ............. 26 3.25.2 ATM Switches as LSRs .........