Encoding of Attributes for Multiprotocol Label Switching (MPLS) Label Switched Path (LSP) Establishment Using Resource ReserVation Protocol-Traffic Engineering (RSVP-TE)
RFC 4420

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Network Working Group                                     A. Farrel, Ed.
Request for Comments: 4420                            Old Dog Consulting
Updates: 3209, 3473                                     D. Papadimitriou
Category: Standards Track                                        Alcatel
                                                           J.-P. Vasseur
                                                     Cisco Systems, Inc.
                                                             A. Ayyangar
                                                        Juniper Networks
                                                           February 2006

    Encoding of Attributes for Multiprotocol Label Switching (MPLS)
             Label Switched Path (LSP) Establishment Using
      Resource ReserVation Protocol-Traffic Engineering (RSVP-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.

Copyright Notice

   Copyright (C) The Internet Society (2006).

Abstract

   Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs) may
   be established using the Resource Reservation Protocol Traffic
   Engineering (RSVP-TE) extensions.  This protocol includes an object
   (the SESSION_ATTRIBUTE object) that carries a Flags field used to
   indicate options and attributes of the LSP.  That Flags field has
   eight bits allowing for eight options to be set.  Recent proposals in
   many documents that extend RSVP-TE have suggested uses for each of
   the previously unused bits.

   This document defines a new object for RSVP-TE messages that allows
   the signaling of further attribute bits and also the carriage of
   arbitrary attribute parameters to make RSVP-TE easily extensible to
   support new requirements.  Additionally, this document defines a way
   to record the attributes applied to the LSP on a hop-by-hop basis.

   The object mechanisms defined in this document are equally applicable
   to Generalized MPLS (GMPLS) Packet Switch Capable (PSC) LSPs and to
   GMPLS non-PSC LSPs.

Farrel, et al.            Standards Track                       [Page 1]
RFC 4420        Attributes for MPLS LSPs Using RSVP-TE     February 2006

Table of Contents

   1. Introduction and Problem Statement ..............................3
      1.1. Applicability to Generalized MPLS ..........................4
      1.2. A Rejected Alternate Solution ..............................4
   2. Terminology .....................................................5
   3. Attributes TLVs .................................................5
      3.1. Attributes Flags TLV .......................................6
   4. LSP_ATTRIBUTES Object ...........................................6
      4.1. Format .....................................................7
      4.2. Generic Processing Rules for Path Messages .................7
      4.3. Generic Processing Rules for Resv Messages .................8
   5. LSP_REQUIRED_ATTRIBUTES Object ..................................9
      5.1. Format .....................................................9
      5.2. Generic Processing Rules ...................................9
   6. Inheritance Rules ..............................................10
   7. Recording Attributes Per LSP ...................................11
      7.1. Requirements ..............................................11
      7.2. RRO Attributes Subobject ..................................11
      7.3. Procedures ................................................12
           7.3.1. Subobject Presence Rules ...........................12
           7.3.2. Reporting Compliance with LSP Attributes ...........12
           7.3.3. Reporting Per-Hop Attributes .......................13
           7.3.4. Default Behavior ...................................13
   8. Summary of Attribute Bit Allocation ............................13
   9. Message Formats ................................................14
   10. Guidance for Key Application Scenarios ........................14
      10.1. Communicating to Egress LSRs .............................15
      10.2. Communicating to Key Transit LSRs ........................15
      10.3. Communicating to All LSRs ................................16
   11. IANA Considerations ...........................................16
      11.1. New RSVP C-Nums and C-Types ..............................16
      11.2. New TLV Space ............................................17
      11.3. Attributes Flags .........................................17
      11.4. New Error Codes ..........................................18
      11.5. New Record Route Subobject Identifier ....................18