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LDP State Machine (RFC3215)

IP.com Disclosure Number: IPCOM000006864D
Original Publication Date: 2002-Jan-01
Included in the Prior Art Database: 2002-Feb-07

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

C. Boscher: AUTHOR [+4]

Abstract

This document provides state machine tables for ATM (Asynchronous Transfer Mode) switch LSRs. In the current LDP specification, there is no state machine specified for processing LDP messages. We think that defining a common state machine is very important for interoperability between different LDP and CR-LDP implementations.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 3% of the total text.

Network Working Group                                         C. Boscher

Request for Comments: 3215                                     P. Cheval

Category: Informational                                          Alcatel

                                                                   L. Wu

                                                                   Cisco

                                                                 E. Gray

                                                               Sandburst

                                                            January 2002

                           LDP State Machine

Status of this Memo

   This memo provides information for the Internet community.  It does

   not specify an Internet standard of any kind.  Distribution of this

   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   This document provides state machine tables for ATM (Asynchronous

   Transfer Mode) switch LSRs.  In the current LDP specification, there

   is no state machine specified for processing LDP messages. We think

   that defining a common state machine is very important for

   interoperability between different LDP and CR-LDP implementations.

   We begin in section 1 by defining a list of terminologies.  Then in

   section 2, we propose two sets of state machine tables for ATM switch

   LSRs that use downstream-on-demand mode, one method can be used for

   non-vc merge capable ATM LSRs, while the other one can be used for

   the vc-merge capable ATM LSRs.  In section 3, we provides a state

   machine for downstream unsolicited mode ATM LSRs.

   We focus on the LDP state machines and the associated control blocks

   used for establishing and maintaining LSPs.  We do not describe state

   machines for the "LDP controller" that is in charge of LDP session

   initialization, address mapping messages management, routing

   interface, etc. that is defined in the LDP specification.

   Even though the state machines in this document are specific for

   ATM-LSR, they can be easily adapted for other types of LSRs.

Boscher, et al.              Informational                      [Page 1]

RFC 3215                   LDP State Machine                January 2002

Table Of Contents

   1. Terminology ...................................................  4

   2. State Machine for Downstream-on-Demand Mode ...................  4

   2.1 An LSR's Behavior in the Case of a Next Hop Change ...........  4

   2.2. ATM Switch LSR with No VC-merge Capability ..................  5

   2.2.1 LSP Control Block ..........................................  5

   2.2.2 States .....................................................  7

   2.2.3 Events .....................................................  8

   2.2.4 State Transitions ..........................................  9

   2.2.5 State Machine .............................................. 10

   2.2.5.1 State -- "IDLE" .......................................... 10

   2.2.5.2 State -- "RESPONSE_AWAITED" .............................. 13

   2.2.5.3 State -- "ESTABLISHED" ................................... 16

   2.2.5.4 State -- "RELEASE_AWAITED" ............................... 21

   2.2.6 Handling the Next Hop Change ............................... 23

   2.2.6.1 Next Hop Trigger Control Block ........................... 24

   2.2.6.2 States ................................................... 24

   2.2.6.3 Events ................................................... 24

   2.2.6.4 State Transition for next hop change ..................... 25

   2.2.6.5 State Machine .....................................