RFC 3847 (rfc3847) - Page 2 of 21

Restart Signaling for Intermediate System to Intermediate System (IS-IS)

Alternative Format: Original Text Document
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RFC 3847              Restart signaling for IS-IS              July 2004


Table of Contents

   1.  Conventions used in this Document. . . . . . . . . . . . . . .  2
   2.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Approach . . . . . . . . . . . . . . . . . . . . . . . . . . .  4
       3.1.  Timers . . . . . . . . . . . . . . . . . . . . . . . . .  4
       3.2.  Restart TLV. . . . . . . . . . . . . . . . . . . . . . .  5
             3.2.1.  Use of RR and RA Bits. . . . . . . . . . . . . .  6
             3.2.2.  Use of SA Bit. . . . . . . . . . . . . . . . . .  7
       3.3.  Adjacency (re)Acquisition. . . . . . . . . . . . . . . .  8
             3.3.1.  Adjacency Reacquisition During Restart . . . . .  8
             3.3.2.  Adjacency Acquisition During Start . . . . . . . 10
             3.3.3.  Multiple Levels. . . . . . . . . . . . . . . . . 12
       3.4.  Database Synchronization . . . . . . . . . . . . . . . . 12
             3.4.1.  LSP Generation and Flooding and SPF Computation. 13
                     3.4.1.1. Restarting. . . . . . . . . . . . . . . 13
                     3.4.1.2. Starting. . . . . . . . . . . . . . . . 15
   4.  State Tables . . . . . . . . . . . . . . . . . . . . . . . . . 15
       4.1.  Running Router . . . . . . . . . . . . . . . . . . . . . 16
       4.2.  Restarting Router. . . . . . . . . . . . . . . . . . . . 17
       4.3.  Starting Router. . . . . . . . . . . . . . . . . . . . . 18
   5.  Security Considerations. . . . . . . . . . . . . . . . . . . . 18
   6.  IANA Considerations. . . . . . . . . . . . . . . . . . . . . . 19
   7.  Normative References . . . . . . . . . . . . . . . . . . . . . 19
   8.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 20
   9.  Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 20
   10. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 21

1.  Conventions used in this Document

   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 BCP 14, RFC-2119 [3].

   If the control and forwarding functions in a router can be maintained
   independently, it is possible for the forwarding function state to be
   maintained across a resumption of control function operations.  This
   functionality is assumed when the terms "restart/restarting" are used
   in this document.

   The terms "start/starting" are used to refer to a router in which the
   control function has either commenced operations for the first time
   or has resumed operations but the forwarding functions have not been
   maintained in a prior state.

   The terms "(re)start/(re)starting" are used when the text is
   applicable to both a "starting" and a "restarting" router.




Shand & Ginsberg             Informational
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