RFC 3847 (rfc3847) - Page 2 of 21
Restart Signaling for Intermediate System to Intermediate System (IS-IS)
Alternative Format: Original Text Document
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