Shortest Path First (SPF) Back-Off Delay Algorithm for Link-State IGPs
RFC 8405
Document | Type | RFC - Proposed Standard (June 2018; No errata) | |
---|---|---|---|
Authors | Bruno Decraene , Stephane Litkowski , Hannes Gredler , Acee Lindem , Pierre Francois , Chris Bowers | ||
Last updated | 2018-12-19 | ||
Replaces | draft-decraene-rtgwg-backoff-algo | ||
Stream | Internent Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Reviews | |||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Uma Chunduri | ||
Shepherd write-up | Show (last changed 2018-01-22) | ||
IESG | IESG state | RFC 8405 (Proposed Standard) | |
Action Holders |
(None)
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||
Consensus Boilerplate | Yes | ||
Telechat date | |||
Responsible AD | Alia Atlas | ||
Send notices to | Uma Chunduri <uma.chunduri@huawei.com> | ||
IANA | IANA review state | Version Changed - Review Needed | |
IANA action state | No IANA Actions |
Internet Engineering Task Force (IETF) B. Decraene Request for Comments: 8405 Orange Category: Standards Track S. Litkowski ISSN: 2070-1721 Orange Business Service H. Gredler RtBrick Inc. A. Lindem Cisco Systems P. Francois C. Bowers Juniper Networks, Inc. June 2018 Shortest Path First (SPF) Back-Off Delay Algorithm for Link-State IGPs Abstract This document defines a standard algorithm to temporarily postpone or "back off" link-state IGP Shortest Path First (SPF) computations. This reduces the computational load and churn on IGP nodes when multiple temporally close network events trigger multiple SPF computations. Having one standard algorithm improves interoperability by reducing the probability and/or duration of transient forwarding loops during the IGP convergence when the IGP reacts to multiple temporally close IGP events. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8405. Decraene, et al. Standards Track [Page 1] RFC 8405 SPF Back-Off Delay Algorithm June 2018 Copyright Notice Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. High-Level Goals . . . . . . . . . . . . . . . . . . . . . . 3 3. Definitions and Parameters . . . . . . . . . . . . . . . . . 4 4. Principles of the SPF Delay Algorithm . . . . . . . . . . . . 5 5. Specification of the SPF Delay State Machine . . . . . . . . 6 5.1. State Machine . . . . . . . . . . . . . . . . . . . . . . 6 5.2. States . . . . . . . . . . . . . . . . . . . . . . . . . 7 5.3. Timers . . . . . . . . . . . . . . . . . . . . . . . . . 7 5.4. FSM Events . . . . . . . . . . . . . . . . . . . . . . . 7 6. Parameters . . . . . . . . . . . . . . . . . . . . . . . . . 9 7. Partial Deployment . . . . . . . . . . . . . . . . . . . . . 10 8. Impact on Micro-loops . . . . . . . . . . . . . . . . . . . . 11 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 10. Security Considerations . . . . . . . . . . . . . . . . . . . 11 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 11.1. Normative References . . . . . . . . . . . . . . . . . . 11 11.2. Informative References . . . . . . . . . . . . . . . . . 11 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 Decraene, et al. Standards Track [Page 2] RFC 8405 SPF Back-Off Delay Algorithm June 2018 1. Introduction Link-state IGPs, such as IS-IS [ISO10589], OSPF [RFC2328], and OSPFv3 [RFC5340], perform distributed route computation on all routers in the area/level. In order to have consistent routing tables across the network, such distributed computation requires that all routers have the same version of the network topology (Link-State Database (LSDB)) and perform their computation essentially at the same time.Show full document text