dst-src-routing & introduction-to-semantic-routing
David Lamparter <equinox@diac24.net> Thu, 28 July 2022 18:31 UTC
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Date: Thu, 28 Jul 2022 17:33:03 +0200
From: David Lamparter <equinox@diac24.net>
To: Routing WG <rtgwg@ietf.org>
Cc: Adrian Farrel <adrian@olddog.co.uk>, Jen Linkova <furry13@gmail.com>, David Lamparter <equinox@diac24.net>, cuilz@szu.edu.cn, yang.shu@szu.edu.cn, xmw@cernet.edu.cn
Subject: dst-src-routing & introduction-to-semantic-routing
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Hi all, just to relay Adrian Farrel's mic comment, that was regarding https://datatracker.ietf.org/doc/draft-farrel-irtf-introduction-to-semantic-routing/ and indeed adding a source lookup is a specific instance of additional routing semantics. Having become aware of that draft only a few minutes ago I of course have not grokked it yet, but in case it aids others in correlating these drafts I'd like to provide 2 pieces of "context": (1.) the "fundamental point" of dst-src-routing is to properly document a common basis of operation and interoperability such that - within the "limited domain" (multihomed enterprise network, cloud service, or homenet) - compatible implementations can be mixed freely. This is also what differentiates this from "policy routing" - aka support for arbitrary routing semantics established by operator input, where the operator also assumes all responsibility for making the end result actually do something useful (or even just non-broken). (2.) for some of the considerations in introduction-to-semantic-routing, there will be nothing corresponding in dst-src-routing - because dst-src-routing only attempts to document forwarding behavior and provide a common basis to routing protocols, but not routing protocol operation itself. If the meaning of a "(D,S)" route itself is fuzzy, any work by a routing protocol to make it interoperable would be futile; or rather the considerations in dst-src-routing would need to be duplicated into each routing protocol. But considerations like actual compatibility mechanisms in the face of non-dst-src-routers or how this impacts convergence are better discussed in the protocol specific documents. The BABEL document for this has in fact passed into RFC: https://datatracker.ietf.org/doc/html/rfc9079 [*] The OSPFv3 and IS-IS ones have met fates similar to the dst-src draft; whether there is use in reviving them is a separate question but regardless of that their contents may contain some useful nuggets of discussion. Cheers, -David [*] due to my failure at pushing dst-src-routing forward, BABEL has substituted [SS-ROUTING: Boutier, M. and J. Chroboczek, "Source-Specific Routing"] as reference. The behavior is fully identical and all considerations are bidirectionally transferrable.
- draft-llsyang-rtgwg-dst-src-routing-00 Jen Linkova
- RE: draft-llsyang-rtgwg-dst-src-routing-00 Les Ginsberg (ginsberg)
- Re: RE: draft-llsyang-rtgwg-dst-src-routing-00 杨术
- Re: draft-llsyang-rtgwg-dst-src-routing-00 Tony Li
- RE: dst-src-routing & introduction-to-semantic-ro… Adrian Farrel
- Re: Re: draft-llsyang-rtgwg-dst-src-routing-00 杨术
- Re: draft-llsyang-rtgwg-dst-src-routing-00 Robert Raszuk
- Re: draft-llsyang-rtgwg-dst-src-routing-00 David Lamparter
- dst-src-routing & introduction-to-semantic-routing David Lamparter
- Re: draft-llsyang-rtgwg-dst-src-routing-00 Jen Linkova