Re: [homenet] dst/src routing drafts (for IETF-91 rtgwg)

Brian E Carpenter <> Tue, 28 October 2014 19:52 UTC

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Date: Wed, 29 Oct 2014 08:52:18 +1300
From: Brian E Carpenter <>
Organization: University of Auckland
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To: Ole Troan <>
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Cc: David Lamparter <>, "" <>, "" <>, "Fred Baker \(fred\)" <>, Mikael Abrahamsson <>
Subject: Re: [homenet] dst/src routing drafts (for IETF-91 rtgwg)
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On 29/10/2014 02:06, Ole Troan wrote:
> Fred,
>> Speaking strictly for myself, I’m not sure why homenet is relevant. The technology is related to networks that have different routing depend on on one’s use case. A class of solutions for it has been called the “fish” problem, and built using multi-topology routing. In homenet, it’s called SADR, and is primarily about egress routing (routing to an egress to an upstream ISP that gave you a PA prefix). While one doesn’t really want to confuse theory with practice, in theory it could be used between points of a network, to prevent folks using one set of prefixes to talk with another set, or to force routing of some sessions in some ways.
>> Personally, those are a class of problems I associate with campus networks more than residential networks.
> why homenet is relevant?
> isn't multi-prefix multi-homing one of the most obvious use cases for source address dependent routing? that's not restricted with homenets, but also any small network. I'm assuming large networks will continue with PI addresses and BGP based multihoming.

If you mean by "large" the few ten thousand largest networks in the
world, that will not cause significant BGP4 bloat by having PI, then
yes, I fully agree. Any medium to small network should expect to have
multiple prefixes in the long run (we are not talking about today, but
a time when all we old folks who remember the IPv4 world have retired
and gone fishing).