Subject: Alia Atlas' Discuss on draft-ietf-6man-multi-homed-host-07: (with DISCUSS)

From: "Alia Atlas" <[email-masked]>
Date: Tue, 02 Aug 2016 10:55:28 -0700

Alia Atlas has entered the following ballot position for
draft-ietf-6man-multi-homed-host-07: Discuss

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DISCUSS:
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In section 2.2, the document says:

"The direct implication of Section 2.1 is that, if the network uses a
   routing protocol, the routing protocols used in multihomed networks
   SHOULD implement source-prefix based egress routing, for example as
   described in [I-D.ietf-rtgwg-dst-src-routing]."

I understand the desire behind this statement - but find the SHOULD
extremely
strong given that we don't even have any routing protocol extensions
adopted by
ISIS, OPSF or even Babel WGs to handle source-prefix based egress
routing.  
I know that we are actively discussing the problems motivating this
statement
and, I hope, making progress.   However, I don't think that the dynamics
or scaling
or potential looping (for routers that don't support the same source
prefixes) have
been fully described or resolved.

While this problem has been discussed in rtgwg, I do not yet see
consensus in the
Routing Area that this is the agreed solution.  The email sent by v6ops
about this
problem recommended src-dest-routing as a solution and, indeed, that is
being
investigated.

At a minimum, the language in this section needs to change from SHOULD.

---

From: Brian E Carpenter <[email-masked]>
Date: Wed, 3 Aug 2016 07:58:54 +1200

On 03/08/2016 05:55, Alia Atlas wrote:
...
> strong 

Actually, you're right - I don't believe that this draft can make normative
statements about routing practices. I think what we meant here was plain
English "should", not RFC2119 normative SHOULD.

    Brian

> given that we don't even have any routing protocol extensions
> adopted by