Subject: [trill] Suresh Krishnan's Discuss on draft-ietf-trill-irb-13: (with DISCUSS and COMMENT)

From: "Suresh Krishnan" <[email-masked]>
Date: Wed, 29 Jun 2016 16:08:35 -0700

Suresh Krishnan has entered the following ballot position for
draft-ietf-trill-irb-13: Discuss

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DISCUSS:
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* Section 6 has a few errors that need to get fixed before this document
goes forward. e.g. It is not clear what a "192.0.2.0/32" subnet means
especially since the only host shown to be on the subnet 192.0.2.2 cannot
obviously fall inside the subnet range. The /32 needs to be replaced with
something shorter depending on what the authors/WG intended (say a /24).
* RB2 seems to be advertising ES2s IPv4 address 198.51.100.2/32 instead
of the prefix of the subnet while RB1 seems to be advertising the the
IPv4 prefix of the ES1 subnet. One of these is wrong. Not sure which one
is intended.
* What is the rationale for using a /112 IPv6 prefix for numbering an
IPv6 link with hosts? Things like SLAAC (RFC4862) will not work in such
links. Is there a reason the authors want to use a longer than /64?
Please read RFC7421 for advantages of using a /64 instead and to find out
what things break if you do not use a /64.

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COMMENT:
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Section 5: What does "Layer 2 routing" mean in this context?
Sections 7.3 & 7.4: What is the point of including these sub-TLVs if no
prefix is being advertised? (The Total Length=0 case specified in the
document)

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From: Donald Eastlake <[email-masked]>
Date: Thu, 30 Jun 2016 14:13:02 -0400

Hi Suresh,

Thanks for your comments. See below.

On Wed, Jun 29, 2016 at 7:08 PM, Suresh Krishnan
<[email-masked]> wrote:
> ...

Yes. That should have been "/24".

> IPv4 prefix of the ES1 subnet. One of these is wrong. Not sure which one

It should be the prefix in both cases.

> what things break if you do not use a /64.

The Distributed Layer 3 gateway specified in this draft is expect to
primarily be used in data centers where I would expect everything to
be strictly configured by an orchestration system. Thus stateless
autoconfiguration seems less likely and I suspect it just wasn't
through of. However, I don't see a problem with changing this to "/64"
and the mechanism specified could be used in other contexts outside
data centers.

Previously standardized TRILL routing, which is based on destination
MAC address as mapped into a TRILL nickname. The wording can be
clarified.

> prefix is being advertised? (The Total Length=0 case specified in the

Sometimes a zero length has some special meaning. The draft just says
that it has the obvious meaning although it is not a particularly
useful value.

Thanks,
Donald
===============================
 Donald E. Eastlake 3rd   +1-508-333-2270 (cell)
 155 Beaver Street, Milford, MA 01757 USA
 [email-masked]

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From: Suresh Krishnan <[email-masked]>
Date: Fri, 1 Jul 2016 03:14:35 +0000

Hi Donald,
   Your proposed changes and clarifications look good to me. I will look over 
the new version when it is posted.

Thanks
Suresh