Huaimo -
The question I and others have asked is "what can we do with zones that cannot
be done with areas?".
>From the day several years ago when IS-IS TTZ was first presented, your
>answer has been "with zones you can hitlessly alter the topological
>boundaries".
My response has consistently been "we can already do that with areas".
If you want to justify zones, you then need to provide some other use case that
either cannot be done using areas or cannot be done hitlessly.
Continuing to focus on something that can already be done with areas isn't
helping you.
Les
From: Huaimo Chen <huaimo.c...@futurewei.com>
Sent: Tuesday, August 18, 2020 3:18 PM
To: Les Ginsberg (ginsberg) <ginsb...@cisco.com>; Les Ginsberg (ginsberg)
<ginsberg=40cisco....@dmarc.ietf.org>; Acee Lindem (acee)
<acee=40cisco....@dmarc.ietf.org>; lsr@ietf.org
Subject: Re: LSR WG Adoption Poll for "IS-IS Topology-Transparent Zone" -
draft-chen-isis-ttz-11.txt
Hi Les,
> It is possible to merge/split areas without adjacency flaps.
[HC]: While an existing area or zone is being abstracted as a single node
or vice versa, there are the adjacency ups and downs. The areas
merging/splitting without adjacency flaps has been done before this abstraction
and will not reduce the service interruption during the abstraction.
Best Regards,
Huaimo
________________________________
From: Les Ginsberg (ginsberg) <ginsb...@cisco.com<mailto:ginsb...@cisco.com>>
Sent: Tuesday, August 18, 2020 5:59 PM
To: Huaimo Chen <huaimo.c...@futurewei.com<mailto:huaimo.c...@futurewei.com>>;
Les Ginsberg (ginsberg)
<ginsberg=40cisco....@dmarc.ietf.org<mailto:ginsberg=40cisco....@dmarc.ietf.org>>;
Acee Lindem (acee)
<acee=40cisco....@dmarc.ietf.org<mailto:acee=40cisco....@dmarc.ietf.org>>;
lsr@ietf.org<mailto:lsr@ietf.org> <lsr@ietf.org<mailto:lsr@ietf.org>>
Subject: RE: LSR WG Adoption Poll for "IS-IS Topology-Transparent Zone" -
draft-chen-isis-ttz-11.txt
Huaimo -
It is possible to merge/split areas without adjacency flaps.
The technique has been known for many years.
It requires careful planning - but it is quite feasible and has been done.
You cannot justify the need for zones on this basis.
Les
From: Lsr <lsr-boun...@ietf.org<mailto:lsr-boun...@ietf.org>> On Behalf Of
Huaimo Chen
Sent: Tuesday, August 18, 2020 2:33 PM
To: Les Ginsberg (ginsberg)
<ginsberg=40cisco....@dmarc.ietf.org<mailto:ginsberg=40cisco....@dmarc.ietf.org>>;
Acee Lindem (acee)
<acee=40cisco....@dmarc.ietf.org<mailto:acee=40cisco....@dmarc.ietf.org>>;
lsr@ietf.org<mailto:lsr@ietf.org>
Subject: Re: [Lsr] LSR WG Adoption Poll for "IS-IS Topology-Transparent Zone" -
draft-chen-isis-ttz-11.txt
Hi Les,
> I see no need for "abstraction at arbitrary boundaries". Areas work just fine.
> IS-IS already has smooth transition capability for merging/splitting areas..
[HC]: The smooth transition capability for merging/splitting areas in IS-IS
will not reduce the service interruption while an existing area or zone is
being abstracted as a single node because the adjacency ups and downs.
> Given both of the points above, I see no value in "smooth transition to/from
> zone abstraction".
[HC]: The "smooth transition to/from zone abstraction" will reduce the service
interruption while an existing area or zone is being abstracted as a single
node and vice versa.
Best Regards,
Huaimo
________________________________
From: Lsr <lsr-boun...@ietf.org<mailto:lsr-boun...@ietf.org>> on behalf of Les
Ginsberg (ginsberg)
<ginsberg=40cisco....@dmarc.ietf.org<mailto:ginsberg=40cisco....@dmarc.ietf.org>>
Sent: Tuesday, August 18, 2020 5:06 PM
To: Acee Lindem (acee)
<acee=40cisco....@dmarc.ietf.org<mailto:acee=40cisco....@dmarc.ietf.org>>;
lsr@ietf.org<mailto:lsr@ietf.org> <lsr@ietf.org<mailto:lsr@ietf.org>>
Subject: Re: [Lsr] LSR WG Adoption Poll for "IS-IS Topology-Transparent Zone" -
draft-chen-isis-ttz-11.txt
I see no need for "abstraction at arbitrary boundaries". Areas work just fine.
IS-IS already has smooth transition capability for merging/splitting areas.
Given both of the points above, I see no value in "smooth transition to/from
zone abstraction".
If these are the principal distinguishing characteristics of TTZ as compared to
area proxy (and I would agree they are), then I see no reason why this solution
should be pursued as well.
I am therefore opposed to WG adoption of TTZ.
Les
From: Lsr <lsr-boun...@ietf.org<mailto:lsr-boun...@ietf.org>> On Behalf Of Acee
Lindem (acee)
Sent: Tuesday, August 18, 2020 7:17 AM
To: lsr@ietf.org<mailto:lsr@ietf.org>
Subject: [Lsr] LSR WG Adoption Poll for "IS-IS Topology-Transparent Zone" -
draft-chen-isis-ttz-11.txt
Based on the discussions in the last meeting and on the mailing list regarding
draft-chen-isis-ttz-11, the chairs feel that there are enough differences with
draft-ietf-lsr-isis-area-proxy-03 and in the community to consider advancing it
independently on the experimental track.
These differences include abstraction at arbitrary boundaries and IS-IS
extensions for smooth transition to/from zone abstraction.
We are now starting an LSR WG adoption call for draft-chen-isis-ttz-11.txt.
Please indicate your support or objection to adoption prior to Tuesday,
September 2nd, 2020.
Thanks,
Acee and Chris
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