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> On Behalf Of Huaimo Chen Sent: Tuesday, August 18, 2020 2:33 PM To: Les Ginsberg (ginsberg) <ginsberg=40cisco....@dmarc.ietf.org>; Acee Lindem (acee) <acee=40cisco....@dmarc.ietf.org>; 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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