Bruno – One of the reasons to use the Binding TLV to advertise the Area SID was that it has been suggested that other use cases for Area SID – unrelated to Area Proxy – may come along. Therefore tying the advertisement to an Area Proxy TLV seems not the best option if we want to allow for these other use cases (admittedly currently unknown).
Thoughts?? Les From: Lsr <lsr-boun...@ietf.org> On Behalf Of bruno.decra...@orange.com Sent: Thursday, July 30, 2020 9:22 AM To: tony...@tony.li; firstname.lastname@example.org Subject: Re: [Lsr] Fwd: New Version Notification for draft-ietf-lsr-isis-area-proxy-02.txt Hi Tony, Thanks for the updated draft. “ The Area SID Sub-TLV allows the Area Leader to advertise a SID that represents the entirety of the Inside Area to the Outside Area. This sub-TLV is learned by all of the Inside Edge Nodes who should consume this SID at forwarding time.” Excellent, from my perspective. * - The Area Segment SID TLV has been replaced by extending the Binding SID TLV. “When SR is enabled, it may be useful to advertise an Area SID which will direct traffic to any of the Inside Edge Routers. The Binding/ MT Binding TLVs described in RFC 8667 Section 2.4<https://tools.ietf.org/html/rfc8667#section-2.4> are used to advertise such a SID. The following extensions to the Binding TLV are defined in order to support Area SID: A new flag is defined: T-flag: The SID directs traffic to an area. (Bit 5) » This works. However I may have a different deployment environment than the one you have in mind. Even if those issues may be mine, allow me to share them with you. In many WAN networks than I’m used to, there are routers from different vendors, platforms, software, generations. Requiring all those routers to support the new Binding SID TLV T-Flag will take time. Some platform may even be end of engineering (evolutions) so would never support such new features. In my environment, ideally, I would prefer a solution which do not require any new feature on external L2 nodes, while all existing L2 features keep working, in particular SR, SR-TE, TI-LFA, SR uloop avoidance… This would require the Proxy LSP to be not (significantly) different than the LSP of a vanilla L2 node. For SR, I think that this would require this Proxy LSP to advertise a Prefix/Node SID with the Area SID attached. One drawback is that a Node-SID is advertised with an IP address that would need to be provisioned. Both approaches are not mutually exclusives. I’d be happy enough with an option for the Proxy LSP to advertise an Area Node SID with the Area SID attached. Finally, there is no requirement to make me happy ;-) . The above could also be a local implementation knob not mentioned in the draft. Thanks, --Bruno From: Lsr [mailto:lsr-boun...@ietf.org] On Behalf Of tony...@tony.li<mailto:tony...@tony.li> Sent: Sunday, July 26, 2020 3:49 AM To: email@example.com<mailto:firstname.lastname@example.org> Subject: [Lsr] Fwd: New Version Notification for draft-ietf-lsr-isis-area-proxy-02.txt Hi folks, This version of the draft reflects major changes in line with the discussions that we’ve had so far. To wit: - The Area Proxy TLV is now moved to be in L2 LSPs and indicates that the advertising node is an Inside Node and Area Proxy is active. - The Area Proxy Router Capability has been removed. - The Inside Node TLV has been removed. - The Area Segment SID TLV has been replaced by extending the Binding SID TLV. We know that some folks disagree with this last point, so we welcome discussion on this. We would like to reach consensus as quickly as possible. Thanks, Tony Begin forwarded message: From: internet-dra...@ietf.org<mailto:internet-dra...@ietf.org> Subject: New Version Notification for draft-ietf-lsr-isis-area-proxy-02.txt Date: July 25, 2020 at 6:46:05 PM PDT To: "Vivek Ilangovan" <ilango...@arista.com<mailto:ilango...@arista.com>>, "Sarah Chen" <sarahc...@arista.com<mailto:sarahc...@arista.com>>, "Gyan S. Mishra" <gyan.s.mis...@verizon.com<mailto:gyan.s.mis...@verizon.com>>, "Gyan Mishra" <gyan.s.mis...@verizon.com<mailto:gyan.s.mis...@verizon.com>>, "Yunxia Chen" <sarahc...@arista.com<mailto:sarahc...@arista.com>>, "Tony Li" <tony...@tony.li<mailto:tony...@tony.li>> A new version of I-D, draft-ietf-lsr-isis-area-proxy-02.txt has been successfully submitted by Tony Li and posted to the IETF repository. Name: draft-ietf-lsr-isis-area-proxy Revision: 02 Title: Area Proxy for IS-IS Document date: 2020-07-25 Group: lsr Pages: 20 URL: https://www.ietf.org/internet-drafts/draft-ietf-lsr-isis-area-proxy-02.txt Status: https://datatracker.ietf.org/doc/draft-ietf-lsr-isis-area-proxy/ Htmlized: https://tools.ietf.org/html/draft-ietf-lsr-isis-area-proxy-02 Htmlized: https://datatracker.ietf.org/doc/html/draft-ietf-lsr-isis-area-proxy Diff: https://www.ietf.org/rfcdiff?url2=draft-ietf-lsr-isis-area-proxy-02 Abstract: Link state routing protocols have hierarchical abstraction already built into them. However, when lower levels are used for transit, they must expose their internal topologies to each other, leading to scale issues. To avoid this, this document discusses extensions to the IS-IS routing protocol that would allow level 1 areas to provide transit, yet only inject an abstraction of the level 1 topology into level 2. Each level 1 area is represented as a single level 2 node, thereby enabling greater scale. Please note that it may take a couple of minutes from the time of submission until the htmlized version and diff are available at tools.ietf.org<http://tools.ietf.org>. The IETF Secretariat _________________________________________________________________________________________________________________________ Ce message et ses pieces jointes peuvent contenir des informations confidentielles ou privilegiees et ne doivent donc pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce message par erreur, veuillez le signaler a l'expediteur et le detruire ainsi que les pieces jointes. Les messages electroniques etant susceptibles d'alteration, Orange decline toute responsabilite si ce message a ete altere, deforme ou falsifie. Merci. 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