Hi Bruno, Thanks for your comments.
About the first point, we do have use cases where the bandwidth is not what we want to encode in the EC but rather a generalized weight that is derived from the link count, logical weight or simply a configured value. Among the co-authors we also discussed the possibility of defining two ECs: one for BW and one for a generalized-weight, so that the remote PE can catch if the multi-homed PEs were indeed using the same meaning of the weight. However, we thought it was easier/simpler to use a generalized value in a single EC sub-type, and add the sentence below. The sentence can be modified/fixed. But the gist is that the multi-homed PEs may support multiple meanings for the weight (BW, link-count, etc), but at least one of those MUST be common across all PEs and the multi-homed routes must use it consistently. Would it be enough if we fix it? About existing implementations, a new EVPN sub-type was defined only a couple of revisions ago, where, before, the existing non-transitive link BW EC was used, so there’s been some churn in the use of the EC anyway. I think it is important to get it as soon as possible, but get it right rather than finding gaps later once the document is done. But let us know your thoughts too. Thank you. Jorge From: BESS <bess-boun...@ietf.org> on behalf of bruno.decra...@orange.com <bruno.decra...@orange.com> Date: Thursday, May 6, 2021 at 10:04 AM To: Neeraj Malhotra <neeraj.i...@gmail.com> Cc: slitkows.i...@gmail.com <slitkows.i...@gmail.com>, bess@ietf.org <bess@ietf.org> Subject: Re: [bess] New short WGLC for draft-ietf-bess-evpn-unequal-lb Hi Neeraj, Thanks for considering my comments. Much better from my perspective. Thank you. I have two comments on the changes: - Regarding deployments §4.1 allows two rather incompatible encodings/usages with no way to detect which one is used: some PE could advertise the bandwidth in bytes, while some other PE could advertise a general weight. I understand that both works, but to me there is a significant risk of issues over time or between domain/SP. I’d prefer that you only chose one in order to favour consistency in deployments and usage and I would prefer the real bandwidth (at least for consistency with the name of the community, but also because this is not subjective) (And if a SP really wants to put an arbitrary value, I think he will figure out by himself, that it can do so). If you disagree with the above, then I would have a comment on the two below sentences: An implementation may support one or more of the above ways of encoding the value. Operator MUST ensure consistent encoding of this value across all PEs in an ethernet segment. Logic dictates that the second sentence (MUST) can only be fulfilled if the first sentence mandates that all implementations MUST support both options, or one specifically defined. - Regarding existing implementations: previous version of the draft did not really specify the format of the EVPN EC. I had personally assumed that the format was similar to the draft-ietf-idr-link-bandwidth link bandwidth community hence encoded in IEEE floating point format. Latest version of the draft defines it in unsigned integer. Integer looks good to me, but for an existing implementation this may be seen as an incompatible change very late in the process. Obviously, if there are no implementation, there is no issue. In which case, you could also express the bandwidth in unit of bit/s _if you_ wish to. (I have no preference). However given that the draft had indicated a codepoint, there seem to be a risk of existing implementations hence incompatible change. BTW the codepoint is squatted even though the registry is FCFS hence easy to request. Thanks, --Bruno From: Neeraj Malhotra [mailto:neeraj.i...@gmail.com] Sent: Thursday, May 6, 2021 7:41 AM To: DECRAENE Bruno TGI/OLN <bruno.decra...@orange.com> Cc: slitkows.i...@gmail.com; bess@ietf.org Subject: Re: [bess] New short WGLC for draft-ietf-bess-evpn-unequal-lb Hi Bruno, Many thanks for the review comments. We have revised the draft addressing your comments. More inline. Thanks, Neeraj On Mon, May 3, 2021 at 2:20 AM <bruno.decra...@orange.com<mailto:bruno.decra...@orange.com>> wrote: Hi Stéphane, authors, I have not followed the discussions on this document, but I’ll nonetheless raise one point regarding the bandwidth community (better safe than sorry). - why has [BGP-LINK-BW] been moved to informational reference while its reading seem mandatory? [NM]: There was a leftover reference to this in one of the sections that has been fixed now to use new EVPN EC. With this, reference to [BGP-LINK-BW] is purely informational (as was intended). - A new EVPN Link Bandwidth extended community is defined, but I could not find its specification. I guess that this is the same format as [BGP-LINK-BW] but transitive. Could this be explicitly stated? [NM]: clarified in section 4. - [BGP-LINK-BW] advertises the bandwidth in unit of bytes (not bits!) per second. Could the unit of the new EVPN Link Bandwidth extended community be also clearly spelled out? Especially give the history on this (cf below). Also in order to avoid misleading the readers could the examples use the correct unit (vs bits per seconds as writen) [NM]: done. - 10 years ago or so, I had raised a similar point (distinction between bits and bytes) on [BGP-LINK-BW] in the IDR WG. And it turned out that 1 major implementation had implemented and deployed “bytes per second” as per the spec, while another implementation had implemented and deployed “bits per second” which is the typical unit of link bandwidth. Given the deployments, none was willing to change its implementation as it would be a non-backward compatible change with themselves. What’s the status on this? Could we have an implementation status on this? [NM]: I don't have this information. Perhaps someone else could comment. Thanks Regards, --Bruno From: BESS [mailto:bess-boun...@ietf.org<mailto:bess-boun...@ietf.org>] On Behalf Of slitkows.i...@gmail.com<mailto:slitkows.i...@gmail.com> Sent: Monday, May 3, 2021 9:21 AM To: bess@ietf.org<mailto:bess@ietf.org> Subject: [bess] New short WGLC for draft-ietf-bess-evpn-unequal-lb Hi WG, We got final updates from authors on draft-ietf-bess-evpn-unequal-lb. I'm opening a new short Working Group Last Call (to be closed on 5/10) to get any last comments before moving to the next step. However, the document having normative references to EVPN PREF DF, and PER-MCAST-FLOW-DF, the draft will not be sent to IESG until these drafts are ready. Feel free to send comments to the list before next Monday. Thanks, Stephane https://datatracker.ietf.org/doc/draft-ietf-bess-evpn-unequal-lb/ _________________________________________________________________________________________________________________________ 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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