Went last nits with Les, we found one issue (encaps section was wrong, need to look @ OSPF as well) and basically tightened language in few places. tony
On Tue, Feb 6, 2018 at 3:45 PM, Greg Shepherd <[email protected]> wrote: > Thanks Les. > > Any other feedback? Looks like the concerns have been addressed. Speak now. > > Cheers, > Greg > > On Thu, Feb 1, 2018 at 7:26 AM, Les Ginsberg (ginsberg) < > [email protected]> wrote: > >> Greg – >> >> >> >> This thread is outdated. >> >> In V6 of the draft we removed the restriction to limit IS-IS BIER support >> to area boundaries – so Toerless’s comment (and my proposed text) are no >> longer relevant. >> >> >> >> Specifically: >> >> >> >> Section 4.1: >> >> >> >> “At present, IS-IS support for a given BIER domain/sub-domain >> is >> >> limited to a single area - or to the IS-IS L2 >> sub-domain.” >> >> >> >> The above text was removed. >> >> >> >> Section 4.2 >> >> >> >> o BIER sub-TLVs MUST NOT be included when a prefix reachability >> >> advertisement is leaked between levels. >> >> >> >> Was changed to >> >> >> >> o BIER sub-TLVs MUST be included when a prefix reachability >> >> advertisement is leaked between levels. >> >> >> >> This aligns IS-IS and OSPF drafts in this regard. >> >> >> >> Les >> >> >> >> *From:* Greg Shepherd [mailto:[email protected]] >> *Sent:* Thursday, February 01, 2018 2:23 AM >> *To:* Toerless Eckert <[email protected]> >> *Cc:* Les Ginsberg (ginsberg) <[email protected]>; Tony Przygienda < >> [email protected]>; Hannes Gredler ([email protected]) < >> [email protected]>; [email protected]; [email protected] list < >> [email protected]>; Christian Hopps <[email protected]> >> >> *Subject:* Re: [Bier] WGLC: draft-ietf-bier-isis-extensions-04 >> >> >> >> Have these changes been reflected in the draft? We're in WGLC but this >> discussion needs to come to a conclusion so we can progress. >> >> >> >> Greg >> >> >> >> On Tue, Jul 25, 2017 at 12:52 PM, Toerless Eckert <[email protected]> wrote: >> >> Thanks, Less, that would be lovely! >> >> I didn't check the OSPF draft, if its similar state, explanatory text >> wold equally be appreciated. >> >> >> On Sun, Jul 23, 2017 at 11:28:08PM +0000, Les Ginsberg (ginsberg) wrote: >> > Toerless - >> > >> > I am thinking to add a statement in Section 4.1 - something like: >> > >> > "At present, IS-IS support for a given BIER domain/sub-domain is >> limited to a single area - or to the IS-IS L2 sub-domain." >> > >> > If you believe this would be helpful I will spin a new version (subject >> to review/agreement from my co-authors). >> > >> > Les >> > >> > >> > > -----Original Message----- >> > > From: Toerless Eckert [mailto:[email protected]] >> > > Sent: Saturday, July 22, 2017 6:34 AM >> > > To: Les Ginsberg (ginsberg) >> > > Cc: Tony Przygienda; Hannes Gredler ([email protected]); Greg >> Shepherd; >> > > [email protected]; [email protected] list; Christian Hopps >> > > Subject: Re: [Bier] WGLC: draft-ietf-bier-isis-extensions-04 >> > > >> > > Thanks Les >> > > >> > > When searching various terms in the doc to figure out what happens i >> am not >> > > sure why i missed this one. >> > > >> > > But: IMHO, RFCs can not only be the minimum number of words to get a >> > > running implementation. It also needs to specify what this >> implementation >> > > intends to achieve. Otherwise its not possible to do a useful review: >> > > The reviewer can to verify whether the spec will achieve what it >> claims to >> > > achieve is there no definitionn of what it claims to achieve. >> > > >> > > If i understand ISIS correctly, my reverse engineering of the intent >> is: >> > > >> > > - BIER TLVs stay within single ISIS areas. BFIR and BFER must >> therefore be >> > > in the same ISIS area: There is no inter-area BIER traffic possible >> > > with this specification. This is also true for ISIS area 0. >> > > >> > > - The same BIER sub-domain identifiers can be re-used >> > > across different ISIS areas without any current impact. If these >> BFR-IDs >> > > are non-overlapping, then this would allow in the future to create >> a single >> > > cross ISIS area BIER sub-domain by leaking TLVs for such a BIER >> sub-domain >> > > across ISIS levels. Leakage is outside the scope of this >> specificication. >> > > >> > > I actually even would like to do the following: >> > > >> > > - If BIER sub-domains are made to span multiple ISIS areas and BFR-ids >> > > assignemtns >> > > are made such that all BFR-ids with the same SI are in the same >> ISIS ara, >> > > then it should be in the future reasonably easy to create >> inter-area BIER >> > > not by leaking of the BIER TLV but by having BFIR MPLS unicastBIER >> packets >> > > for different SIs to an appropriate L2L1 BFIR that is part of the >> destination >> > > area/SI. >> > > (if you would use SI number that are the same as ISIS area numbers >> then >> > > you could probably do this without any new signaling. Not quite >> sure if >> > > you can today easily find L1L2 border router for another area via >> existing >> > > TLVs). >> > > >> > > Alas, this idea will probably be killed because of the BIER >> architecture >> > > intent not to engineer SI assignments in geographical fashions to >> > > minimize traffic duplication in the presence of multiple SIs. >> > > >> > > Cheers >> > > Toerless >> > > >> > > On Sat, Jul 22, 2017 at 06:03:53AM +0000, Les Ginsberg (ginsberg) >> wrote: >> > > > Tony/Toerless ??? >> > > > >> > > > There is an explicit statement as to scope: >> > > > >> > > > <snip> >> > > > Section 4.2 >> > > > ??? >> > > > o BIER sub-TLVs MUST NOT be included when a prefix reachability >> > > > advertisement is leaked between levels. >> > > > <end snip> >> > > > >> > > > Tony seems to have forgotten that we had a discussion about how BIER >> > > might be supported across areas and the conclusion was we did not know >> > > how to do that yet. >> > > > (Sorry Tony) >> > > > >> > > > Note this is ???consistent??? with https://www.ietf.org/id/draft- >> ietf-bier- >> > > ospf-bier-extensions-07.txt Section 2.5<https://www.ietf.org/id/dr >> aft-ietf- >> > > bier-ospf-bier-extensions-07.txt%20Section%202.5> - which limits the >> > > flooding scope of BIER information to a single area unless it can be >> validated >> > > that the best path to the prefix with BIER info can be validated to >> be to a >> > > router which itself advertised the BIER info. This is not something >> IS-IS can do >> > > since a single IS-IS instance only supports one area and therefore >> does not >> > > have the Level-1 advertisements of the originating router when that >> router is >> > > in another area. >> > > > >> > > > A few more responses inline. >> > > > >> > > > From: BIER [mailto:[email protected]] On Behalf Of Tony >> Przygienda >> > > > Sent: Friday, July 21, 2017 5:17 AM >> > > > To: Toerless Eckert >> > > > Cc: Hannes Gredler ([email protected]); Greg Shepherd; >> [email protected]; >> > > > [email protected] list; Christian Hopps >> > > > Subject: Re: [Bier] WGLC: draft-ietf-bier-isis-extensions-04 >> > > > >> > > > Terminology is a bit nits IMO since the doc is reading clear >> enough for >> > > someone who read BIER & ISIS. I can reread it or Les can comment >> whether >> > > we should tighten glossary ... >> > > > >> > > > With the scope I agree, that got lost and the doc should be >> possibly rev'ed >> > > before closing LC. Yes, we flood AD wide was the agreement but >> something >> > > mentioning that this could change in the future is good so we are >> forced to >> > > give it some thought how that would transition ... >> > > > >> > > > Thinking further though, in ISIS we have a clean document really. >> The BIER >> > > sub-TLVs go into well defined TLVs in terms of flooding scope. Normal >> L1-L2 >> > > redistribution can be used to get the info to all needed places >> AFAIS. So >> > > maybe nothing needs to be written. I wait for Les to chime in. >> > > > >> > > > OSPF I would have to look @ scopes again & think whether we need to >> > > write something or maybe Peter can comment ... >> > > > >> > > > --- tony >> > > > >> > > > >> > > > >> > > > On Fri, Jul 21, 2017 at 8:27 AM, Toerless Eckert >> > > <[email protected]<mailto:[email protected]>> wrote: >> > > > Sorry, past the two weeks, but hopefully benign textual comments: >> > > > >> > > > We tried to find an explicit statement about the scope of BIER TLVs >> - eg: >> > > > are they meant to stay within an area, have some redistribution >> across >> > > > areas/levels or not. >> > > > >> > > > Tony said WG agreement was to have these TLV be flooded across the >> > > > whole ISIS domain for now (this draft). So an explicit statement to >> that >> > > effect would >> > > > be great (All BIER sub-domains TLVs are flooded across all ISIS >> areas/levels, >> > > so they span the whole ISIS domain). >> > > > >> > > > Also, if future work may/should could improve on that maybe some >> > > > sentence about that (i guess one could just have ISIS intra-area >> BIER sub- >> > > domains ?). >> > > > >> > > > Also: Do a check about possible ambiguity of any generic terms like >> > > sub-domain, level, area, topology so that reader that don't know the >> > > terminology ofall protocols (ISIS, BIER) by heart can easily know >> which >> > > protocol is referred to. >> > > > >> > > > [Les:] There is no mention of ???level??? in the document. >> > > > The use of ???sub-domain??? is clearly always associated with >> ???BIER???. >> > > > ???topology??? is always used as an RFC 5120 topology ??? therefore >> > > clearly an IS-IS topology. >> > > > There is only one use of the term ???area??? (in Section 5.1). That >> text >> > > might deserve a bit of clarification given this might be either a >> Level 1 area or >> > > the Level2 sub-domain. I???ll take a pass at it. >> > > > (BTW ??? I am talking about IS-IS area/L2sub-domain Toerless. ???) >> > > > >> > > > I don???t see that any other clarification is needed ??? but >> Toerless ??? if >> > > you can point to any specific sentences/paragraphs which you find >> confusing >> > > - I???ll take a second look. >> > > > >> > > > Les >> > > > >> > > > >> > > > I guess there are no BIER level, area or topologies, but still makes >> > > > reading easier if the doc would say "ISIS level", "ISIS area", or at >> > > > least have them in the Terminology section. And probably in >> > > > terminology say "domain -> in the context of this document the BIER >> > > domain which is also the same as the ISIS domain" >> > > > (which i hope is the correct statement, see above). >> > > > >> > > > Cheers >> > > > Toerless >> > > > >> > > > _______________________________________________ >> > > > BIER mailing list >> > > > [email protected]<mailto:[email protected]> >> > > > https://www.ietf.org/mailman/listinfo/bier >> > > > >> > > > >> > > > >> > > > -- >> > > > We???ve heard that a million monkeys at a million keyboards could >> > > produce the complete works of Shakespeare; now, thanks to the >> Internet, >> > > we know that is not true. >> > > > ???Robert Wilensky >> > > >> > > -- >> > > --- >> > > [email protected] >> >> >> > >
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