Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-extensions-04
Toerless Eckert <tte@cs.fau.de> Tue, 25 July 2017 19:52 UTC
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Date: Tue, 25 Jul 2017 21:52:11 +0200
From: Toerless Eckert <tte@cs.fau.de>
To: "Les Ginsberg (ginsberg)" <ginsberg@cisco.com>
Cc: Tony Przygienda <tonysietf@gmail.com>, "Hannes Gredler (hannes@gredler.at)" <hannes@gredler.at>, Greg Shepherd <gjshep@gmail.com>, "bier@ietf.org" <bier@ietf.org>, "isis-wg@ietf.org list" <isis-wg@ietf.org>, Christian Hopps <chopps@chopps.org>
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Subject: Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-extensions-04
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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:tte@cs.fau.de] > > Sent: Saturday, July 22, 2017 6:34 AM > > To: Les Ginsberg (ginsberg) > > Cc: Tony Przygienda; Hannes Gredler (hannes@gredler.at); Greg Shepherd; > > bier@ietf.org; isis-wg@ietf.org 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/draft-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:bier-bounces@ietf.org] On Behalf Of Tony Przygienda > > > Sent: Friday, July 21, 2017 5:17 AM > > > To: Toerless Eckert > > > Cc: Hannes Gredler (hannes@gredler.at); Greg Shepherd; bier@ietf.org; > > > isis-wg@ietf.org 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 > > <tte@cs.fau.de<mailto:tte@cs.fau.de>> 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 > > > BIER@ietf.org<mailto:BIER@ietf.org> > > > 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 > > > > -- > > --- > > tte@cs.fau.de
- [Isis-wg] WGLC: draft-ietf-bier-isis-extensions-04 Greg Shepherd
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Toerless Eckert
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Tony Przygienda
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Les Ginsberg (ginsberg)
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Toerless Eckert
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Tony Przygienda
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Les Ginsberg (ginsberg)
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Toerless Eckert
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Greg Shepherd
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Les Ginsberg (ginsberg)
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Greg Shepherd
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Greg Shepherd
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… IJsbrand Wijnands (iwijnand)
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Tony Przygienda
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Greg Shepherd
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Tony Przygienda
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Alia Atlas
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Alia Atlas
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Tony Przygienda
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Greg Shepherd
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Tony Przygienda
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Tony Przygienda
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… IJsbrand Wijnands
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… IJsbrand Wijnands
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Peter Psenak
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Peter Psenak
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Acee Lindem (acee)
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Tony Przygienda
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Acee Lindem (acee)
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… IJsbrand Wijnands
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Les Ginsberg (ginsberg)
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Tony Przygienda
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… IJsbrand Wijnands
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Les Ginsberg (ginsberg)
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… IJsbrand Wijnands
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Les Ginsberg (ginsberg)
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Tony Przygienda
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Peter Psenak
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… IJsbrand Wijnands
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Acee Lindem (acee)
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Eric C Rosen
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Tony Przygienda
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Les Ginsberg (ginsberg)
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Tony Przygienda
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Les Ginsberg (ginsberg)
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Tony Przygienda
- Re: [Isis-wg] [Bier] WGLC: draft-ietf-bier-isis-e… Xiejingrong