ok, we in sync then ... thanks
-- tony On Sat, Jun 25, 2022 at 8:07 AM Ketan Talaulikar <ketant.i...@gmail.com> wrote: > Hi Tony, > > Just allowing sub-TLVs for the BGP-LS ISIS Flood Reflection TLV will > address my concerns for this draft. For the rest, new TLVs/sub-TLVs can be > introduced on a need basis down the line. > > Thanks, > Ketan > > > On Fri, Jun 24, 2022 at 11:43 PM Tony Przygienda <tonysi...@gmail.com> > wrote: > >> >> >> On Fri, Jun 24, 2022 at 6:43 PM Ketan Talaulikar <ketant.i...@gmail.com> >> wrote: >> >>> Hi Tony, >>> >>> Please check inline below. >>> >>> On Wed, Jun 22, 2022 at 9:41 PM Tony Przygienda <tonysi...@gmail.com> >>> wrote: >>> >>>> hey Ketan, since as you know ;-) BGP-LS is not really IGP 1:1 >>>> translation we try to put into BGP-LS here only the stuff that is strictly >>>> needed for topology discovery and understanding for advanced computation >>>> and nothing else. >>>> >>> >>> KT> I don't agree with the "nothing else". At least I can't claim to >>> have the full knowledge of all the solutions being designed and deployed >>> using BGP-LS. >>> >> >> I can't answer to that except BGP-LS doesn't have enough information as >> it stands to do a lot of stuff that you can do using full IGP database. And >> I try to define a minimum set of what is useful already. We can always add >> more stuff later but maybe we cannot given what we defined and I miss your >> point (which seems to be the case reading rest of your email). >> >> >>> >>> >>>> And hence, since the 1:1 TLV correspondence is nowhere to be seen by >>>> now if you look at ospf/isis encoding and what BGP-LS formats are today >>>> your requirements are interesting but I'm not sure where they came from. >>>> >>> >>> KT> Not everything from OSPF/ISIS is in BGP-LS, but whatever we've put >>> follows closely the semantics and encoding (with due consideration for >>> normalization across the IGPs). So I don't support the design of BGP-LS >>> encodings that are different from the underlying IGPs without strong >>> justification. >>> >> >> well, no, it doesn't. if you look e.g. at MT encoding it's upside down >> compared to ISIS encoding. it's encoded within link descriptor while in >> ISIS it's its own TLV with MT being on top. BGP-LS encoding is nothing like >> the original ISIS encoding in most parts e.g. by already cumulating lots >> stuff into same descriptior which in ISIS can be spread across multiple >> TLVs and fragments. >> >> Unless you point me to a normative reference where it says that BGP-LS is >> following IGP encoding closely I take it just as an assertion you make and >> we disagree, Ketan. >> >> >>> >>> >>>> >>>> >>>> The flag indicates already whether something is client or reflector on >>>> an adjacency. cluster ID is there as well to differentiate between >>>> different clusters. L2 C/FR adjacencies will show up as well. good enough >>>> to understand topology and compute AFAIS. All this is achievable by >>>> putting this element on the link TLV (the draft should explain it better, >>>> it just grabs codepoints in node/link/prefix & e'thing else ;-). Yes, we >>>> could annotate just the node assuming strict adherence to the IGP draft >>>> today but putting the element on the link descriptor follows the IGP spec >>>> itself and will allow to break the RFC if necessary later also in BGP-LS >>>> (by e.g. allowing a node to be client of two different clusters or even a >>>> node being reflector for 2 different clusters. Observe that this will not >>>> work in case of auto-discoery since that's on node caps ;-) But those are >>>> sutble discussions that need to be documented into the BGP-LS draft as >>>> procedures once adopted. >>>> >>> >>> KT> So you see the scope for adding some more of the sub-TLVs from the >>> ISIS flood-reflection draft into this BGP-LS document? If so, great - we >>> can always extend on a need basis. >>> >> >> agreed >> >> >>> >>> >>>> Those discussions are natural and necessary since BGP-LS is NOT IGP >>>> database but a distorted, simplified view for topology discovery. Or at >>>> least that's how it's used in reality based on the shortcomings of its >>>> design ;-) >>>> >>>> As I explained, unless L1 adjacencies are being formed IMO they don't >>>> belong into BGP-LS FR information, otherwise will show up in BGP-LS >>>> naturally. Neither does IMO auto-discovery of FR. >>>> >>>> As to mismatch of e.g. cluster ID/role. good observation but we don't >>>> send IIHs in BGP-LS either to discover MTU mismatch so I don't see that's >>>> what BGP-LS is here for >>>> >>> >>> KT> The main sticking point for me here is that you have not allowed for >>> the BGP-LS Flood Reflection TLV to have support for sub-TLVs as is the >>> case with its underlying ISIS Flood Reflection TLV. It is a very minor >>> thing that can be easily fixed and I am unable to understand why this >>> cannot or should not be done. Anyway, I rest my case :-) >>> >> >> ah. ok. if that's your only thing, sure. we can allow for sub-TLVs. >> suggest encoding change or Jordan can make it so sub-TLVs can be plugged in >> later >> >> thanks for the comments and careful read >> >> -- tony >> >> >>> >>> Thanks, >>> Ketan >>> >>> >>>> >>>> -- tony >>>> >>>> On Wed, Jun 22, 2022 at 4:44 PM Ketan Talaulikar <ketant.i...@gmail.com> >>>> wrote: >>>> >>>>> Hi Tony, >>>>> >>>>> I may not be the best judge, for this feature, of which of the ISIS >>>>> sub-TLV need to get into BGP-LS and which do not. In my limited >>>>> understanding of the feature and its deployment, the other 3 sub-TLVs >>>>> would >>>>> be equally useful to get into BGP-LS. Isn't the Flood Reflection >>>>> Adjacency Sub-TLV the one that distinguishes a "normal" ISIS >>>>> adjacency from a reflector adjacency formed over the tunnel? Isn't it >>>>> useful to know what sort of tunnel encapsulation is being signaled so a >>>>> discrepancy between the two ends can be detected? >>>>> >>>>> I am copying LSR WG which probably is the better group than IDR to >>>>> review and comment on this. >>>>> >>>>> In any case, I am ok to go ahead and skip the inclusion of certain >>>>> ISIS sub-TLVs in BGP-LS - they can be always added later on. >>>>> >>>>> But I am not ok that while the ISIS Flood Reflection TLV has support >>>>> for sub-TLVs, its corresponding BGP-LS ISIS Flood Reflection TLV does not >>>>> allow for sub-TLVs. The encoding needs to be consistent. That is a >>>>> show-stopper in my opinion. >>>>> >>>>> Thanks, >>>>> Ketan >>>>> >>>>> >>>>> On Wed, Jun 22, 2022 at 7:29 PM Tony Przygienda <tonysi...@gmail.com> >>>>> wrote: >>>>> >>>>>> Ketan, AFAIS tunnel status is not part of IGP state and should be >>>>>> derived from alternate mechanisms just like interface up/down state on >>>>>> the >>>>>> node. We don't carry interface up/down in BGP-LS today and should not >>>>>> (observe that I really mean admin/phy up/down and not IGP adj up/down >>>>>> here). And then, those L1 tunnels either form IGP adjacencies on them in >>>>>> which case you'll get them in BGP-LS as neighbors or they use something >>>>>> alternate like e.g. BFD (or nothing at all possibly) and at this point it >>>>>> will become really weird to carry in BGP-LS an L1 tunnel which does not >>>>>> have IGP adjacency on it ... >>>>>> >>>>>> open to suggestions but AFAIS the FR/client L2 adjacencies are in >>>>>> BGP-LS already per normal procedures (and the fact that you see >>>>>> client/reflector flag on both nodes & cluster ID allows you to derive the >>>>>> property of the adjacency) but the L1 mesh (if used) has no business in >>>>>> BGP-LS unless it forms IGP L1 adjacencies. >>>>>> >>>>>> -- tony >>>>>> >>>>>> On Wed, Jun 22, 2022 at 3:26 PM Ketan Talaulikar < >>>>>> ketant.i...@gmail.com> wrote: >>>>>> >>>>>>
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