Hi Les, > On Jul 14, 2026, at 6:16 PM, Les Ginsberg (ginsberg) <[email protected]> > wrote: > > Acee - > > Please see inline. > >> -----Original Message----- >> From: Acee Lindem <[email protected]> >> Sent: Tuesday, July 14, 2026 1:15 PM >> To: Les Ginsberg (ginsberg) <[email protected]> >> Cc: lsr <[email protected]>; draft-admnr-lsr-igp-measurement- >> [email protected] >> Subject: Re: Questions on draft-admnr-lsr-igp-measurement-group-02 >> >> Hi Les, >> >>> On Jul 14, 2026, at 3:41 PM, Les Ginsberg (ginsberg) <[email protected]> >> wrote: >>> >>> The latest version of the draft defines a modified form of the sub-TLV: >>> 0 1 2 3 >>> 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 >>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ >>> | Type | Length | Group ID | AMP Protocol | >>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ >>> | | >>> | IPv4 or IPv6 Host Address (4 or 16 octets) | >>> | | >>> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ >>> Several questions: >>> 1) Given the Router Capability TLV carries V4 Router ID/V6 Router ID – why >>> is >> an application specific address necessary – and how would it be chosen? >>> (I have asked this before but did not receive a substantive answer) >> >> Specification of the IP endpoint allows sessions with multiple endpoints on >> the >> router. >> We can discuss this requirement but using a different EP could be used to >> measure a different path. >> > > [LES:] You will need more than a different node address in order to measure a > specific path. If that is what you are after I think you need more > specification of how endpoint addresses are chosen. > Until you do, I am seeing it as redundant with the already advertised router > id that is carried in every Router Capability TLV.
Fair enough - we can discuss amongst the authors. I know that different EPs can, in fact, imply different data planes with different encapsulations and we may want to measure them independently. > >> >>> 2) You are now requiring an address per “group ID”. Why? And how would a >> group specific address be chosen? >> >> The Group ID allows AMP sessions amongst different disjoint groups of >> routers. >> If this isn't a requirement, all routers in the domain can share the same >> Group >> ID. > > [LES:] Understood. I am just saying the group ID is underspecified. More on > that below. Sure. > >> >> >> >>> 3) Section 4 states: >>> “Given that an IP endpoint may be used for multiple measurement groups >>> and AMP protocols, a router should only establish a single session of >>> a given protocol type between the same two pairs of IP endpoints >>> (independent of how many groups the endpoint participates in). “ >>> This would argue that the encoding of the sub-TLV should be a list of Group >> ID/AMP Protocol pairs so that unnecessary duplication is avoided. >> >> That encoding would be an option. However, this simply says that we don't >> want to establish multiple AMP sessions for the same protocol between the >> same two endpoints. >> If you have two groups (1 and 2), it is entirely possible that two routers >> (A and >> B) would participate in both groups, where the other routers in groups 1 and >> 2 >> are different. We wouldn't want multiple sessions between routers A and B. >> > [LES:] Understood. I am just asking that you be efficient in your encoding - > something IS-IS has always been attentive to. What if the primary use case is a single group? With a list of groups, you'd need explicit AF specification so really only save 1 octet per group with a list. > >>> 4) There is no discussion of what a group ID is nor how consistency in >> configuration between nodes is achieved. >> >> Is this a trick question? How is configuration consistency ever achieved if >> not >> incumbent on those doing the configuration? >> > [LES:] No - this isn’t a trick question. The group id simply isn’t specified. > What numbers are valid? Are certain values reserved? Do they relate to > anything in the associated protocol? > It might be as simple as saying "the group id is an arbitrary number from > 0-255" - but you haven't said anything. Fair enough, we can add a discussion. Thanks, Acee > > Les > >> Thanks, >> Acee >> >> >> >>> Thanx. >>> Les >> > _______________________________________________ Lsr mailing list -- [email protected] To unsubscribe send an email to [email protected]
