> there is no such thing. By far away ABR I mean ABR far away from failing PE connecting local are to the area 0. There can be number of P routers in between.
Let me provide you with an illustration: PE can be in Honolulu. ABR in Huston. All in one area. For me this ABR is far away from PE. On Thu, Jul 7, 2022 at 11:35 AM Peter Psenak <ppse...@cisco.com> wrote: > Robert, > > On 07/07/2022 11:25, Robert Raszuk wrote: > > Hi Peter, > > > > > Section 4: > > > > > > "The intent of UPA is to provide an event driven signal of the > > > transition of a destination from reachable to unreachable." > > > > That is too vague. > > it's all that is needed. > > > > > I am asking how you detect that transition on a far away ABR. > > there is no such thing. The detection is done based on the prefix > transition from reachable to unreachabile in a local area by local ABRs. > Remote ABRs just propagate the UPA. > > thanks, > Peter > > > > > For example, are you tracking flooding on all links to subject PE from > > all its neighbours and only when all of them remove that link from > > topology you signal PUA ? > > > > If so practically such trigger may be pretty slow and inconsistent as in > > real networks as links over which PEs are connected are often of a > > very different quality, coming from different carriers and may have for > > stability varying BFD timers. So here you would have to wait for the > > slowest link to be detected on the neighbouring P router as down. > > > > Thx, > > R. > > > > On Thu, Jul 7, 2022 at 10:16 AM Peter Psenak <ppse...@cisco.com > > <mailto:ppse...@cisco.com>> wrote: > > > > Robert, > > > > On 06/07/2022 15:07, Robert Raszuk wrote: > > > Hi Peter, > > > > > > Can you please point me in the draft > > > > > > https://www.ietf.org/id/draft-ppsenak-lsr-igp-ureach-prefix-announce-00.txt > > < > https://www.ietf.org/id/draft-ppsenak-lsr-igp-ureach-prefix-announce-00.txt > > > > > > > > > < > https://www.ietf.org/id/draft-ppsenak-lsr-igp-ureach-prefix-announce-00.txt > > < > https://www.ietf.org/id/draft-ppsenak-lsr-igp-ureach-prefix-announce-00.txt > >> > > > > > to some section which specifies based on exactly what network > > flooding > > > changes UPA will be generated by ABRs ? > > > > Section 4: > > > > "The intent of UPA is to provide an event driven signal of the > > transition of a destination from reachable to unreachable." > > > > > > I think such text is not an implementation detail, but it is > > critical > > > for mix vendor interoperability. > > > > > > Can UPA also be generated by P node(s) ? > > > > only if they are ABRs or ASBRs. > > > > > > > > > > Specifically I was looking to find some information on how do you > > > achieve assurance that UPA really needs to be generated when using > > > various vendor's nodes with very different flooding behaviours > > and when > > > subjects PEs may have a number of different links each with > > different > > > node/link down detection timer ? > > > > sorry, I don't understand the above. > > > > thanks, > > Peter > > > > > > > > Many thx, > > > R. > > > > > > >
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