sorry. What I meant is that if you restrict the number of ecmp path you have computed, it is not what the definition of strict-spf is.
IOW, strict-spf means that you forward according to what SPF algorithm has computed without applying any sort of constraint/policy/hack. s. > On Sep 19, 2016, at 12:17 PM, Alexander Vainshtein > <alexander.vainsht...@ecitele.com> wrote: > > Stefano, Chris and all, > I have to admit that I am completely confused: > - to the best of my understanding, Chris has asked whether a policy > that puts a limit on max. number of ECMP next hops is not compatible with the > Strict SPF algorithm > - Stefano says that "Yes, this policy is a good example when Strict SPF > algorithm can be advertised". > > > What do I miss? > Regards, > Sasha > > Office: +972-39266302 > Cell: +972-549266302 > Email: alexander.vainsht...@ecitele.com > > -----Original Message----- > From: spring [mailto:spring-boun...@ietf.org] On Behalf Of Stefano Previdi > (sprevidi) > Sent: Monday, September 19, 2016 12:43 PM > To: Chris Bowers <cbow...@juniper.net> > Cc: spring@ietf.org > Subject: Re: [spring] meaning of "Strict Shortest Path" algorithm in > draft-ietf-spring-segment-routing-09 > > >> On Sep 14, 2016, at 7:06 PM, Chris Bowers <cbow...@juniper.net> wrote: >> >> SPRING WG, >> >> The current text in draft-ietf-spring-segment-routing-09 regarding the >> "Strict Shortest Path" algorithm reads as follows. >> >> o "Strict Shortest Path": This algorithm mandates that the packet is >> forwarded according to ECMP-aware SPF algorithm and instruct any >> router in the path to ignore any possible local policy overriding >> SPF decision. The SID advertised with "Strict Shortest Path" >> algorithm ensures that the path the packet is going to take is the >> expected, and not altered, SPF path. >> >> One example of a local policy that overrides the ECMP-aware SPF >> algorithm decision is a limit on the number of ECMP next-hops. The >> text above implies that if a router places any limit on the number of >> ECMP forwarding next-hops then it would be wrong for it to advertise the >> “Strict Shortest Path” algorithm capability. >> >> Is this the intended interpretation? > > > well, yes. Your example is a good one for the “strict-SPF” behavior. > > s. > > >> >> If not, what is the intended interpretation? >> >> Thanks, >> Chris >> >> _______________________________________________ >> spring mailing list >> spring@ietf.org >> https://www.ietf.org/mailman/listinfo/spring > > _______________________________________________ > spring mailing list > spring@ietf.org > https://www.ietf.org/mailman/listinfo/spring _______________________________________________ spring mailing list spring@ietf.org https://www.ietf.org/mailman/listinfo/spring
