Peter,
Pls see inline. Rgds Shraddha -----Original Message----- From: Peter Psenak [mailto:ppse...@cisco.com] Sent: Monday, December 29, 2014 2:02 PM To: Shraddha Hegde; draft-ietf-ospf-segment-routing-extensi...@tools.ietf.org; draft-ietf-isis-segment-routing-extensi...@tools.ietf.org Cc: ospf@ietf.org; isis...@ietf.org Subject: Re: [Isis-wg] Mail regarding draft-ietf-ospf-segment-routing-extensions Shraddha, I do not see how an originator can set any flag regarding the protection of the locally attached prefix. <Shraddha> The originator advertises 2 node-sids. One with p flag set and the other without the p-flag set. It's all the routers on the path towards such prefix that need to deal with the protection. <Shraddha> The receiving nodes will download protected path for the node-sid with p-flag set and download Unprotected path for the node-sid with p-flag unset. Signaling anything from the originator seems useless. <Shraddha> For node-sids it's the others who need to build the forwarding plane but it's only the originator who can signal which of Sid need to be built with protection and which not. Other routers on the path cannot signal this information. With this you have two paths for the node. One is protected and the other is unprotected. This meets the requirement of having an un-protected path. It's very much in parallel to B-flag in adj-sids. It is similar to advertising multiple adj-sids one with B-flag on and other with b-flag off , to get protected and unprotected Adj-sids. thanks, Peter On 12/29/14 09:26 , Shraddha Hegde wrote: > Yes.You are right. > > Lets say a prefix sid has a flag "p flag". If this is on it means build a > path and provide protection. > If this is off it means build a path with no protection. > The receivers of the prefix-sid will build forwarding plane based on this > flag. > > The applications building the paths will either use prefix-sids with p flag > on or off based on the need of the service. > Rgds > Shraddha > > > -----Original Message----- > From: Peter Psenak [mailto:ppse...@cisco.com] > Sent: Monday, December 29, 2014 1:49 PM > To: Shraddha Hegde; > draft-ietf-ospf-segment-routing-extensi...@tools.ietf.org; > draft-ietf-isis-segment-routing-extensi...@tools.ietf.org > Cc: ospf@ietf.org; isis...@ietf.org > Subject: Re: [Isis-wg] Mail regarding > draft-ietf-ospf-segment-routing-extensions > > Shraddha, > > the problem is that the node that is advertising the node-sid can not > advertise any data regarding the protection of such prefix, because the > prefix is locally attached. > > thanks, > Peter > > On 12/29/14 09:15 , Shraddha Hegde wrote: >> Peter, >> >> If there is a service which has to use un-protected path and while >> building such a path if the node-sids Need to be used (one reason >> could be label stack compression) , then there has to be unprotected >> node-sid that this service can make use of. >> >> Prefix -sids could also be used to represent different service >> endpoints which makes it even more relevant to have A means of representing >> unprotected paths. >> >> Would be good to hear from others on this, especially operators. >> >> Rgds >> Shraddha >> >> >> -----Original Message----- >> From: Peter Psenak [mailto:ppse...@cisco.com] >> Sent: Monday, December 29, 2014 1:35 PM >> To: Shraddha Hegde; >> draft-ietf-ospf-segment-routing-extensi...@tools.ietf.org; >> draft-ietf-isis-segment-routing-extensi...@tools.ietf.org >> Cc: ospf@ietf.org; isis...@ietf.org >> Subject: Re: [Isis-wg] Mail regarding >> draft-ietf-ospf-segment-routing-extensions >> >> Shraddha, >> >> node-SID is advertised by the router for the prefix that is directly >> attached to it. Protection for such local prefix does not mean much. >> >> thanks, >> Peter >> >> On 12/24/14 11:57 , Shraddha Hegde wrote: >>> Authors, >>> We have a "backup flag" in adjacency sid to indicate whether the >>> label is protected or not. >>> Similarly. I think we need a flag in prefix-sid as well to indicate >>> whether the node-sid is to be protected or not. >>> Any thoughts on this? >>> Rgds >>> Shraddha >>> >>> >>> _______________________________________________ >>> Isis-wg mailing list >>> isis...@ietf.org >>> https://www.ietf.org/mailman/listinfo/isis-wg >>> >> >> . >> > > . > _______________________________________________ OSPF mailing list OSPF@ietf.org https://www.ietf.org/mailman/listinfo/ospf
