Thank you very much Oli > it will send a join after a new RPF intf. has been identified for a given source. I see, so if I'll run IP FRR/LFA it will be almost immediately right please?
>IIRC, there is/was some interdependency with pim query-interval and link-up I see, so I'll definitely need to make sure my IGP adjacency to come up before the PIM neighborship is established on a given link I don't really see any advantage in tuning the PIM query-interval(which affects hellos) on the p2p links between routers because when the link goes down the PIM neighbor is removed immediately I guess the longest delay is introduced when the links at router connected to source fails -as the routing change needs to be propagated via IGP -than it all boils down to how well is the IGP tuned for fast convergence adam -----Original Message----- From: Oliver Boehmer (oboehmer) [mailto:[email protected]] Sent: Monday, June 25, 2012 11:32 AM To: adam vitkovsky; [email protected] Subject: RE: [c-nsp] fast multicast convergence > Consider this PIM-SM scenario > > Designated Router has two paths towards the Source and RPF has chosen > one > > The m-cast traffic will flow via the RPF interface down to the > interested receivers as long as the DR will be sending the periodic > Join messages up the Source-Tree > > Now when the RPF interface goes down and after the IGP converges > > -will the DR send triggered Join message via the new RPF interface > towards the Source immediately after it learns the alternate path > towards the Source please? > > -or the DR will simply wait till the next scheduled Join period please? it will send a join after a new RPF intf. has been identified for a given source. In earlier IOS releases, there was a backoff after the first change in the RIB, RPF process started 500 msec after first change in the RIB and went through all S,G/*,G to update RPF intf. Now this is event-driven. > I'm asking because the PIM-SM convergence is based on how fast can be > the Join message propagated from the DR to Source over the backup path > -creating the SPT state in all routers it passes through > > In MoFRR this is preprogramed by DR sending Join also via the Backup > path (in XR it also enables triggered Joins) true. > I don't see any specific knob to control the pace at which the > periodic join msgs are sent you can configure the RPF backoff mentioned earlier (ip multicast rpf backoff). > Or would also this be affected by the query-interval please? IIRC, there is/was some interdependency with pim query-interval and link-up to avoid a blackhole between IGP coming up and PIM establishing a neighbourship.. possibly something to check in your specific environment.. oli _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
