[c-nsp] fast multicast convergence

[adam vitkovsky]

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?

 

 

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)

 

I don't see any specific knob to control the pace at which the periodic join
msgs are sent 

Or would also this be affected by the query-interval please? 

 

Thank you

 

adam