[Xorp-users] Multicast problem

[Pavlin Radoslavov]

Ben Greear <greearb at candelatech.com> wrote:

> > However, if the RP sends source-specific (S,G) toward the DR, then
> > the multicast data packets will be forwarded natively (without the
> > PIM Register encapsulation overhead).
> > In XORP you can control when the RP sends the DR by using the
> > following configuration inside the pimsm4 or pimsm6 block:
> >
> >         switch-to-spt-threshold {
> >             /* approx. 1K bytes/s (10Kbps) threshold */
> >             disable: false
> >             interval: 100
> >             bytes: 102400
> >         }
> >
> > If you set "bytes" to 0 for example, then the RP should send the
> > (S,G) Join right after the first PIM Register for that socket is
> > received by the RP. In your case where performance is critical
> > you might want to set "bytes" to 0.
> >   
> What is the benefit of setting it to something larger than 0 ?

If the sender's data traffic is very low bandwidth for
example. E.g., if the sender transmits a packet every few minutes,
the (S,G) control overhead (the periodic Join messages, routing
and forwarding entries) is too much.

Pavlin