All things related to multicast

[John Zwiebel <>]

Since the NULL register is only processed far enough to update the
keepalive timer for the (S,G) on the PIM-RP, there's no need to worry
about the TTL.  The packet is empty so shouldn't be forwarded anywhere.

If one were to put something about this in the spec, I imagine it
would say something like: set to zero on sending ignore on receipt.

On Monday, May 19, 2003, at 09:35 AM, Charles R. Anderson wrote:

> On Thu, May 15, 2003 at 07:46:40PM -0700, Tom Pusateri wrote:
> pusateri> We zero the dummy ip header and only fill in the source and 
> group address.
> pusateri> This means the protocol type is 0 and there is no transport 
> header.
>
> Thanks.  What about the TTL of the encapsulated Null packet? Is that
> expected to be decremented once/twice like regular Register 
> encapsulated
> packets?  Do you set the TTL to zero, or something else?
>
> The pim draft isn't clear on these aspects.
>
> Thanks.
>
> --
> Charles R. Anderson
> Network Engineer
> Computing and Communications Center
> Worcester Polytechnic Institute