All things related to multicast

["Bogatinovski, M." <>]

Hello all,

I would like to discuss two issues (sorry if these have been already
discussed or are trivial).

First, what are the possibilities to interconnect a sparse mode domain (e.g
PIM-SM) with a dense, flood and prune domain (e.g. PIM-DM or DVMRP):
1) The border router (BR) in PIM-SM domain is a wild-card receiver (*, *,
RP) and receives the traffic from RPs for all groupes, and forwards it to
the BR in DM domain. In the reverse direction, the BR in SM domain will
encapsulate the traffic received from the dense mode domain (or use SPT
trees) and sent to RPs.
2) All RPs reside in the BR in SM domain.
in both cases, is SPT traffic a problem that is treated in a different way?
Is it necessary for the dense mode domain to work with Domain Wide Reports
(in order to tell the membership to its BR)?

Second question is related to the flood and prune behavior of DVMRP and
PIM-DM. 
1) For DVMRP there is a periodic (~2 hours) ageing of prune state in the
routers, after which the next packet for that (S, G) pair is again flooded
to all leaf routers. 
2) For PIM-DM Prune information is also flushed periodically, which causes
multicast datagrams to be flooded again. The Prune holdtime has a default
value of 210 seconds.
Why there is so big discrepancy in the Prune-holdtime timers between DVMRP
and PIM-DM? It seems to me that PIM-DM performs worse than DVMRP regarding
the amount and frequency of flooding.

Thank you for your time,
Marjan.