Protocol-Independent Multicast (Pim); Protocol-Independent Multicast - Dense Mode (Pim-Dm) - D-Link DES-3326 User Manual

24-port NWay Ethernet Switch User's Guide
messages sent from that source. If there are more than one
router on the subnet work with the same distance from the
source, the router with the lowest IP address is elected. DVMRP
supports tunnel interfaces (i.e. interfaces connecting two
multicast routers through one or more multicast-unaware
routers). More specifically, each tunnel interface should be
explicitly configured with the IP address of the local router' s
tunnel interface and the IP address of the remote router
interface. The scope of an IP multicast can be limited by using
the TTL field in the IP header. The following table lists the
conventional TTL values used to limit the scope of multicast
packets.

Protocol-Independent Multicast (PIM)

PIM contains two protocols: PIM – Dense Mode (PIM-DM) which
is more efficient when the group members are densely
distributed, and PIM – Sparse Mode (PIM-SM) which performs
better in cases where the group members are sparsely
distributed. Although these two algorithms belong to PIM and
they share similar control messages, they are essentially two
different protocols. Only PIM-DM is implemented on the DES-
3326.
Protocol-Independent Multicast – Dense
Mode (PIM-DM)
PIM-DM is similar to DVMRP and uses the RPM algorithm for
forming delivery trees, with some major differences. PIM-DM
requires the presence of a unicast routing protocol for finding
routes back to the source node, PIM-DM is independent of the
mechanisms employed by any specific unicast routing protocol.
This is different from the DVMRP and MOSPF protocols.
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