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ExtremeWare Software 7.0.0 Command Reference Guide
IP Multicast Commands
PIM Dense Mode
Protocol Independent Multicast-Dense Mode (PIM-DM) is a multicast routing protocol that is similar to
DVMRP. PIM-DM routers perform reverse path multicasting (RPM). However, instead of exchanging its
own unicast route tables for the RPM algorithm, PIM-DM uses the existing unicast route table for the
reverse path. As a result, PIM-DM requires less system memory.
PIM-DM is a broadcast and prune protocol. Using PIM-DM, multicast routes are pruned and grafted in
the same way as DVMRP.
PIM Sparse Mode (PIM-SM)
Unlike PIM-DM, PIM-SM is an explicit join and prune protocol, and it supports shared trees as well as
shortest path trees (SPTs). The routers must explicitly join the group(s) in which they are interested in
becoming a member, which is beneficial for large networks that have group members who are sparsely
distributed.
Using PIM-SM, the router sends a join message to the rendezvous point (RP). The RP is a central
multicast router that is responsible for receiving and distributing multicast packets. By default, the RP is
selected dynamically. You can also define a static RP in your network, using the following command:
config pim crp static <rp address>
When a router has a multicast packet to distribute, it encapsulates the packet in a unicast message and
sends it to the RP. The RP decapsulates the multicast packet and distributes it among all member
routers.
When a router determines that the multicast rate from of a particular group from a particular
originating router (not the RP) has exceeded a configured threshold, that router can send an explicit join
to the originating router. When this occurs, the receiving router gets the multicast directly from the
sending router, and bypasses the RP.
NOTE
You can run either PIM-DM or PIM-SM per VLAN.
PIM Mode Interoperation
An Extreme Networks switch can function as a PIM multicast border router (PMBR). A PMBR
integrates PIM-SM and PIM-DM traffic.
When forwarding PIM-DM traffic into a PIM-SM network, the PMBR notifies the RP that the PIM-DM
network exists. The PMBR forwards PIM-DM multicast packets to the RP, which in turn forwards the
packets to those routers that have joined the multicast group.
The PMBR also forwards PIM-SM traffic to a PIM-DM network. The PMBR sends a join message to the
RP and the PMBR floods traffic from the RP into the PIM-DM network.
No commands are needed to enable PIM mode interoperation. PIM mode translation is automatically
enabled when a dense mode interface and a sparse mode interface are enabled on the same switch.
Summary of Contents for ExtremeWare 7.0.0
Page 88: ...88 ExtremeWare Software 7 0 0 Command Reference Guide Commands for Accessing the Switch ...
Page 276: ...276 ExtremeWare Software 7 0 0 Command Reference Guide FDB Commands ...
Page 324: ...324 ExtremeWare Software 7 0 0 Command Reference Guide QoS Commands ...
Page 342: ...342 ExtremeWare Software 7 0 0 Command Reference Guide NAT Commands ...
Page 502: ...502 ExtremeWare Software 7 0 0 Command Reference Guide SLB Commands ...
Page 680: ...680 ExtremeWare Software 7 0 0 Command Reference Guide Security Commands ...
Page 734: ...734 ExtremeWare Software 7 0 0 Command Reference Guide STP Commands ...
Page 772: ...772 ExtremeWare Software 7 0 0 Command Reference Guide ESRP Commands ...
Page 1226: ...1226 ExtremeWare Software 7 0 0 Command Reference Guide IPX Commands ...
Page 1242: ...1242 ExtremeWare Software 7 0 0 Command Reference Guide ARM Commands ...
Page 1320: ...1320 ExtremeWare Software 7 0 0 Command Reference Guide PoS Commands ...
Page 1430: ...1430 ExtremeWare Software 7 0 0 Command Reference Guide MPLS Commands ...