Multicast Terms; Changing Global Ip Multicast Parameters - Dell PowerConnect B-RX Configuration Manual

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Multicast terms

PIM and DVMRP are broadcast and pruning multicast protocols that deliver IP multicast datagrams.
The protocols employ reverse path lookup check and pruning to allow source-specific multicast
delivery trees to reach all group members. DVMRP and PIM build a different multicast tree for each
source and destination host group.
Both DVMRP and PIM can concurrently operate on different ports of a device. Also, the CAM can
hold up to 1535 IPv4 multicast entries.
NOTE
Each of the multicast protocols uses IGMP. IGMP is automatically enabled on an interface when you
configure PIM or DVMRP on an interface and is disabled on the interface if you disable PIM or
DVMRP on the interface.
The following are commonly used terms in discussing multicast-capable routers. These terms are
used throughout this chapter.
Multicast terms
The following are commonly used terms in discussing multicast-capable routers. These terms are
used throughout this chapter.
Node: Refers to a router or the BigIron RX.
Root Node: The node that initiates the tree building process. It is also the router that sends the
multicast packets down the multicast delivery tree.
Upstream: Represents the direction from which a router receives multicast data packets. An
upstream router is a node that sends multicast packets.
Downstream: Represents the direction to which a router forwards multicast data packets. A
downstream router is a node that receives multicast packets from upstream transmissions.
Group Presence: Means that a multicast group has been learned from one of the directly
connected interfaces. Members of the multicast group are present on the router.
Intermediate Nodes: Routers that are in the path between source routers and leaf routers.
Leaf Nodes: Routers that do not have any downstream routers.
Multicast Tree: A unique tree is built for each source group (S,G) pair. A multicast tree is comprised
of a root node and one or more nodes that are leaf or intermediate nodes.
NOTE
Multicast protocols can only be applied to 1 physical interface. You must create multiple VLANs with
individual untagged ports and ve's under which you configure PIM.

Changing global IP multicast parameters

The sections below apply to PIM-DM, PIM-SM, and DVMRP.
572 BigIron RX Series Configuration Guide
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