Brocade TurboIron 24X Series Configuration Guide - Manual (Page 829)

Brocade TurboIron 24X Series Configuration Guide 795
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Changing global IP multicast parameters
• 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.
Changing global IP multicast parameters
The following configurable parameters apply to PIM-DM and PIM-SM:
• Maximum number of PIM – You can change the maximum number of groups of each type for
which the software will allocate memory. By default, Layer 3 Switches support up to 1024 PIM
groups.
• Internet Group Membership Protocol (IGMP) V1 and V2 parameters – You can change the
query interval, group membership time, and maximum response time.
• Hardware forwarding of fragmented IP multicast packets – You can enable the Layer 3 Switch
to forward all fragments of fragmented IP multicast packets in hardware.
Changing dynamic memory allocation for IP multicast groups
Layer 3 Switches support up to 1024 PIM groups by default. Memory for the groups is allocated
dynamically as needed. For each protocol, previous releases support a maximum of 255 groups
and 255 IGMP memberships.
The software allocates memory globally for each group, and also allocates memory separately for
each interface IGMP membership in a multicast group. An interface becomes a member of a
multicast group when the interface receives an IGMP group membership report. For example, if the
Layer 3 Switch learns about one multicast group, global memory for one group is used. In addition,
if three interfaces on the device receive IGMP group membership reports for the group, interface
memory for three IGMP memberships also is used.
Since the same group can use multiple allocations of memory (one for the group itself and one for
each interface membership in the group), you can increase the maximum number of IGMP
memberships, up to 8192.
NOTE
The total for IGMP memberships applies to the device, not to individual interfaces. You can have up
to 8192 IGMP memberships on all the individual interfaces, not up to 8192 IGMP memberships on
each interface.