--------------- ---- ------------------ ------------------
10.29.30.2 29 196 89
Syntax:
show ip pim [neighbor [
ip-address
]]
Lists the same information as the
show ip pim neighbor
Showing a specific neighbor
This example simulates output from routing switch “#1” in
Figure 9: Multicast network with a multinetted VLAN
on page 60. The data is from the first downstream neighbor (routing switch “#2”.)
switch(config)# show ip pim neighbor 10.29.30.2
PIM Neighbor
IP Address : 10.29.30.2
VLAN : 29
Up Time (sec) : 26
Expire Time (sec) : 79
PIM-DM
In a network where IP multicast traffic is transmitted for multimedia applications, traffic is blocked at routed
interface (VLAN) boundaries unless a multicast routing protocol is running. PIM is a family of routing protocols
that form multicast trees to forward traffic from multicast sources to subnets are using a protocol such as IGMP to
request the traffic. PIM relies on the unicast routing tables created by any of several unicast routing protocols to
identify the path back to a multicast source, known as reverse path forwarding (RPF.) Based on information
provided by the unicast routing tables, PIM sets up a distribution tree for the multicast traffic. The PIM-DM and
PIM-SM protocols on the switches enable and control multicast traffic routing.
IGMP provides the multicast traffic link between a host and a multicast router running PIM-DM or PIM-SM. IGMP
and either PIM-DM or PIM-SM must be enabled on VLANs whose member ports have directly connected hosts
with a valid need to join multicast groups. PIM-DM is used in networks where, at any given time, multicast group
members exist in relatively large numbers and are present in most subnets.
PIM-DM features
PIM-DM features on switches covered by this guide include:
Routing protocol support
PIM uses whichever unicast routing protocol is running on the routing switch. These can include:
• RIP
• OSPF
• Static routes
• Directly connected interfaces
VLAN interface support
The MRT supports up to 128 outbound VLANs at any given time. The sum of all outbound VLANs across all
current flows on a router may not exceed 128. (A single flow may span one inbound VLAN and up to 128
outbound VLANs, depending on the VLAN memberships of the hosts actively belonging to the flow.)
Chapter 3 PIM-DM (Dense Mode)
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