Viewing the PIM route entry information for the specified multicast group (flow)

Syntax:


show ip pim [mroute [multicast-group-address multicast-source-address]]

[Group Address]

Lists the specified multicast group address.

[Source Address]

Lists the specified multicast source address.

[Source Mask]

Lists the network mask for the multicast source address.

Metric

Indicates the path cost upstream to the multicast source. Used when multiple multicast routers contend to determine the best path to the multicast source. The lower the value, the better the path.

Metric Pref

Used when multiple multicast routers contend to determine the path to the multicast source. When this value differs between routers, PIM selects the router with the lowest value.

If Metric Pref is the same between contending multicast routers, PIM selects the router with the lowest Metric value to provide the path for the specified multicast traffic. (Different vendors assign differing values for this setting.)

Assert Timer

The time remaining until the routing switch ceases to wait for a response from another multicast router to negotiate the best path back to the multicast source. If this timer expires without a response from any contending multicast routers, the routing switch assumes it is the best path, and the specified multicast group traffic will flow through the routing switch.

Downstream Interfaces

[VLAN]

Lists the VID of the destination VLAN on the next-hop multicast router.

Prune Reason

Identifies the reason for pruning the flow to the indicated VLAN:

Prune: A neighbor multicast router has sent a prune request.
Assert: Another multicast router connected to the same VLAN has been elected to provide the path for the specified multicast group traffic.
Other: Used where the VLAN is in the pruned state for any reason other than the above two reasons (such as no neighbors exist and no directly connected hosts have done joins.)

Routing switch "#1" in Multicast network with a multinetted VLAN showing a multicast group from a directly connected source

switch(config)# show ip pim mroute 239.255.255.1 10.27.30.2
 PIM Route Entry
   Group Address    : 239.255.255.1
   Source Address   : 10.27.30.2
   Source Mask      : 255.255.255.0
   Metric           :3
   Metric Pref      :120
   Assert Timer     : 0
Downstream Interfaces
 VLAN Prune Reason
 ---- ------------
 28   prune