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, then 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 router 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, then the router assumes it is the best path, and the specified multicast group traffic will flow
through the router.
RPT-tree
A
Yes
setting indicates the route is using the RPT. A
No
setting indicates the route is using the applicable
SPT.
Downstream interfaces
For each downstream interface the following information is shown:
VLAN
Lists the
vid
of the VLAN the router is using to send the outbound packets of the current multicast flow to the
next-hop router:
State
Indicates whether the outbound VLAN and next-hop router for the current multicast flow are receiving
datagrams.
Pruned
The router has not detected any joins from the current multicast flow and is not currently forwarding
datagrams in the current VLAN.
Forwarding
The router has received a join for the current multicast flow and is forwarding datagrams in the current VLAN.
Up Time (sec)
Indicates the elapsed time in seconds since the router learned the displayed information about the current
multicast flow.
Expire Time (sec)
Downstream interface entries for an mroute in PIM-SM are only created when those interfaces become joined
for the mroute's flow. Unless join state is periodically refreshed, a downstream interface will eventually move
from forwarding to pruned. When forwarding,
Expire Time
indicates when the router expects forwarding to
end unless another join for the flow is received. After moving to prune state, the downstream interface entry
will last for a short while longer, indicated by
Expire Time
, before being removed completely.
Route entry data for a specific multicast group
The neighbor field indicates that the router is receiving multicast traffic from a neighboring PIM router. A blank
neighbor field indicates that the multicast source is directly connected to the router instead of another PIM router.
switch(config)# show ip mroute 239.255.12.42 10.0.0.10
IP Multicast Route Entry
Group Address : 239.255.12.42
Source Address : 10.0.0.10
Neighbor :
Chapter 4 PIM-SM (Sparse Mode)
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