Configuring IP Multicast Routing
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This tool can be used to verify connectivity among RPs or other multicast
routers.
Mtrace
Cisco also provides a multicast traceroute tool. The multicast version of trac-
eroute is somewhat different than the unicast version. The complete syntax
for mtrace is mtrace source [destination] [group]. The source is the
unicast IP address for the source of the multicast group. The destination
is used when following the forwarding path established by the source or
shared tree distribution toward a unicast destination. The group option is
used to establish the tree for the specified group. If no destination or group
options are specified, the mtrace will work from the incoming multicast
interfaces back toward the multicast source. Here are a few samples of the
command and its output:
RouterB#mtrace 198.32.163.74
Type escape sequence to abort.
Mtrace from 198.32.163.74 to 172.16.25.9 via RPF
From source (blaster.oregon-gigapop.net) to destination (?)
Querying full reverse path...
0 172.16.25.9
-1 172.16.25.9 PIM/MBGP [198.32.163.0/24]
-2 172.16.25.10 PIM/MBGP [198.32.163.0/24]
-3 ogig-den.oregon-gigapop.net (198.32.163.13) [AS 4600] PIM
[198.32.163.64/26]
-4 0car-0gw.oregon-gigapop.net (198.32.163.26) [AS 4600] PIM
[198.32.163.64/26]
-5 blaster.oregon-gigapop.net (198.32.163.74)
RouterB#
RouterB#mtrace 198.32.163.74 224.2.243.55
Type escape sequence to abort.
Mtrace from 198.32.163.74 to 172.16.25.9 via group
224.2.243.55
From source (blaster.oregon-gigapop.net) to destination (?)
Querying full reverse path...
0 172.16.25.9
-1 172.16.25.9 PIM/MBGP Reached RP/Core [198.32.163.0/24]
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