246 CHAPTER 7: U SING MULTICAST PROTOCOL COMMANDSmtracert Syntaxmtracert{ source-address } [ last-hop-address ] [ group-address ]ViewAny viewParametersource-address: Address of the multicast source.last-hop-address: Unicast address, which is the starting address of path tracing.This address must be an interface address of a hop router. By default, it is aphysical interface address of the local router.group-address: Address of multicast group. By default, the value is 0.0.0.0.DescriptionUsing the mtracert command, you can trace the network path from the multicastsource to the destination receiver along Multicast Distribution Tree, according toeither the multicast kernel routing table or RPF rule to the source. This commandcan help to locate the faults, such as information loss and configuration error.The trace mode to the group address of 0.0.0.0 is called weak trace mode.ExampleTrace the path reversely from the local hop router 18.110.0.1 to the multicastsource 10.10.1.2 in weak trace mode.mtracert 10.10.1.2Type Ctrl+C to abortMtrace from 10.10.1.2 to 18.110.0.1 via RPFQuerying full reverse path...-1 18.110.0.1Incoming Interface Address: 18.110.0.1Previous-Hop Router Address: 18.110.0.2Input packet count on incoming interface: 0Output packet count on outgoing interface: 0Total number of packets for this source-group pair: 0Protocol: PIMForwarding TTL: 0Forwarding Code: No error-2 18.110.0.2Incoming Interface Address: 11.110.0.2Previous-Hop Router Address: 11.110.0.4Input packet count on incoming interface: 0Output packet count on outgoing interface: 0Total number of packets for this source-group pair: 0Protocol: PIMForwarding TTL: 0Forwarding Code: No error-3 11.110.0.4Incoming Interface Address: 10.10.1.3Previous-Hop Router Address: 0.0.0.0Input packet count on incoming interface: 0
