Brocade Multi-Service IronWare Multicast Configuration Guide (Supporting R05.6.00) - Manual (Page 20)

8 Multi-Service IronWare Multicast Configuration Guide
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Mtrace overview
1
To define an IGMP (V1 and V2) membership time of 240 seconds, enter the following.
Brocade(config)# ip igmp group-membership-time 240
Syntax: [no] ip igmp group-membership-time num
The num variable specifies the number of seconds and can be a value from 5 - 26000.
The default value is 260.
Modifying IGMP (V1 and V2) maximum response time
Maximum response time defines how long the Brocade device will wait for an IGMP (V1 and V2)
response from an interface before concluding that the group member on that interface is down and
removing the interface from the group. Possible values are 1 – 25. The default is 10.
To change the IGMP (V1 and V2) maximum response time, enter a command such as the following
at the global CONFIG level of the CLI.
Brocade(config)# ip igmp max-response-time 8
Syntax: [no] ip igmp max-response-time num
The num variable specifies the number of seconds and can be a value from 1 – 25. The default is
10.
Security Enhancement for IGMP
A security enhancement has been made to IGMPv2 to adhere to the following recommendation of
RFC 2236: “Ignore the Report if you cannot identify the source address of the packet as belonging
to a subnet assigned to the interface on which the packet was received.”
NOTE
When used in applications such as IP-TV (or any multicast application in general), the administrator
should ensure that the set-top box (or multicast client) is configured on the same subnet as the v.e.
configured on the device. This is typically the case but is emphasized here to ensure correct
operation. Without this configuration, IGMP messages received by the device are ignored which
causes an interruption in any multicast traffic directed towards the set-top box (multicast client).
Mtrace overview
“mtrace” is a diagnostic tool to trace the multicast path from a specified source to a destination for
a multicast group. It runs over IGMP protocol. Mtrace uses any information available to it to
determine a previous hop to forward the trace towards the source.
There are three main components in an mtrace implementation. They are mtrace query, mtrace
request, and mtrace response.
The unicast "traceroute" program allows the tracing of a path from one machine to another. The
key mechanism for unicast traceroute is the ICMP TTL exceeded message, which is specifically
excluded as a response to multicast packets. The multicast traceroute facility allows the tracing of
an IP multicast routing path. Multicast traceroute also requires special implementations on the
part of routers.