Troubleshooting Multicast Stub Routing And Igmp; Strategies And Tools - HP ProCurve Secure Router 7203 dl Advanced Management And Configuration Manual

Configuring Multicast Support for a Stub Network

Troubleshooting Multicast Stub Routing and IGMP

Troubleshooting Multicast Stub Routing
and IGMP
This section gives strategies for troubleshooting multicast support on the stub
router only. If you determine that a problem originates on one of the remote
routers running the multicast routing protocol, then you must troubleshoot
that router and protocol. (See Chapter 11: Configuring Multicast Support
with PIM-SM.)
This section also describes how to troubleshoot IGMP, which is used both by
routers that run PIM-SM and those that run IGMP proxy.

Strategies and Tools

When hosts are not receiving multicast messages as they should, you need to
ascertain where the multicast messages are being lost.
Is the router receiving messages, but not forwarding them? In this case, the
router may not believe that the group exists on a network on which it does
exist, and IGMP functions might be at fault.
Is the router not receiving multicast messages at all? In this case, IGMP proxy
may be to blame; the helper device is not receiving reports from the router
telling it to send those multicast messages.
If you cannot locate the problem on the local router, you should, if possible,
troubleshoot the next-hop upstream router. See Chapter 11: Configuring
Multicast Support with PIM-SM for tips on troubleshooting PIM-SM.
When troubleshooting multicast stub routing, you should follow the general
procedure described below. You will use the show and debug commands
summarized in Table 10-2.
N o t e
You enter show and debug commands from the enable mode context. You
can also add do to the commands to enter them from any configuration mode
context.
10-19