Troubleshooting guide

3. Troubleshooting Functional Failures During Operation
85
Figure 3-12: Example of an IPv4 PIM-DM network
Notes:
•
first-hop-router: The router that is connected directly to the multicast sender
•
last-hop-router: The router that is connected directly to the multicast receivers
(1) Items checked in common
The following table shows the items checked in common for all the Switches in an IPv4 PIM-DM
network configuration.
Table 3-35: Items checked in common
No. Items to check and commands Action
1 Make sure that the setting for using the multicast
functionality (
ip multicast routing) exists in the
configuration.
show running-config
If the setting for using the multicast functionality does
not exist, modify the configuration.
2 Make sure that PIM-DM is specified (ip multicast
protocol pim-dm
) for the multicast protocol used in
the configuration.
show running-config
If PIM-DM is not specified for the multicast protocol,
modify the configuration.
3 Make sure that PIM-DM is running on one or more
interfaces.
show ip pim interface
If PIM is not running, check and modify the
configuration so that PIM runs on at least one of the
interfaces. If the configuration contains the setting for
running PIM-DM on an interface, but the interface is
not displayed by the
show ip pim interface
command, make sure that multihoming is not set for
the target interface.
4 Check whether IGMP snooping is set for the interface
on which PIM runs.
show igmp-snooping
If IGMP snooping is set, check the following:
Check whether the multicast router port for IGMP
snooping is set for the port connected to the
neighboring router.
• See 3.6.4 Multicast forwarding by IGMP
snooping is not possible.
5 Make sure that the configuration does not contain
filtering or other settings that suppress forwarding of
protocol packets and multicast packets on the interface
on which PIM and IGMP run.
show running-config
If the configuration contains a setting that suppresses
forwarding of protocol packets and multicast packets,
modify the configuration. For details about the
procedure for checking the filter configuration
information, see 3.25.1 Checking the filters and QoS
configuration information.