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3. Troubleshooting Functional Failures in Operation
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3.8 IPv4 Multicast Routing Communication Failure
Actions to be taken if IPv4 multicast communication failures occur on this system are described below.
3.8.1 Communication on IPv4 PIM-SM Network Is Disabled
If multicast relay is disabled in the IPv4 PIN-SM network configuration, isolate the cause according to the failure
analysis method below.
The figure below illustrates a network example of IPv4 PIM-SM.
Figure 3-11: Example of IPv4 PIM-SM Network
Note
• BSR: This router delivers rendezvous point information (for details, see the manual "Configuration Settings").
• Rendezvous point router: This router relays the packets, for which the relay destination is not determined, toward
the multicast receiver (for details, see the manual "Configuration Settings").
• first-hop-router: This router is directly connected to the multicast sender.
• last-hop-router: This router is directly connected to the multicast receiver.
(1) Common check items
The table below shows the common check items for all system in the IPv4 PIM-SM network configuration.
Table 3-22: Common Check Items
No. Troubleshooting Steps and Command Action
1 Confirm that the use of multicast function is designated (ip
multicast routing) in the configuration.
show running-config
If the use of multicast function is not designated, correct the
configuration.
2 Confirm that PIM is running on one or more interfaces.
show ip pim interface
If PIM is not running, check the configuration. Set PIM to run
on one or more interfaces. If the interface set in the
configuration to run PIM is not displayed by the show ip
pim interface command, confirm that multi-homing is
not set on the interface.
3 Check to see if IGMP snooping is applied to the interfaces
with PIM enabled.
show igmp-snooping
If IGMP snooping is applied, confirm the following:
• Confirm the port to which the neighboring router connected
is set as multicast router port of IGMP snooping.
• See "3.5.4 Multicast Relay by IGMP snooping Is
Disabled."
Multicast
Multicast
data
sender
BSR and rendezvous point
router
Multicast
receiver
Multicast
sender
Participation in
the IGMP group
Participation in
the IGMP group
first-hop-router
last-hop-router