Troubleshooting guide

3. Troubleshooting Functional Failures During Operation
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Table 3-27: Items to check for first-hop-router
3.9.2 Multicast data is forwarded twice in the IPv4 PIM-SM network
If multicast data is forwarded twice in an IPv4 PIM-SM network configuration, check the settings
of each router and if multiple routers exist in one network, modify the settings so that PIM-SM runs
on the interface in the network.
The following table shows the items to check when data continues to be forwarded twice even after
you have checked and modified the settings as described above.
Table 3-28: Items to check when data continues to be forwarded twice
3.9.3 Communication is not possible on the IPv4 PIM-SSM networks
If multicast forwarding is not possible in an IPv4 PIM-SSM network configuration, isolate the
cause of the problem according to the failure analysis method described below.
The following figure shows an example of an IPv4 PIM-SSM network.
Figure 3-11: Example of an IPv4 PIM-SSM network
No. Items to check and commands Action
1 Make sure that the Switch is directly connected to the
multicast sender.
If the Switch is not connected directly, check the
network configuration.
2 Make sure that PIM-SM or IGMP is running on the
interface connected to the multicast sender.
show ip pim interface
show ip igmp interface
If PIM-SM or IGMP is not running, check and modify
the configuration so that PIM-SM or IGMP runs on the
interface.
3 Check whether multicast routing information exists.
show ip mroute
If multicast routing information does not exist, make
sure that the multicast data source address is the
network address of the interface directly connected to
the multicast sender.
No. Items to check and commands Action
1 Check the PIM neighboring information of the
interface belonging to the network with multiple
routers.
show ip pim neighbor
If neighboring routers are not displayed, check the
following:
• Use the
show ip pim interface command to
make sure that PIM-SM is running on the interface
connected with the neighboring routers.
• Make sure that the configuration does not contain
filtering or other settings that suppress forwarding
of protocol packets. For details about the
procedure for checking the filter configuration
information, see 3.25.1 Checking the filters and
QoS configuration information.
• Check the settings of the neighboring routers.