Troubleshooting guide

3. Troubleshooting Functional Failures During Operation
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3.12.2 Multicast data is forwarded twice in the IPv6 PIM-SM network
If multicast data is forwarded twice in an IPv6 PIM-SM network configuration, check the settings
of each router and if multiple routers exist in one network, modify the settings so that PIM 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 3-50: Items to check when data continues to be forwarded twice
3.12.3 Communication is not possible on the IPv6 PIM-SSM networks
If multicast forwarding is not possible in an IPv6 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 IPv6 PIM-SSM network.
Figure 3-18: Example of an IPv6 PIM-SSM 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 IPv6 PIM-SSM
3 Check whether multicast routing information exists.
show ipv6 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 ipv6 pim neighbor
If neighboring routers are not displayed, check the
following:
• Use the
show ipv6 pim command with the
interface parameter to make sure that PIM 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.
No. Items to check and commands Action