Troubleshooting guide

3. Troubleshooting Functional Failures During Operation
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Table 3-54: Items to check when data continues to be forwarded twice
3.12.5 IPv6 multicast communication problems in VRF
If a problem on IPv6 multicast communication occurs in VRF, check the following.
Table 3-55: Items to check for VRF
3.12.6 IPv6 multicast communication problems in an extranet
To resolve problems on IPv6 multicast communication in an extranet, first, try to use the check
items described in 3.12.5 IPv6 multicast communication problems in VRF and make sure that
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
1 Check the port number and VLAN ID to make
sure that the interface for VRF is correct.
show ipv6 vrf
show vlan
show ipv6 pim interface
If the settings are not correct, modify the configuration or
connection.
2 If the Switch is used as the rendezvous point,
make sure that the Switch is operating as a
rendezvous point candidate on the target VRF.
show ipv6 pim vrf all rp-mapping
If the Switch is not operating as a rendezvous point candidate,
check whether the address of the loopback interface for the
target VRF is specified in the rendezvous point candidate
setting in the configuration.
show running-config
3 If the Switch is used as BSR, make sure that the
Switch is operating as a BSR candidate on the
target VRF.
show ipv6 pim vrf all bsr
If the Switch is not operating as a BSR candidate, check
whether the address of the loopback interface for the target
VRF is specified in the BSR candidate setting in the
configuration.
show running-config
4 If multiple VRFs are used, check whether a
global network or specific VRF occupies an
unexpectedly large number of multicast
forwarding entries.
show ipv6 mcache vrf all
If a global network or specific VRF occupies more multicast
forwarding entries than expected in the network design, check
whether any unexpected multicast forwarding entries are
created. If many negative caches are found, check whether
there is a terminal that is sending unnecessary packets.
Also, set the maximum number of forwarding entries for each
VRF to prevent a global network or specific VRF from
occupying forwarding entries.
Target configuration:
ipv6 pim vrf <vrf id> mcache-limit <number>
5 Check each VRF configuration by using the
check items in 3.12.1 Communication is not
possible on the IPv6 PIM-SM networks through
3.12.4 Multicast data is forwarded twice in the
IPv6 PIM-SSM network.
Specify the target VRF for each command to check the
information of the VRF. For details about specifying VRF, see
the manual Operation Command Reference.