Troubleshooting guide

3. Troubleshooting Functional Failures During Operation
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Table 3-32: Items to check when data continues to be forwarded twice
3.9.5 IPv4 multicast communication problems in VRF
If a problem on IPv4 multicast communication occurs in VRF, check the following.
Table 3-33: Items to check for VRF
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 command with the
interface parameter 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.
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 ip vrf
show vlan
show ip pim interface
If the settings are not correct, modify the configuration
or connection.
2 For AX6700S, AX6600S, or AX6300S series switches,
make sure that the multicast protocol used in the
configuration is PIM-SM.
(
ip multicast protocol pim-sm is specified or no
command is specified)
show running-config
If a protocol other than PIM-SM is specified for the
multicast protocol, modify the configuration.
In addition, if no multicast protocol is specified in the
configuration, PIM-SM is specified for the multicast
protocol to be used. If PIM-DM is specified, multicast
protocols are not used in VRF.
3 If the Switch is used as the rendezvous point or BSR,
check the configuration to make sure that the loopback
interface is set for the target VRF.
show ip vrf
show running-config
Set the loopback interface number specified for the
rendezvous point or BSR to be the same as the
loopback interface number for the target VRF.
Also, set the IPv4 address for the loopback interface if
no address has been set.
4 If multiple VRFs are used, check whether a global
network or specific VRF occupies an unexpectedly
large number of multicast forwarding entries.
show ip 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:
ip pim vrf <vrf id> mcache-limit <number>
5 Check each VRF configuration by using the check
items in 3.9.1 Communication is not possible on the
IPv4 PIM-SM networks through 3.9.4 Multicast data is
forwarded twice in the IPv4 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.