Troubleshooting ipv6 pim snooping, Ipv6 pim snooping does not work, Symptom – H3C Technologies H3C S12500 Series Switches User Manual

Page 337: Analysis, Solution

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The output shows that Switch A will forward the multicast data intended for IPv6 multicast group

FF1E::101 to only Router C, and forward the multicast data intended for IPv6 multicast group
FF2E::101 to only Router D.

Troubleshooting IPv6 PIM snooping

IPv6 PIM snooping does not work

Symptom

IPv6 PIM snooping does not work.

Analysis

MLD snooping or IPv6 PIM snooping is not enabled on the switch.

Solution

1.

Use the display current-configuration command to determine the status of MLD snooping and IPv6

PIM snooping.

2.

If MLD snooping is not enabled, enter system view and use the mld-snooping command to enable
MLD snooping globally. Then, enter VLAN view and use the mld-snooping enable and

pim-snooping ipv6 enable commands to enable MLD snooping and IPv6 PIM snooping in the

VLAN.

3.

If IPv6 PIM snooping is not enabled, enter VLAN view and use the pim-snooping ipv6 enable
command to enable IPv6 PIM snooping in the VLAN.

Some downstream IPv6 PIM-capable routers cannot receive

multicast data

Symptom

In a network with fragmented join/prune messages, some downstream IPv6 PIM-capable routers cannot

receive multicast data.

Analysis

IPv6 PIM snooping cannot reassemble messages, and it cannot maintain the status of downstream

routers that the join/prune message fragments carry. To ensure the normal operation of the system, IPv6

PIM snooping must broadcast join/prune message fragments in the VLAN. However, if the VLAN has a

IPv6 PIM-capable router that has the join suppression function enabled, the broadcast join/prune
message fragments might suppress the join messages of other IPv6 PIM-capable routers in the VLAN. As

a result, some IPv6 PIM-capable routers cannot receive the multicast data addresses to a specific

multicast group because their join messages are suppressed. To solve this problem, disable the join

suppression function on all IPv6 PIM-capable routers that connect to the IPv6 PIM snooping-capable
switch in the VLAN.

Solution

1.

Use the pim ipv6 hello-option neighbor-tracking command to enable the neighbor tracking

function on the interfaces of IPv6 PIM-capable routers that connect to the IPv6 PIM

snooping-capable switch.

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