R3303-HP HSR6800 Routers IP Multicast Configuration Guide

Analysis

1. IGMP snooping or PIM snooping is not enabled.

2. PIM snooping is operating in a PIM-DM network.

Solution

1. Use the display current-configuration command to check the status of IGMP snooping and PIM

snooping.

2. If IGMP snooping is not enabled, enter system view and use the igmp-snooping command to

enable IGMP snooping globally. Then, enter VLAN view and use the igmp-snooping enable and

pim-snooping enable commands to enable IGMP snooping and PIM snooping for the VLAN.

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

enable PIM snooping for the VLAN.

4. Verify that PIM snooping is operating in a PIM-SM network. PIM snooping only supports the

PIM-SM mode but not the PIM-DM mode. If the network is in the PIM-DM mode, change it to the

PIM-SM mode.

Some downstream PIM routers cannot receive multicast data

Symptom

In a network with fragmented join/prune messages, some downstream PIM routers cannot receive

multicast data.

Analysis

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, PIM snooping

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

has the join suppression function enabled, the broadcast join/prune message fragments might suppress

the join messages of other PIM routers in the VLAN. As a result, some PIM routers cannot receive the

multicast data destined for a specific multicast group because their join messages are suppressed. To

solve this problem, disable the join suppression function on all PIM routers that connect to the PIM

snooping device in the VLAN.

Solution

1. Use the pim hello-option neighbor-tracking command to enable the neighbor tracking function on

the interfaces of PIM routers that connect to the PIM snooping device.

2. If a PIM router cannot be enabled with the neighbor tracking function, you have to disable PIM

snooping on the device.