Troubleshooting igmp snooping, Layer 2 multicast forwarding cannot function, Symptom – H3C Technologies H3C S12500 Series Switches User Manual

Page 59: Analysis, Solution

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Subvlan flags: R-Real VLAN, C-Copy VLAN

Vlan(id):100.

Total 1 IP Group(s).

Total 1 IP Source(s).

Total 1 MAC Group(s).

Router port(s):total 1 port(s).

GE3/0/1 (D)

IP group(s):the following ip group(s) match to one mac group.

IP group address:224.1.1.1

(0.0.0.0, 224.1.1.1):

Host port(s):total 1 port(s).

GE3/0/3 (D)

MAC group(s):

MAC group address:0100-5e01-0101

Host port(s):total 1 port(s).

GE3/0/3

Troubleshooting IGMP snooping

Layer 2 multicast forwarding cannot function

Symptom

Layer 2 multicast forwarding cannot function.

Analysis

IGMP snooping is not enabled.

Solution

1.

Use display current-configuration command to view the running status of IGMP snooping.

2.

If IGMP snooping is not enabled, use the igmp-snooping command to enable IGMP snooping
globally, and then use the igmp-snooping enable command to enable IGMP snooping in VLAN

view.

3.

If IGMP snooping is disabled only for the corresponding VLAN, use the igmp-snooping enable
command in VLAN view to enable IGMP snooping in the corresponding VLAN.

Configured multicast group policy fails to take effect

Symptom

Although a multicast group policy has been configured to allow hosts to join specific multicast groups, the
hosts can still receive multicast data addressed to other multicast groups.

Analysis

The ACL rule is incorrectly configured.

The multicast group policy is not correctly applied.

The function of dropping unknown multicast data is not enabled, so unknown multicast data is
flooded.

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