Enabling IGMP Snooping

Procedure

1. Run system-view

   The system view is displayed.

2. Run igmp-snooping enable

   IGMP snooping is enabled globally.

3. Run vlan vlan-id

   The VLAN view is displayed.

4. (Optional) Run l2-multicast forwarding-mode { ip | mac }

   The multicast forwarding mode in the VLAN is set to IP address-based or MAC address-based forwarding.

   By default, multicast flows are forwarded based on IP addresses.

   

   • Configure the forwarding mode of multicast flows in the VLAN before IGMP snooping is enabled in the VLAN. Enable IGMP snooping in the VLAN for the configuration to take effect.

   • After the multicast data forwarding mode is set to MAC address-based forwarding in a VLAN using this command, the VLAN cannot be configured as a multicast VLAN.

   • If the device forwards multicast data packets based on MAC addresses, do not use a group address on the network if the group address maps to the same multicast MAC address as a multicast IP address reserved for a protocol. Otherwise, the protocol that uses this multicast IP address cannot run normally. For example, OSPF uses 224.0.0.5 to send protocol packets. This multicast IP address maps to multicast MAC address 01-00-5E-00-00-05. If multicast data packets are forwarded based on MAC addresses and use multicast IP address 225.0.0.5 (also mapping to 01-00-5E-00-00-05), the OSPF protocol cannot run normally.

   • For the S5720-EI, S5735-L, S5735-S, S5735-S-I, S5735S-L, S5735S-S, S5735S-L-M, S6720-EI, and S6720S-EI, if the VLANIF interface corresponding to a VLAN is bound to a VPN instance but IGMP or PIM is disabled on this interface, multicast flows in this VLAN can only be forwarded based on MAC addresses. To forward multicast flows in the VLAN based on IP addresses, configure this VLAN as a user VLAN and another VLAN as a multicast VLAN. In this way, multicast flows can be replicated to the user VLAN from the multicast VLAN.

5. (Optional) Run l2-multicast router-port-discard

   The switch is disabled from forwarding multicast data to router ports in a VLAN.

   

   Before disabling the switch from forwarding multicast data to router ports in a VLAN, disable IGMP snooping in the VLAN. After setting the forwarding mode, enable IGMP snooping in the VLAN for the configuration to take effect.

6. Run igmp-snooping enable

   IGMP snooping is enabled in the VLAN.

   Run the igmp-snooping enable [ vlan { vlan-id1 [ to vlan-id2 ] } &<1-10> ] command in the system view to enable IGMP snooping in multiple VLANs.

   IGMP snooping cannot be used with N:1 (N > 1) VLAN mapping.

7. (Optional) Configure multicast-to-unicast conversion on the wireless side.
   

   To configure multicast-to-unicast conversion, you must configure complete WLAN basic services. For details, see WLAN Service Configuration Guide in the S5700 and S6700 V200R019C10 Configuration Guide - WLAN-AC.

   1. Run quit

      Return to the system view.

   2. Run wlan

      The WLAN view is displayed.

   3. Run traffic-profile name profile-name

      The traffic profile is displayed.

   4. Run igmp-snooping enable

      IGMP snooping is enabled in the traffic profile.

      After IGMP snooping is enabled in the traffic profile, an AP maintains Layer 2 multicast forwarding entries by listening on Report and Leave messages sent from downstream hosts so as to accurately forward multicast data to wireless users.