Configuration of Multicast Listener Discovery (MLD) Snooping on Sx500 Series Stackable Switches

Objective

Multicast is the network layer technique that transmits data packets from one host to the selected hosts in a group. At the lower layer, the switch broadcasts the multicast traffic on all ports, even if only one host wants to receive it. Multicast Listener Discovery (MLD) Snooping is used to forward IPv6 multicast traffic only to the desired host(s).

When MLD snooping is enabled on the switch, it detects the MLD messages exchanged between the IPv6 router and the multicast hosts attached on the interface. It then maintains a table that restricts IPv6 multicast traffic and forwards it dynamically to those ports that want to receive it.

Configuration of multicast group is essential before the configuration of MLD snooping. To learn about multicast group configuration refer to the article, Creation and Configuration of IP Multicast Groups on Sx500 Series Stackable Switches.

The objective of this document is to explain how to configure MLD snooping on the Sx500 Series Stackable Switches.

Applicable Devices

• Sx500 Series Stackable Switches

Software Version

• 1.3.0.62

Configuration of MLD Snooping

Step 1. Log in to the web configuration utility on the switch and choose Multicast > MLD Snooping.

Note: Bridge Multicast Filtering and MLD Snooping must be enabled on the switch to perform MLD Snooping.

Step 2. Check the Enable check box in the MLD Snooping Status field to enable the switch to determine the hosts that have requested to receive multicast traffic.

Step 3. Click Apply to save the settings.

Note: MLD Snooping is allowed only on a static VLAN (A VLAN that is manually configured by VLAN ID and port assignments) and not on a dynamic VLAN (A VLAN that is dynamically assigned to the host by the switch when it gets connected. This operation requires the physical addresses of the hosts to be stored on the database of the switch in prior).

Step 4. Click the radio button of the desired VLAN ID and click Edit to configure MLD snooping on the VLAN.

The Edit MLD Snooping window appears:

Step 5. (Optional) Choose the desired VLAN ID from the VLAN ID drop-down list.

Step 6. Check the Enable check box of MLD Snooping Status to determine which hosts under the chosen VLAN have requested to send the multicast traffic. 

Step 7. (Optional) To enable auto learning of the ports to which the multicast router is connected, check the Enable check box of MRouter Ports Auto Learn.

Step 8. In the Query Robustness field, enter the robustness value, which ranges from 1 to 7, to indicate the number of MLD queries that the switch sends before it deletes a host that does not respond.

Step 9. In the Query Interval field, enter the time interval, which ranges from 30 to 18000 seconds, after which the switch sends the query messages. 

Step 10. In the Query Max Response Interval field, enter the delay that is used to determine the maximum response code inserted into the general queries. The time ranges from 5 to 20 seconds.

Step 11. Click one of the desired radio buttons of Last Member Query Counter to define the number of group-specific query messages sent before the switch assumes that there are no members of the host group to be queried on the interface.

• Use Default — The value equals to the value defined in the Query Robustness field.

• User Defined — Enter the desired value that ranges from 1 to 7 in the User Defined field.

Step 12. In the Last Member Query Interval field, enter the time interval for the switch to wait to receive a response from a group-specific message. The time ranges from 100 to 25500 ms.

Step 13. (Optional) To decrease the time taken by the switch to block the MLD traffic that does not belong to its member port, check the Enable check box in the Immediate Leave field.

Step 14. Click Apply to save the settings.