IGMP Snooping

To support selective IPv4 Multicast forwarding, bridge Multicast filtering must be enabled (in Multicast Properties). The IGMP Snooping must be enabled globally and for each relevant VLAN in the IGMP Snooping page.

To enable IGMP Snooping and identify the device as an IGMP Snooping Querier on a VLAN, follow these steps:

Procedure

Step 1

Click Multicast > IPv4 Multicast Configuration > IGMP Snooping.

  • IGMP Snooping Status—Select to enable IGMP snooping globally on all interfaces.

  • IGMP Querier Status—Select to enable IGMP querier globally on all interfaces.

Step 2

IGMP Snooping is only operational when Bridge Multicast Filtering is enabled. You can enable it here: Multicast Properties.

Step 3

To configure IGMP on an interface, select a static VLAN and click Edit. Enter the following fields:

OptionDescription

VLAN ID

Select The VLAN Id from the dropdown list.

IGMP Snooping Status

Select to enable IGMP Snooping on the VLAN. The device monitors network traffic to determine which hosts have asked to be sent Multicast traffic.

MRouter Ports Auto Learn

Select to enable Auto Learn of the Multicast router.

Immediate Leave

Select to enable the switch to remove an interface that sends a leave message from the forwarding table without first sending out MAC-based general queries to the interface. When an IGMP Leave Group message is received from a host, the system removes the host port from the table entry. After it relays the IGMP queries from the Multicast router, it deletes entries periodically if it doesn’t receive any IGMP membership reports from the Multicast clients. When enabled, this feature reduces the time it takes to block unnecessary IGMP traffic sent to a device port.

Last Member Query Counter

Number of MLD group-specific queries sent before the device assumes that there are no more members for the group, if the device is the elected querier.

  • Use Query Robustness (x)—The number in parentheses is the current query robustness value.

  • User Defined—Enter a user-defined value.

IGMP Querier Status

Select to enable this feature. This feature is required if there’s no Multicast router.

IGMP Querier Election

IGMP Querier Election—Whether the IGMP querier election is enabled or disabled. If the IGMP Querier election mechanism is enabled, the IGMP Snooping querier supports the standard IGMP Querier election mechanism specified in RFC3810.

If the IGMP Querier election mechanism is disabled, the IGMP Snooping querier delays sending General Query messages for 60 seconds after it was enabled, and if there’s no other querier, it starts sending General Query messages. It stops sending General Query messages when it detects another querier. The IGMP Snooping Querier resumes sending General Query messages if it does hear another querier for a Query Passive interval that equals: Robustness * (Query Interval) + 0.5 * Query Response Interval.

IGMP Querier Version

Select the IGMP version to be used if the device becomes the elected querier. Select IGMPv3 if there are switches and/or Multicast routers in the VLAN that perform source-specific IP Multicast forwarding. Otherwise, select IGMPv2.

Querier Source IP Address

The IP address of the device source interface to be used in messages sent. In MLD this address is selected automatically by the system.

  • Auto—The system takes the source IP address from the IP address defined on the outgoing interface.

  • User Defined—Enter a user-defined IP address.

Step 4

Click Apply. The Running Configuration file is updated.

Note

Changes in IGMP Snooping timers configuration, such as: Query Robustness, Query Interval etc. don’t take effect on timers which already created.