Operation with or without IP addressing

You can configure IGMP on VLANs that do not have IP addressing. The benefit of IGMP without IP addressing is a reduction in the number of IP addresses you have to use and configure. This can be significant in a network with a large number of VLANs. The limitation on IGMP without IP addressing is that the switch cannot become Querier on any VLANs for which it has no IP address—so the network administrator must ensure that another IGMP device will act as Querier. It is also advisable to have an additional IGMP device available as a backup Querier.

Table 2: Comparison of IGMP operation with and without IP addressing

IGMP function available with IP addressing configured on the VLAN

Available without IP addressing?

Operating differences without an IP address

Forward multicast group traffic to any port on the VLAN that has received a join request for that multicast group.

Yes

None

Forward join requests (reports) to the Querier.

Yes

None

Configure individual ports in the VLAN to Auto (the default)/Blocked, or Forward.

Yes

None

Configure IGMP traffic forwarding to normal or high-priority forwarding.

Yes

None

Age-out IGMP group addresses when the last IGMP client on a port in the VLAN leaves the group.

Yes

Requires that another IGMP device in the VLAN has an IP address and can operate as Querier. This can be a multicast router or another switch configured for IGMP operation. (Hewlett Packard Enterprise recommends that the VLAN also include a device operating as a backup Querier in case the device operating as the primary Querier fails for any reason.)

Support Fast-Leave IGMP and Forced Fast-Leave IGMP (below.)

Yes

Support automatic Querier election.

No

Querier operation not available.

Operate as the Querier.

No

Querier operation not available.

Available as a backup Querier.

No

Querier operation not available.