Enhancements in Release F.02.02

Operation and Enhancements for Multimedia Traffic Control (IGMP)

IGMP Function Available With IP Addressing

Available

Operating Differences Without an IP Address

Configured on the VLAN

Without IP

 

 

Addressing?

 

Drop multicast group traffic for which there

Yes

None

have been no join requests from IGMP clients

 

 

connected to ports on the VLAN.

 

 

 

 

 

Forward multicast group traffic to any port on

Yes

None

the VLAN that has received a join request for

 

 

that multicast group.

 

 

 

 

 

Forward join requests (reports) to the Querier.

Yes

None

 

 

 

Configure individual ports in the VLAN to Auto

Yes

None

(the default)/Blocked, or Forward.

 

 

 

 

 

Configure IGMP traffic forwarding to normal or

Yes

None

high-priority forwarding.

 

 

 

 

 

 

 

 

Age-Out IGMP group addresses when the last

Yes

Requires that another IGMP device in the VLAN has an IP

IGMP client on a port in the VLAN leaves the

 

address and can operate as Querier. This can be a multi-

group.

 

cast router or another switch configured for IGMP oper-

 

 

ation. (HP recommends that the VLAN also include a

Support Fast-Leave IGMP (below) and Forced

Yes

device operating as a backup Querier in case the device

Fast-Leave IGMP (page 212).

 

operating as the primary Querier fails for any reason.

 

 

 

Support automatic Querier election.

No

Querier operation not available.

 

 

 

Operate as the Querier.

No

Querier operation not available.

 

 

 

Provide a backup Querier.

No

Querier operation not available.

 

 

 

Fast-Leave IGMP

IGMP Operation Presents a "Delayed Leave" Problem. Where multiple IGMP clients are connected to the same port on an IGMP device (switch or router), if only one IGMP client joins a given multicast group, then later sends a Leave Group message and ceases to belong to that group, the IGMP device retains that IGMP client in its IGMP table and continues forwarding IGMP traffic to the IGMP client until the Querier triggers confirmation that no other group members exist on the same port. This means that the switch continues to transmit unnecessary multicast traffic through the port until the Querier renews multicast group status.

Fast-Leave IGMP Reduces Leave Delays. Fast-Leave IGMP operates on a port if an IGMP client connects to the port and there are no other end nodes detected on that port. In this case, when the client leaves a multicast group, Fast-Leave IGMP automatically accelerates the blocking of further,

210