Multimedia Traffic Control with IP Multicast (IGMP)

How IGMP Operates

Supported Standards and RFCs

ProCurve’s implementation of IGMP supports the following standards and operating capabilities:

RFC2236 (IGMP V.2, with backwards support for IGMP V.1)

IETF draft for IGMP and MLD snooping switches (for IGMP V1, V2 V3)

Full IGMPv2 support as well as full support for IGMPv1 Joins.

Ability to operate in IGMPv2 Querier mode on VLANs with an IP address.

The ProCurve implementation is subject to the following restrictions:

Interoperability with RFC3376 (IGMPv3)

Interoperability with IGMPv3 Joins. When the switch receives an IGMPv3 Join, it accepts the host request and begins forwarding the IGMP traffic. This means ports that have not joined the group and are not connected to routers or the IGMP Querier will not receive the group's multicast traffic.

No support for the IGMPv3 “Exclude Source” or “Include Source” options in the Join Reports. Rather, the group is simply joined from all sources.

No support for becoming a version 3 Querier. The switch will become a version 2 Querier in the absence of any other Querier on the network.

N o t e

IGMP is supported in the HP MIB, rather than the standard IGMP MIBs, as the

 

latter reduce Group Membership detail in switched environments.

 

 

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. See the following table.

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