Automatic Fast-Leave Igmp - HP procurve 8100fl series Management And Configuration Manual

Table 10-1.Comparison of IGMP Operation With and Without IP Addressing
IGMP Function Available With IP Addressing
Configured on the VLAN
Forward multicast group traffic to any port on
the VLAN that has received a join request for
that multicast group.
Forward join requests (reports) to the Querier.
Configure individual ports in the VLAN to Auto
(the default)/Blocked, or Forward.
Age-Out IGMP group addresses when the last
IGMP client on a port in the VLAN leaves the
group.
Support Fast-Leave IGMP and Forced Fast-
Leave IGMP (below).
Support automatic Querier election.
Operate as the Querier.
Available as a backup Querier.
Available
Without IP
Addressing?
Yes
Yes
Yes
Yes
Yes
No
No
No

Automatic Fast-Leave IGMP

This feature selectively forwards joined multicast traffic by filtering unjoined
mulitcast traffic (except for always-fowarded traffic) toward the Querier or
multicast routers, and out of IGMP-forward ports.
If a switch port has the following characteristics, then the Fast-Leave
operation will automatically apply:
1. Connected to only one end node
2. The end node currently belongs to a multicast group; i.e. is an IGMP client
3. The end node subsequently leaves the multicast group
When Fast-Leave operates, the switch does not need to wait for the Querier
status update interval, but instead immediately removes the IGMP client from
its IGMP table and ceases transmitting IGMP traffic to the client. (If the switch
detects multiple end nodes on the port, automatic Fast-Leave does not
activate—regardless of whether one or more of these end nodes are IGMP
clients.)
Multimedia Traffic Control with IP Multicast (IGMP)
Operating Differences Without an IP Address
None
None
None
Requires that another IGMP device in the VLAN has an IP
address and can operate as Querier. This can be a multi­
cast router or another switch configured for IGMP oper­
ation. (HP 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.
Querier operation not available.
Querier operation not available.
Querier operation not available.
How IGMP Operates
10-11