HP 2610-PWR - Manual (Page 101)

Multimedia Traffic Control with IP Multicast (IGMP)
How IGMP Operates
does not wait for the actual Querier to verify that there are no other group
members on port A3. If the switch itself is the Querier, it does not query port
A3 for the presence of other group members.
Note that Fast-Leave operation does not distinguish between end nodes on
the same port that belong to different VLANs. Thus, for example, even if all of
the devices on port A6 in figure 4-3 belong to different VLANs, Fast-Leave does
not operate on port A6.
Using Delayed Group Flush
This feature continues to filter IGMP-Left groups for a specified additional
period of time. The delay in flushing the group filter prevents stale traffic from
being forwarded by the server. Delayed Group Flush is enabled or disabled
for the entire switch.
ProCurve recommends that Delayed Group Flush be used whenever Fast
Leave or Forced Fast Leave are enabled on the Series 2610 and 2610-PWR
Switches. Note that this command must be executed in the configuration
context of the CLI.
Syntax: igmp delayedflush <time period>
Enables the switch to continue to flush IGMP-Left groups
for a specified period of time (0 - 255 seconds). The default
setting is
Disabled. To disable, reset the time period to zero.
Syntax: show igmp delayedflush
Displays the current setting for the switch.
Forced Fast-Leave IGMP
Forced Fast-Leave IGMP speeds up the process of blocking unnecessary IGMP
traffic to a switch port that is connected to multiple end nodes. (This feature
does not activate on ports where the switch detects only one end node). For
example, in figure 4-3, even if you configured Forced Fast-Leave on all ports
in the switch, the feature would activate only on port A6 (which has multiple
end nodes) when a Leave Group request arrived on that port.
When a port having multiple end nodes receives a Leave Group request from
one end node for a given multicast group “X”, Forced Fast-Leave activates and
waits a small amount of time to receive a join request from any other group
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