DES-3226L Layer 2
Fast Ethernet Switch User’s Guide
The following parameters can be set:
Parameter
Description
Query Interval (1-
65535)
The time between IGMP queries, set in seconds. The user may set a value
between 1 and 65535 seconds. The default is 125 seconds.
Max Response
(1-25)
Specifies the maximum amount of time allowed before sending a response
report. The user may set a value between 1 and 25 seconds.
Robustness
Variable (1-255)
Provides fine-tuning to allow for expected packet loss on a subnet. The value of
the robustness variable is used in calculating the following IGMP message
intervals:
• Group member interval—Amount of time that must pass before a multicast
router decides there are no more members of a group on a network. This interval
is calculated as follows: (robustness variable x query interval) + (1 x query
response interval).
• Other querier present interval—Amount of time that must pass before a
multicast router decides that there is no longer another multicast router that is
the querier. This interval is calculated as follows: (robustness variable x query
interval) + (0.5 x query response interval).
• Last member query count—Number of group-specific queries sent before the
router assumes there are no local members of a group. The default number is
the value of the robustness variable.
• By default, the robustness variable is set to 2. The user may wish to increase
this value if the subnet loses packets frequently.
Last Member
Query Interval (1-
65535)
The maximum amount of time between group-specific query messages,
including those sent in response to leave-group messages. The user may lower
this interval to reduce the amount of time it takes a router to detect the loss of the
last member of a group.
Querier State
This allows the switch to be specified as an IGMP Querier (sends IGMP query
packets) or a Non-Querier (does not send IGMP query packets). The user may
change the querier state to
Enabled
or
Disabled
.
Host Timeout (1 –
16711450)
Specifies the maximum amount of time a host can be a member of a multicast
group without the Switch receiving a host membership report. The default is 260
seconds.
Host Leave Timer
(1 – 16711450)
This specifies the maximum amount of time in seconds between the Switch
receiving a leave group message from a host, and the Switch issuing a group
membership query. If no response to the membership query is received before
the Leave Timer expires, the (multicast) forwarding entry for that host is deleted.
Route Timeout (1
– 16711450)
Specifies the maximum amount of time a route will remain in the switch’s can be
a member of a multicast group without the Switch receiving a host membership
report. The default is 260 seconds.
State
Enables or disables IGMP Snooping for the chosen VLAN.
100
