Allied Telesis AT-S62 - Manual (Page 327)

AT-S62 Management Software Menus Interface User’s Guide
Section II: Advanced Operations 327
The options in the menu are defined below:
1 - IGMP Snooping Status
Enables and disables IGMP snooping on the switch. After selecting
this option, type E to enable or D to disable this feature.
2 - Multicast Host Topology
Defines whether there is only one host node per switch port or multiple
host nodes per port. Possible settings are Single-Host/Port (Edge) and
Multiple Host/Ports (Intermediate).
The Single-Host/Port setting is appropriate when there is only one host
node connected to each port on the switch. This setting causes the
switch to immediately stop sending multicast packets out a switch port
when a host node signals its desire to leave a multicast group by
sending a leave request or when the host node stops sending reports.
The switch responds by immediately ceasing the transmission of
additional multicast packets out the port where the host node is
connected.
The Multi-Host setting is appropriate if there is more than one host
node connected to a switch port, such as when a port is connected to
an Ethernet hub to which multiple host nodes are connected. With this
setting selected the switch continues sending multicast packets out a
port even after it receives a leave request from a host node on the port.
This ensures that the remaining active host nodes on the port will
continue to receive the multicast packets. Only after all the host nodes
connected to a switch port have transmitted leave requests or have
timed out will the switch stop sending multicast packets out the port.
If a switch has a mixture of host nodes, that is, some connected
directly to the switch and others through an Ethernet hub, you should
select the Multi-Host Port (Intermediate) selection.
3 - Host/Router Timeout Interval
Specifies the time period in seconds at which the switch determines
that a host node has become inactive. An inactive host node is a node
that has not sent an IGMP report during the specified time interval. The
range is from 0 second to 86,400 seconds (24 hours). The default is
260 seconds.
This parameter also specifies the time interval used by the switch in
determining whether a multicast router is still active. The switch makes
the determination by watching for queries from the router. If the switch
does not detect any queries from a multicast router during the
specified time interval, it assumes that the router is no longer active on
the port.
The actual timeout may be ten seconds less that the specified value.
For example, a setting of 25 seconds can result in the switch
classifying a host node or multicast router as being inactive after just
15 seconds. A setting of 10 seconds or less can result in the
immediate timeout of an inactive host node or router.