Allied Telesis AT-S39 - Manual (Page 233)

AT-S39 User’s Guide
233
Snoop Topology
Defines whether there is only one host node per switch port or
multiple host nodes per port. Possible settings are Edge (Single-
Host/Port) and Intermediate (Multi-Host/Port).
The Edge (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 and times-out. The switch
forwards the leave request to the router and simultaneously
ceases transmission of any further multicast packets out the port
where the host node is connected.
The Intermediate (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 of 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 Intermediate Multi-Host Port selection.
Host/Router Timeout Interval
Specifies the time period in seconds after 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 1 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during the specified time interval, it assumes that the router is no
longer active on the port.
Maximum Multicast Groups
Specifies the maximum number of multicast groups the switch
will learn. The range is 1 to 2048 groups. The default is 256
multicast groups.