Robustness Value
Adjust this variable according to expected packet loss. If packet loss on the VLAN is expected to be high, the
Robustness Variable
should be increased to accommodate increased packet loss.This entry field allows an
entry of 1 to 255. Default = 2.
Last Member Query Interval
This field specifies the maximum amount of time between group-specific query messages, including those sent
in response to leave group messages. Default = 1.
Host Timeout
This is the maximum amount of time in seconds allowed for a host to continue membership in a multicast
group without the Switch receiving a host membership report. Default = 260.
Router Timeout
This is the maximum amount of time in seconds a route is kept in the forwarding table without receiving a
membership report. Default = 260.
Leave Timer
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.
Querier State
Choose
Enabled
to enable transmitting IGMP Query packets or
Disabled
to disable.The default is
Disabled
.
Querier Router Behavior
This read-only field describes the behavior of the router for sending query packets.
Querier
will denote that the
router is sending out IGMP query packets.
Non-Querier
will denote that the router is not sending out IGMP
query packets.This field will only read
Querier
when the
Querier State
and the
State
fields have been
Enabled.
State
Select
Enabled
to implement IGMP Snooping.This field is
Disabled
by default.
Click
Apply
to implement the new settings. Click the Show All IGMP Group Entries link to return to the
Current IGMP Snooping Group Entries
window.
Static Router Ports
A static router port is a port that has a multicast router attached to it. Generally, this router would have a connection to a WAN or to the Internet. Establishing a
router port will allow multicast packets coming from the router to be propagated through the network, as well as allowing multicast messages (IGMP) coming
from the network to be propagated to the router.
A router port has the following behavior:
•
All IGMP Report packets will be forwarded to the router port.
•
IGMP queries (from the router port) will be flooded to all ports.
•
All UDP multicast packets will be forwarded to the router port. Because routers do not send IGMP reports or implement IGMP snooping, a multicast
router connected to the router port of a Layer 3 switch would not be able to receive UDP data streams unless the UDP multicast packets were all
forwarded to the router port.
A router port will be dynamically configured when IGMP query packets, RIPv2 multicast, DVMRP multicast or PIM-DM multicast packets are detected flowing
into a port.
Open the
IGMP
folder and the click on the
Static Router Ports Entry
link to open the
Current Static Router Ports Entries
page, as shown
below.
Figure 6- 19. Current Static Router Ports Entries window
The
Current Static Router Ports Entries
page (shown above) displays all of the current entries to the Switch's static router port table.To modify an
entry, click the
Modify
button.This will open the
Static Router Ports Settings
page, as shown below.
41
Allied Telesyn AT-9724TS High-Density Layer 3 Stackable Gigabit Ethernet Switch
