Hirschmann GREYHOUND GRS1020, Справочное руководство

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Network load control
10.2 Multicasts
117
UM Config GRS
Release 8.0 09/2019
The IGMP snooping method also makes it possible for switches to use the
IGMP
function. A switch
stores the MAC addresses derived from IP addresses of the Multicast receivers as recognized
Multicast addresses in its MAC address table (FDB). In addition, the switch identifies the ports on
which it has received reports for a specific Multicast address. In this way, the switch forwards
Multicast packets only to ports to which Multicast receivers are connected. The other ports do not
receive these packets.
A special feature of the device is the possibility of determining the processing of data packets with
unknown Multicast addresses. Depending on the setting, the device discards these data packets
or forwards them to every port. By default, the device transmits the data packets only to ports with
connected devices, which in turn receive query packets. You also have the option of additionally
sending known Multicast packets to query ports.
Setting IGMP snooping
Perform the following steps:

Specifying the settings for a port:

Specifying the settings for a VLAN:

Open the Switching > IGMP Snooping > Global dialog.

To enable the function, select the On radio button in the Operation frame.
When the IGMP Snooping function is disabled, the device behaves as follows:

The device ignores the received query and report messages.

The device forwards (floods) received data packets with a Multicast address as the
destination address to every port.

To save the changes temporarily, click the button.

Open the Switching > IGMP Snooping > Configuration dialog, Port tab.

To activate the IGMP Snooping function on a port, mark the checkbox in the Active column
for the relevant port.

To save the changes temporarily, click the button.

Open the Switching > IGMP Snooping > Configuration dialog, VLAN ID tab.

To activate the IGMP Snooping function for a specific VLAN, mark the checkbox in the Active
column for the relevant VLAN.

To save the changes temporarily, click the button.