Chapter 39 Multicast
GS1920v2 Series User’s Guide
224
39.3  IGMP Snooping
Click SWITCHING > Multicast > IPv4 Multicast > IGMP Snooping to display the screen as shown. See 
Section 39.1 on page 219 for more information on multicasting.
Figure 153   SWITCHING > Multicast > IPv4 Multicast > IGMP Snooping
The following table describes the labels in this screen.
Table 105   SWITCHING > Multicast > IPv4 Multicast > IGMP Snooping
LABEL DESCRIPTION
Active Enable the switch button to enable IGMP Snooping to forward group multicast traffic only to 
ports that are members of that group.
Querier Select this to allow the Switch to send IGMP General Query messages to the VLANs with the 
multicast hosts attached.
Report Proxy Select this to allow the Switch to act as the IGMP report proxy and leave proxy. It will report 
group changes to a connected multicast router.
The Switch not only checks IGMP packets between multicast routers or switches and multicast 
hosts to learn the multicast group membership, but also replaces the source MAC address in 
an IGMP v1/v2 report with its own MAC address before forwarding to the multicast router or 
switch. When the Switch receives more than one IGMP v1/v2 join report that requests to join 
the same multicast group, it only sends a new join report with its MAC address. This helps 
reduce the number of multicast join reports passed to the multicast router or switch.
The Switch sends a leave message with its MAC address to the multicast router or switch only 
when it receives the leave message from the last host in a multicast group.
Host Timeout Specify the time (from 1 to 16711450) in seconds that elapses before the Switch removes an 
IGMP group membership entry if it does not receive report messages from the port.