Operation Manual

30
IGMP Proxy
Multicasting is useful when the same data needs to be sent to more than one hosts. Using multicasting as
opposed to sending the same data to the individual hosts uses less network bandwidth. The multicast feature
also enables you to receive multicast video stream from multicast servers.
IP hosts use Internet Group Management Protocol (IGMP) to report their multicast group memberships to
neighboring routers. Similarly, multicast routers use IGMP to discover which of their hosts belong to multicast
groups. This device supports IGMP proxy that handles IGMP messages. When enabled, this device acts as a
proxy for a LAN host making requests to join and leave multicast groups, or a multicast router sending
multicast packets to multicast group on the WAN side.
When a host wishes to join a multicast group, it sends IGMP REPORT message to the device’s IGMP
downstream interface. The proxy sets up a multicast route for the interface and host requesting the video
content. It then forwards the Join to the upstream multicast router. The multicast IP traffic will then be
forwarded to the requesting host. On a leave, the proxy removes the route and then forwards the leave to the
upstream multicast router.
The IGMP Proxy page allows you to enable multicast on WAN and LAN interfaces. The LAN interface is
always served as downstream IGMP proxy, and you can configure one of the available WAN interfaces as the
upstream IGMP proxy.
 Upstream: The interface that IGMP requests from hosts is sent to the multicast router.
 Downstream: The interface data from the multicast router are sent to hosts in the multicast
group database.
Field Description
IGMP Proxy Enable/disable IGMP proxy feature
Proxy Interface The upstream WAN interface is selected here.
Apply Changes
Click to save the setting to the configuration.