ZyXEL Communications IES-708-22A - Manual (Page 148)

Chapter 18 IGMP
IES-708-22A User’s Guide
148
In IGMP proxy, an upstream interface is the port that is closer to the source (or the root of the
multicast tree) and is able to receive multicast traffic. There should only be one upstream
interface (also known as the query port) for one query VLAN on the IES-708-22A. A
downstream interface is a port that connects to a host (such as a computer).
The following figure shows a network example where A is the multicast source while
computers 1, 2 and 3 are the receivers. In the figure A is connected to the upstream interface
and 1, 2 and 3 are connected to the downstream interface.
Figure 66 IGMP Proxy Network Example
The IES-708-22A will not respond to IGMP join and leave messages on the upstream
interface. The IES-708-22A only responds to IGMP query messages on the upstream
interface. The IES-708-22A sends IGMP query messages to the hosts that are members of the
query VLAN.
The IES-708-22A only sends an IGMP leave messages via the upstream interface when the
last host leaves a multicast group.
In daisychain mode, Ethernet interface 1 is set as the upstream interface and Ethernet interface
2 and the DSL ports are set as downstream interfaces.
18.3 IGMP Status Screen
Use this screen to view current IGMP information.
To open this screen, click Advanced Application > IGMP.