Igmp Snooping; Chapter 13 Igmp Snooping; Overview; Igmp Snooping Settings - ZyXEL Communications XGS1250-12 User Manual

13.1 Overview

This chapter shows you how to configure the various multicast features.
Traditionally, IP packets are transmitted in one of either two ways – Unicast (one sender to one recipient)
or Broadcast (one sender to everybody on the network). Multicast delivers IP packets to just a group of
hosts on the network.
IGMP (Internet Group Management Protocol) is a network-layer protocol used to establish membership
in a multicast group – it is not used to carry user data. Refer to RFC 1112, RFC 2236 and RFC 3376 for
information on IGMP versions 1, 2, and 3 respectively.
Note: You must enable IGMP snooping to use the IPTV service.
IGMP snooping is enabled, and the IGMP Static Router Port is set to Auto by default. The
port can be used as an IGMP router port.

IGMP Snooping

The Switch can passively snoop on IGMP packets transferred between IP multicast routers or switches
and IP multicast hosts to learn the IP multicast group membership. It checks the IGMP packets passing
through it, picks out the group registration information, and configures multicasting accordingly. IGMP
snooping allows the Switch to learn multicast groups without you having to manually configure them.
The Switch forwards multicast traffic destined for multicast groups (that it has learned from IGMP
snooping or that you have manually configured) to ports that are members of that group. IGMP
snooping generates no additional network traffic, allowing you to significantly reduce multicast traffic
passing through your Switch.

13.2 IGMP Snooping Settings

Click IGMP Snooping in the navigation panel to display the screen as shown next.
IGMP Snooping
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