Chapter 10 Igmp Snooping; Igmp Snooping; Igmp Snooping Screen; Figure 58 Igmp Snooping - ZyXEL Communications AAM1212 User Manual

This chapter describes the IGMP Snooping screen.

10.1 IGMP Snooping

IGMP (Internet Group Multicast Protocol) is a session-layer protocol used to establish
membership in a multicast group - it is not used to carry user data. Refer to RFC 1112 and
RFC 2236 for information on IGMP versions 1 and 2 respectively.
A switch can passively snoop on IGMP Query, Report and Leave (IGMP version 2) packets
transferred between IP multicast routers/switches and IP multicast hosts to learn the IP
multicast group membership. It checks 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. The switch discards multicast traffic destined for multicast groups that it does not
know. IGMP snooping generates no additional network traffic, allowing you to significantly
reduce multicast traffic passing through your switch.

10.2 IGMP Snooping Screen

Click Advanced Application and then IGMP Snooping in the navigation panel to display the
IGMP Snooping screen as shown next. Use this screen to turn IGMP snooping off or on and
view information collected by IGMP snooping.

Figure 58 IGMP Snooping

Chapter 10 IGMP Snooping

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