Igmp; Chapter 21 Igmp; Overview; What You Can Do In This Chapter - ZyXEL Communications CellPipe 7130 RG User Manual

C
H A P T E R

21.1 Overview

This chapter discusses the IGMP screens.
Traditionally, IP packets are transmitted in one of either two ways - Unicast (1
sender to 1 recipient) or Broadcast (1 sender to everybody on the network).
Multicast delivers IP packets to just a group of hosts on the network.
IGMP (Internet Group Multicast Protocol) is a network-layer protocol used to
establish membership in a multicast group - it is not used to carry user data. See
RFC 1112 and RFC 2236 for information on IGMP versions 1 and 2, respectively.

21.1.1 What You Can Do in this Chapter

• The IGMP screen lets you select the IGMP version to use as well as configure
the settings for IGMP
• The IGMP Source Configuration screen lets you set the server where the
CellPipe 7130 RG gets the multicast group information
263).

21.1.2 What You Need to Know

IP Multicast Addresses
In IPv4, a multicast address allows a device to send packets to a specific group of
hosts (multicast group) in a different sub-network. A multicast IP address
represents a traffic receiving group, not individual receiving devices. IP addresses
in the Class D range (224.0.0.0 to 239.255.255.255) are used for IP multicasting.
Certain IP multicast numbers are reserved by IANA for special purposes (see the
IANA web site for more information).
IGMP Snooping
A layer-2 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
CellPipe 7130 RG User's Guide
(Section 21.2 on page 263).
21

IGMP

(Section 21.2 on page
261