ZyXEL VSG1432-B101 User Guide - Page 199

What You Can Do in this What You Need to Know

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CHAPTER 14 IGMP 14.1 Overview 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, RFC 2236, and RFC 3376 for information on IGMP versions 1, 2, and 3 respectively. 14.1.1 What You Can Do in this Chapter • Use the IGMP General screen to configure general IGMP proxy and IGMP packet processing settings (Section 14.2 on page 202). • Use the IGMP Filter screens to control IGMP access (Section 14.3 on page 204). • Use the IGMP ACL screens to block or allow access to specific multicast media channels (Section 14.4 on page 209). 14.1.2 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 VSG1432-B101 Series User's Guide 199

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VSG1432-B101 Series User’s Guide
199
C
HAPTER
14
IGMP
14.1
Overview
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, RFC 2236, and RFC 3376 for information on IGMP versions 1, 2, and 3
respectively.
14.1.1
What You Can Do in this Chapter
Use the
IGMP General
screen to configure general IGMP proxy and IGMP
packet processing settings (
Section 14.2 on page 202
).
Use the
IGMP Filter
screens to control IGMP access (
Section 14.3 on page
204
).
Use the
IGMP ACL
screens to block or allow access to specific multicast media
channels (
Section 14.4 on page 209
).
14.1.2
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