ZyXEL Communications ONU-2024 Series, User Manual

Page: 131 / 268

ONU User’s Guide
131
C
H A P T E R
1 9
Multicast
19.1 Overview
This chapter shows you how to configure various multicast features.
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 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.
19.1.1 What You Can Do in the Multicast Screens
• The Multicast Status screen lets you view multicast group information ( Section 19.2 on
page 132 ).
• The Multicast Setting screen lets you configure various multicast settings, such as IGMP
snooping, host timeout, leave timeout, and so on ( Section 19.3 on page 133 ).
• The IGMP Snooping VLAN screen lets you configure the ONU to automatically locate
VLANS connected to its network ( Section 19.4 on page 135 ).
• The IGMP Filtering Profile screen lets you specify a range of multicast groups that
clients connected to the ONU are able to join ( Section 19.5 on page 136 ).
• The MVR screen lets you create multicast VLANs and select the receiver port(s) and a
source port for each multicast VLAN ( Section 19.7 on page 139 ).
• The Group Configuration screen lets you configure MVR IP multicast group address(es)
( Section 19.8 on page 141 ).
19.1.2 What You Need to Know About the Multicast Screens
The following terms and concepts may help as you read through this chapter.
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 subnetwork. 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).