Prestige 2301R/RL-P1C Support Notes
All contents Copyright (c) 2007 ZyXEL Communications Corporation.
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Using IP Multicast
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What is IP Multicast ?
Traditionally, IP packets are transmitted in two ways - unicast or broadcast. Multicast is a third way to
deliver IP packets to a group of hosts. Host groups are identified by class D IP addresses, i.e., those with
"1110" as their higher-order bits. In dotted decimal notation, host group addresses range from 224.0.0.0 to
239.255.255.255. Among them, 224.0.0.1 is assigned to the permanent IP hosts group, and 224.0.0.2 is
assigned to the multicast routers group.
IGMP (Internet Group Management Protocol) is the protocol used to support multicast groups. The latest
version is version 2 (see RFC2236). IP hosts use IGMP to report their multicast group membership to any
