ZyXEL Communications P-660HN-T1H User Manual

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 Chapter 7 LAN Setup
P-660HN-T1H User’s Guide
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probably adequate for most networks, unless you have an unusual network 
topology.
Both RIP-2B and RIP-2M sends the routing data in RIP-2 format; the difference 
being that RIP-2B uses subnet broadcasting while RIP-2M uses multicasting.
7.6.6  Multicast
Traditionally, IP packets are transmitted in one of either two ways - Unicast (1 
sender - 1 recipient) or Broadcast (1 sender - everybody on the network). 
Multicast delivers IP packets to a group of hosts on the network - not everybody 
and not just 1. 
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. IGMP 
version 2 (RFC 2236) is an improvement over version 1 (RFC 1112) but IGMP 
version 1 is still in wide use. IGMP version 3 supports source filtering, reporting or 
ignoring traffic from specific source address to a particular host on the network. If 
you would like to read more detailed information about interoperability between 
IGMP version 2 and version 1, please see sections 4 and 5 of RFC 2236. The class 
D IP address is used to identify host groups and can be in the range 224.0.0.0 to 
239.255.255.255. The address 224.0.0.0 is not assigned to any group and is used 
by IP multicast computers. The address 224.0.0.1 is used for query messages and 
is assigned to the permanent group of all IP hosts (including gateways). All hosts 
must join the 224.0.0.1 group in order to participate in IGMP. The address 
224.0.0.2 is assigned to the multicast routers group. 
The ZyXEL Device supports IGMP version 1 (IGMP-v1), IGMP version 2 (IGMP-
v2
) and IGMP version 3 (IGMP-v3). At start up, the ZyXEL Device queries all 
directly connected networks to gather group membership. After that, the ZyXEL 
Device periodically updates this information. IP multicasting can be enabled/
disabled on the ZyXEL Device LAN and/or WAN interfaces in the web configurator 
(LAN; WAN). Select None to disable IP multicasting on these interfaces.