3 multicast, 3 configuring lan ip – ZyXEL Communications G.SHDSL.bis 4-port Security Gateway P-793H User Manual
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P-793H User’s Guide
Chapter 6 LAN Setup
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• Out Only - the ZyXEL Device will send out RIP packets but will not accept any RIP
packets received.
• None - the ZyXEL Device will not send any RIP packets and will ignore any RIP
packets received.
The Version field controls the format and the broadcasting method of the RIP packets that the
ZyXEL Device sends (it recognizes both formats when receiving). RIP-1 is universally
supported; but RIP-2 carries more information. RIP-1 is 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.
6.2.3 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. 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 both IGMP version 1 (IGMP-v1) and IGMP version 2 (IGMP-
v2). 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.
6.3 Configuring LAN IP
Use this screen to set the LAN IP address of your ZyXEL Device. Click LAN > IP. See
for background information.