ZyXEL Communications 623ME-T Modem User Manual


 
Prestige 623ME-T User’s Guide
LAN Setup 4-3
These parameters should work for the majority of installations. If your ISP gives you explicit DNS server
address(es), read the embedded web configurator help regarding what fields need to be configured.
4.4.2 IP Address and Subnet Mask
Refer to the IP Address and Subnet Mask section in the Wizard Setup chapter for this information.
4.4.3 RIP Setup
RIP (Routing Information Protocol) allows a router to exchange routing information with other routers. The
RIP Direction field controls the sending and receiving of RIP packets. When set to:
1. Both - the Prestige will broadcast its routing table periodically and incorporate the RIP information that
it receives.
2. In Only - the Prestige will not send any RIP packets but will accept all RIP packets received.
3. Out Only - the Prestige will send out RIP packets but will not accept any RIP packets received.
4. None - the Prestige 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 Prestige 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.
4.4.4 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 Prestige supports both IGMP version 1 (IGMP-v1) and IGMP version 2 (IGMP-v2). At start up, the
Prestige queries all directly connected networks to gather group membership. After that, the Prestige
periodically updates this information. IP multicasting can be enabled/disabled on the Prestige LAN interface
in the web configurator. Select None to disable IP multicasting.