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4 rip setup, 5 multicast – ZyXEL Communications P-2900-4HB User Manual

Page 56

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Chapter 5 LAN Setup

P-2900-4HB User’s Guide

56

5.4.4 RIP Setup

RIP Directions

The sending and receiving of RIP packets can occur in the following ways:

• Both - the ZyXEL Device will broadcast its routing table periodically and

incorporate the RIP information that it receives.

• In Only - the ZyXEL Device will not send any RIP packets but will accept all RIP

packets received.

• 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.

RIP Versions

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.

5.4.5 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