ZyXEL Communications ADSL2+4 Modem User Manual


 
Chapter 7 LAN Setup
P-660H-T1v3s User’s Guide
101
7.6.5 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:
Both - the P-660H-T1v3s will broadcast its routing table periodically and
incorporate the RIP information that it receives.
In Only - the P-660H-T1v3s will not send any RIP packets but will accept all RIP
packets received.
Out Only - the P-660H-T1v3s will send out RIP packets but will not accept any
RIP packets received.
None - the P-660H-T1v3s 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 P-660H-T1v3s 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.
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.