Ip Routing Information Protocol - Bay Networks Nautica 200 Reference Manual

IP Routing Information Protocol

117237-C Rev. A
ARP is used if a device needs to send data to another station on
the network and it does not know the destination MAC address.
An ARP request is broadcast to all stations on the network. The
destination IP address for the desired station is included as part of
the message, so that only the station with this IP address responds
to the ARP request and all others discard it. The node whose IP
address was in the ARP request responds directly to the sender
with its own MAC address. This gives the sender the destination
MAC address needed to send the data.
The IP address date and MAC address data for each node is held
in a host cache or ARP table, so that the next time data needs to
be sent, the address can be obtained from the address information
in the ARP table.
One of the protocols used to build and maintain this picture of the
network is the Routing Information Protocol (RIP). This is a
distance vector protocol, which simply means that all the
decisions about which path to use are based upon the distance
between source and destination.
A router using RIP would first look at directly attached networks,
and these would be considered to be 1 hop away. Other networks
which are further away (i.e., not directly attached) would be n
hops away, where n is the number of hops needed to reach the
more distant network. If there are multiple paths to a network, the
path with the least number of hops is chosen as the best path, and
all other information about how to get to that network is
discarded.
Using RIP, the routers update each other every 30 seconds and
check to see if there is any new information that should be added
to the routing table. The entries in a routing table are allowed to
remain for 180 seconds. If no information about a remote network
is received in this time, the destination network is marked as
unreachable and removed from the routing table.
Understanding the Technology
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