Configuring Rip - 3Com 8807 Configuration Manual

292 C 30: RIP C
HAPTER
RIP Enabling and
Running

Configuring RIP

ONFIGURATION
If the RIP route is not updated (a router receives the update packets from the
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neighbor) when the Timeout timer expires, this route is regarded as
unreachable. The cost is set to 16.
If the Garbage-Collection timer expires, and the unreachable route receives no
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update packet from the same neighbor, the route will be completely deleted
from the routing table.
By default, the values of Period Update and Timeout timers are 30 seconds and
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180 seconds respectively. The value of Garbage-collection timer is four times
that of Period Update timer: 120 seconds.
The following section describes the procedure:
If RIP is enabled on a router for the first time, the router will broadcast or
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multicast the request packet to the adjacent routers. Upon receiving the
request packet, the RIP on each adjacent router responds with a packet
conveying its local routing table.
After receiving the response packets, the router, which has sent the request,
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will modify its own routing table. At the same time, the router sends trigger
modification packets to its adjacent routers running RIP and broadcasts
modification information, following split horizon mechanism. After receiving
trigger modification packets, the adjacent routers send trigger modification
packets to their respective adjacent routers. As a result, each router can obtain
and maintain the latest routing information.
RIP broadcasts its routing table to the adjacent routers every 30 seconds. The
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adjacent routers will maintain their own routing table after receiving the
packets and will select an optimal route, and then advertise the modification
information to their respective adjacent network so as to make the updated
route globally known. Furthermore, RIP uses the timeout mechanism to handle
the out-timed routes so as to ensure the real-timeliness and validity of the
routes.
RIP has become one of the actual standards of transmitting router and host routes
by far. It can be used in most of the campus networks and the regional networks
that are simple yet extensive. For larger and more complicated networks, RIP is not
recommended.
1 RIP basic configuration
RIP basic configuration includes:
Enabling RIP
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Enabling RIP on specified network
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If the link, which does not support broadcast or multicast packets, runs RIP, you
need to configure RIP to send any packet to the specified destination, establishing
RIP neighbors correctly.
2 RIP route management