3com 3031 Instruccion De Instalación

For the parameter explanation of VPN instance, refer to Part VIII “MPLS”.

RIP is an abbreviation for Routing Information Protocol. It is a relatively simple 
dynamic routing protocol, but it is widely applied in practice.

RIP is a kind of Distance-Vector (D-V) algorithm-based protocol and exchanges 
routing information via UDP packets. It employs Hop Count to measure the 
distance to the destination host, which is called Routing Cost. In RIP, the hop 
count from a router to its directly connected network is 0, and that to a network 
which can be reached through another router is 1, and so on. To restrict the time 
to converge, RIP prescribes that the cost is an integer ranging from 0 and 15. The 
hop count equal to or exceeding 16 is defined as infinite, that is to say, the 
destination network or the host is unreachable.

To improve performance and avoid the creation of routing loop, RIP supports both 
Split Horizon and Poison Reverse. Besides, RIP can also redistribute routes from 
other routing protocols.

Each router running RIP manages a route database, which contains routing entries 
to all the reachable destinations in the network. These routing entries contain the 
following information:

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Destination address: IP address of a host or a network.

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Next hop address: The address of the next router that a router will pass 
through for reaching the destination.

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Interface: The interface through which the IP packet should be forwarded.

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Cost: The cost for the router to reach the destination, which should be an 
integer in the range of 0 to 15.

■

Timer: Duration from the last time that the routing entry is modified till now. 
The timer is reset to 0 whenever a routing entry is modified.

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Route flag: A label distinguishing routes of internal routing protocols from 
those of external routing protocols.

In RFC1058, RIP is described as controlled by three timers, Period update, Timeout 
and Garbage-collection,

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Timer Period update is to send all RIP routing information to all neighbors;