Routing information protocol rip

Routing information protocol involves an important algorithm , behrman - Ford algorithm .

The key point related to routing is the cost value , Be careful ： It is meaningless to compare the cost values between different routing protocols , This is because different agreements have different criteria .

RIP Is based on the number of hops （ The number of forwarding through the router ） As the criterion of cost ,RIP The working radius of is 15 jump , If the cost of a route reaches 16 Jumping time , The target network segment will be deemed unreachable .

Bellman - Ford Algorithm

RIP When transmitting route entry information , Just pass two parameters ：1. Target network segment information 2. Cost value cost, There is no need to pass the rest , Because that information depends on Behrman - Calculated by Ford algorithm .

behrman - According to different situations, Ford algorithm has the following four different processing methods , as follows ：

1、R2 take 2.0 The routing information of the network segment is sent to R1, however ,R1 Local did not arrive 2.0 network Routing information of segment . be R1 take

The routing information is refreshed to the local routing table .

2、R2 take 2.0 The routing information of the network segment is sent to R1, however ,R1 Local presence arrives 2.0 Routing information of network segment , also , Next jump

It's also R2. be R1 take R2 The routing information sent is refreshed to the local routing table .

3、R2 take 2.0 The routing information of the network segment is sent to R1, however ,R1 Local presence arrives 2.0 Routing information of network segment , also , Next jump

No R2. Then compare the cost value , If , The local cost value is greater than R2 The cost value sent , be R1 take R2 Send the refresh to the local

In the routing table of .

4、R2 take 2.0 The routing information of the network segment is sent to R1, however ,R1 Local presence arrives 2.0 Routing information of network segment , also , Next jump

No R2. Then compare the cost value , If , The local cost value is less than R2 The cost value sent , be R1 Will not refresh .

Be careful ：RIP The default priority for is 100

RIP Version of

RIP There are three versions , Namely RIPV1（IPV4）、RIPV2（IPV4）、RIPNG（IPV6）

RIPV1 and RIPV2 The difference between ：

1、RIPV1 There are categories of routing protocols ,RIPV2 Classless Routing Protocol

2、RIPV1 Manual authentication is not supported ,RIPV2 Support manual authentication

3、RIPV1 It transmits routing information in the form of broadcast , and RIPV2 It transmits routing information in the form of multicast .

RIP Basic configuration

1, start-up RIP process

[r1]rip 1

[r1-rip-1]

2, Choose the version

[r1-rip-1]version 2

3, Declare

requirement ：1, All direct network segments need to declare ;2, Must be declared according to the main class

[r1-rip-1]network 1.0.0.0

effect ：1, Activate interface ; --- Only the active interface can send and receive RIP The data of

           2, Publish route ; --- Only the routing information of the direct network segment corresponding to the activated interface can be published

Silent interface --- Interfaces configured as silent interfaces will only accept not send RIP Data packets of .

[r1-rip-1]silent-interface GigabitEthernet 0/0/2

RIPV1 and RIPV2 The packet structure of --- A packet can carry at most 25 Routes

entry , If certification exists , It will occupy the space of a route entry , Then he will only be able to carry

belt 24 Route entries .

COMMAND --- Mark the RIP The type of packet

1 --- request

2 --- response

Version --- Mark the RIP Version of protocol

1 --- RIPV1

2 --- RIPV2

Routing entry information

Address family identifier --- 2 --- IP Address family

Target network segment information

Cost value

RIPV2 Unique to

Routing tags --- Add a tag on the route entry , Facilitate the capture of subsequent traffic . The default flag is 0.

Mask information

Next jump --- Mainly to deal with the scene of poor route selection , When there is a scene of poor route selection , You can write the most in the next hop field

Jia's next jump , Instead of using the algorithm to calculate the next hop . If it's normal , Then the next hop field uses 0.0.0.0 fill .

Because the operation mechanism of different routing protocols is different , And the understanding of routing is also different , therefore , Between different routing protocols

There is information isolation . therefore , We need to be on the boundary equipment of the agreement （ Run both protocols at the same time ） Perform republishing --- Give Way

The router sends one routing protocol according to the rules of another routing protocol .

[r4-rip-1]import-route static

[r3-GigabitEthernet0/0/0]rip version 2 --- Configure... On the interface , Let the interface send and receive according to the rules of the corresponding version RIP Of

data , Realization RIPV1 and RIPV2 Version compatibility .