RIP configuration perfection strategy

You may be familiar with the RIP Protocol. This Protocol is widely used. This Protocol is applied in many networks. If you do not have RIP configuration, you don't have to worry about it. Next we will explain the configuration process in detail, so that everyone can learn it.

IP Address Configuration

You can use the interface command to enter the local configuration mode, and then use ip address to set the ip address of the interface, as shown below.

 
 

  
  
testBJ#conf　t  
  
  
Enter　configuration　commands,　one　per　line.　End　with　CNTL/Z.  
  
  
testBJ(config)#interface　e0/1  
  
  
testBJ(config-if)#ip　address　172.16.1.2　255.255.255.0  
  
  
testBJ(config-if)# 
 
 

To facilitate configuration and memory, you can also add descriptions for each port as follows. Use the description command in local port configuration mode.

 
 

  
  
testBJ(config-if)#description　connect　to　testSH  
  
  
testBJ(config-if)#end  
  
  
testBJ# 
 
 

Some networks are NBMANon-Broadcast MultiAccess and non-Broadcast multi-channel access), that is, Broadcast is not allowed to transmit data on the network. for such a network, RIP cannot rely on the broadcast route table. there are many solutions, the simplest is to specify the neighbor), that is, specify to send the route table to a specific router.

RIP Configuration

RIP configuration is the easiest. You only need two steps to configure it. First, specify the RIP Protocol and then declare the connected network number, as shown below.

 
 

  
  
testBJ(config)#router　rip  
  
  
testBJ(config-router)#network　172.16.0.0  
  
  
testBJ(config-router)#end  
  
  
testBJ# 
 
 

The router rip command is used to specify the RIP Protocol. The network command declares the network number. Because RIP is a classless routing protocol, you do not need to declare the subnet numbers. repeat the preceding operations on each vro to create a network using the RIP route.

Test the RIP configuration correctness.

After RIP is configured, check whether the data can be correctly routed. In addition to using the connectivity test tool mentioned above, there are also the following commands:

Sh ip route is used to detect the route table;

Sh ip protocols is used to check the routing protocol status;

Debug ip rip is used to debug RIP Protocol information.

Use the sh ip route command to display the route tables of each vro.

 
 

  
  
testBJ#sh　ip　route  
  
  
Codes:　C　-　connected,　S　-　static,　I　-　IGRP,　R　-　RIP,　M　-　mobile,　B　-　BGP  
  
  
D　-　EIGRP,　EX　-　EIGRP　external,　O　-　OSPF,　IA　-　OSPF　inter　area  
  
  
N1　-　OSPF　NSSA　external　type　1,　N2　-　OSPF　NSSA　external　type　2  
  
  
E1　-　OSPF　external　type　1,　E2　-　OSPF　external　type　2,　E　-　EGP  
  
  
i　-　IS-IS,　L1　-　IS-IS　level-1,　L2　-　IS-IS　level-2,  
  
  
*　-　candidate　default,　U　-　per-user　static　route,　o　-　ODR  
  
  
Gateway　of　last　resort　is　not　set  
  
  
172.16.0.0/24　is　subnetted,　4　subnets  
  
  
R　172.16.4.0　[120/1]　via　172.16.2.2,　00:00:12,　Serial1/0  
  
  
C　172.16.1.0　is　directly　connected,　Ethernet0/1  
  
  
C　172.16.2.0　is　directly　connected,　Serial1/0  
  
  
R　172.16.3.0　[120/1]　via　172.16.1.3,　00:00:09,　Ethernet0/1  
  
  
[120/1]　via　172.16.2.2,　00:00:22,　Serial1/0 
 
 

The preceding figure shows the route information of the Beijing router. the English letter C starts with a directly connected network, with 172.16.1.0 and 172.16.2.0 connected to e0/1 and s1/0 respectively. the English letter R starts with the Routes learned by the RIP Protocol. There are 172.16.3.0 and 172.16.4.0, and there are two paths to 172.16.3.0 for selection, respectively through testSH and testTJ routers. by comparing the network topology, we can see that the actual situation is exactly the same as the design. the content in the brackets is the Management Distance and measurement value of the route item. The default Management Distance of the RIP configuration is 120, and the measurement value to reach the 3 and 4 subnets is 1, that is, it can be reached through one vro. run the same command on the other two routers. The result is as follows.

 
 

  
  
testSH#sh　ip　route  
  
  
Gateway　of　last　resort　is　not　set  
  
  
172.16.0.0/24　is　subnetted,　4　subnets  
  
  
R　172.16.4.0　[120/1]　via　172.16.3.2,　00:00:13,　Ethernet0/0  
  
  
C　172.16.1.0　is　directly　connected,　Ethernet0/1  
  
  
R　172.16.2.0　[120/1]　via　172.16.1.2,　00:00:11,　Ethernet0/1  
  
  
[120/1]　via　172.16.3.2,　00:00:13,　Ethernet0/0  
  
  
C　172.16.3.0　is　directly　connected,　Ethernet0/0  
  
  
testTJ#sh　ip　route  
  
  
Gateway　of　last　resort　is　not　set  
  
  
172.16.0.0/24　is　subnetted,　4　subnets  
  
  
C　172.16.4.0　is　directly　connected,　Ethernet0/0  
  
  
R　172.16.1.0　[120/1]　via　172.16.3.3,　00:00:07,　Ethernet0/1  
  
  
[120/1]　via　172.16.2.3,　00:00:19,　Serial1/0  
  
  
C　172.16.2.0　is　directly　connected,　Serial1/0  
  
  
C　172.16.3.0　is　directly　connected,　Ethernet0/1 
 
 

When analyzing the above command output, make sure to refer to the topology at any time and leave the network topology, the above information does not make any sense. the flexibility of dynamic routing is reflected in the failure of a link, and the routing algorithm automatically switches to the loose link. for example, we disconnect the serial cable between testBJ and testTJ. After a while, check the route table, as shown below.

 
 

  
  
testBJ#sh　ip　route  
  
  
Gateway　of　last　resort　is　not　set  
  
  
172.16.0.0/24　is　subnetted,　3　subnets  
  
  
R　172.16.4.0　[120/2]　via　172.16.1.3,　00:00:22,　Ethernet0/1  
  
  
C　172.16.1.0　is　directly　connected,　Ethernet0/1  
  
  
R　172.16.3.0　[120/1]　via　172.16.1.3,　00:00:22,　Ethernet0/1 
 
 

We found that subnet 2 of the serial link is disconnected, and all data packets destined for network 172.16.4.0 will go through the testSH router.

THE sh ip protocols command displays the status of the current routing protocol, as shown below.

 
 

  
  
testBJ#sh　ip　protocols  
  
  
Routing　Protocol　is　"rip"  
  
  
Sending　updates　every　30　seconds,　next　due　in　19　seconds  
  
  
Invalid　after　180　seconds,　hold　down　180,　flushed　after　240  
  
  
Outgoing　update　filter　list　for　all　interfaces　is　not　set  
  
  
Incoming　update　filter　list　for　all　interfaces　is　not　set  
  
  
Redistributing:　connected,　rip  
  
  
Default　version　control:　send　version　1,　receive　any　version  
  
  
Interface　Send　Recv　Key-chain  
  
  
Ethernet0/1　1　1　2  
  
  
Serial1/0　1　1　2  
  
  
Routing　for　Networks:  
  
  
172.16.0.0  
  
  
Routing　Information　Sources:  
  
  
Gateway　Distance　Last　Update  
  
  
172.16.2.2　120　00:00:05  
  
  
172.16.1.3　120　00:00:27  
  
  
Distance:　(default　is　120) 
 
 

From the command output, we can see the RIP configuration. We can also find that the routers that exchange information with the current vro are testTJ172.16.2.2) and testSH172.16.1.3, the route information received last time is 5 seconds and 27 seconds ago, respectively. to learn more about route information exchange between routers, run the debug ip rip command. as shown in the following figure, after you enter the command, information about receiving or sending RIP broadcasts appears on the console.

 
 

  
  
testBJ#debug　ip　rip  
  
  
RIP　protocol　debugging　is　on  
  
  
testBJ#  
  
  
RIP:　received　v1　update　from　172.16.2.2　on　Serial1/0  
  
  
172.16.4.0　in　1　hops  
  
  
172.16.3.0　in　1　hops  
  
  
RIP:　received　v1　update　from　172.16.1.3　on　Ethernet0/1  
  
  
172.16.4.0　in　2　hops  
  
  
172.16.3.0　in　1　hops  
  
  
RIP:　sending　v1　update　to　255.255.255.255　via　Ethernet0/1　(172.16.1.2)  
  
  
subnet　172.16.4.0,　metric　2  
  
  
subnet　172.16.2.0,　metric  
  
  
RIP:　sending　v1　update　to　255.255.255.255　via　Serial1/0　(172.16.2.3)  
  
  
subnet　172.16.1.0,　metric　1  
  
  
RIP:　received　v1　update　from　172.16.1.3　on　Ethernet0/1  
  
  
172.16.4.0　in　2　hops  
  
  
172.16.3.0　in　1　hops  
  
  
RIP:　received　v1　update　from　172.16.2.2　on　Serial1/0  
  
  
172.16.4.0　in　1　hops  
  
  
172.16.3.0　in　1　hops  
  
  
testBJ#no　debug　all  
  
  
All　possible　debugging　has　been　turned　off  
  
  
testBJ# 
 
 

You can obtain the details of the RIP broadcast from the above RIP configuration information. the router first receives the information about subnet 3 and subnet 4 from testTJ, and then receives the information about subnet 3 and subnet 4 from testSH. here, the testTJ hop is taken to subnet 4 and the testSH hop is taken. Therefore, the routing table shows that the distance from testTJ to subnet 4 is a hop, so, there are two parallel routes in the route table. after a period of time, the current update time of the router reaches 30 seconds. Therefore, it broadcasts its route table information on two links. note: When a broadcast route is updated, RIP uses a horizontal split mechanism. The information learned from a port is not broadcast on this port, therefore, the current vrotesttestbj only sends route information for the subnet 172.16.1.0. use the no debug all command to end the display of debugging information. note that the debug command consumes vro resources, so do not use it on a busy communication router. Otherwise, the router will stop responding like a dead machine.