How to Configure RIPv1 – Cisco (Free Preview)

This is a preview lesson. Please purchase the course to access all lessons.

In this lesson, we are going to configure a very basic RIP process on three Cisco 1841 routers and verify our configuration. Our configuration will be based on the following network design.

 

Figure Network Diagram

 

Network Interface Connections

Device Interface IPv4 Address Device Interface IPv4 Address
R1 F0/0 192.168.10.1/24 PC Y NIC0 192.168.10.10/24
R1 F0/1 192.168.20.1/24 R2 F0/0 192.168.20.2/24
R2 F0/0 192.168.20.2/24 R1 F0/1 192.168.20.1/24
R2 F0/1 192.168.30.2/24 R3 F0/1 192.168.30.3/24
R3 F0/0 192.168.40.3/24 PC X NIC0 192.168.40.10/24
R3 F0/1 192.168.30.3/24 R2 F0/1 192.168.30.2/24

 

SUMMARY STEPS

  1. enable

!— Enters the Privileged EXEC mode —!

  1. configure terminal

!— Enters global configuration mode. —!

  1. router rip

!— Enables a RIP routing process and enters router configuration mode —!

  1. network ip-address

!— Associates a network interface with a RIP routing process. —!

  1. end

!— Exits router configuration mode and returns to privileged EXEC mode. —!

Let’s look at the pre-change configuration

R1#show version
Cisco IOS Software, 1841 Software (C1841-ADVIPSERVICESK9-M), Version 15.1(4)M1, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2011 by Cisco Systems, Inc.
Compiled Tue 14-Jun-11 16:51 by prod_rel_team

ROM: System Bootstrap, Version 12.4(13r)T, RELEASE SOFTWARE (fc1)

R1 uptime is 27 minutes
System returned to ROM by power-on
System image file is "flash:c1841-advipservicesk9-mz.151-4.M1.bin"
Last reload type: Normal Reload


This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to
export@cisco.com.

Cisco 1841 (revision 7.0) with 239616K/22528K bytes of memory.
Processor board ID FHK1232273Y
2 FastEthernet interfaces
1 Virtual Private Network (VPN) Module
DRAM configuration is 64 bits wide with parity disabled.
191K bytes of NVRAM.
62720K bytes of ATA CompactFlash (Read/Write)


License Info:

License UDI:

-------------------------------------------------
Device#	  PID			SN
-------------------------------------------------
*0  	  CISCO1841             FHK1232273Y     



Configuration register is 0x2102

R1#show ip interface brief
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0/0            192.168.10.1    YES NVRAM  up                    up      
FastEthernet0/1            192.168.20.1    YES NVRAM  up                    up      
!--- Lists the R1 interface configuration information ---!
R1#show ip protocols
*** IP Routing is NSF aware ***

!--- Lists the routing protocol information. Since we have not configured a routing protocol we can see it is empty ---!


R1#show ip route
Codes: L - local, C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is not set

      192.168.10.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.10.0/24 is directly connected, FastEthernet0/0
L        192.168.10.1/32 is directly connected, FastEthernet0/0
      192.168.20.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.20.0/24 is directly connected, FastEthernet0/1
L        192.168.20.1/32 is directly connected, FastEthernet0/1
!--- Routing table of R1 lists the directly connected interfaces ---!
R2#show version
Cisco IOS Software, 1841 Software (C1841-ADVIPSERVICESK9-M), Version 15.1(4)M1, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2011 by Cisco Systems, Inc.
Compiled Tue 14-Jun-11 16:51 by prod_rel_team

ROM: System Bootstrap, Version 12.4(13r)T, RELEASE SOFTWARE (fc1)

R2 uptime is 23 minutes
System returned to ROM by power-on
System image file is "flash:c1841-advipservicesk9-mz.151-4.M1.bin"
Last reload type: Normal Reload


This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to
export@cisco.com.

Cisco 1841 (revision 7.0) with 239616K/22528K bytes of memory.
Processor board ID FHK1234275K
2 FastEthernet interfaces
1 Virtual Private Network (VPN) Module
DRAM configuration is 64 bits wide with parity disabled.
191K bytes of NVRAM.
62720K bytes of ATA CompactFlash (Read/Write)


License Info:

License UDI:

-------------------------------------------------
Device#	  PID			SN
-------------------------------------------------
*0  	  CISCO1841             FHK1234275K     



Configuration register is 0x2102



R2#show ip interface brief
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0/0            192.168.20.2    YES NVRAM  up                    up      
FastEthernet0/1            192.168.30.2    YES NVRAM  up                    up      
R2#show ip protocols
*** IP Routing is NSF aware ***



R2#show ip interface brief
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0/0            192.168.20.2    YES NVRAM  up                    up      
FastEthernet0/1            192.168.30.2    YES NVRAM  up                    up      


R2#show ip protocols
*** IP Routing is NSF aware ***



R2#show ip route
Codes: L - local, C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is not set

      192.168.20.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.20.0/24 is directly connected, FastEthernet0/0
L        192.168.20.2/32 is directly connected, FastEthernet0/0
      192.168.30.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.30.0/24 is directly connected, FastEthernet0/1
L        192.168.30.2/32 is directly connected, FastEthernet0/1
R3#show version
Cisco IOS Software, 1841 Software (C1841-ADVIPSERVICESK9-M), Version 15.1(4)M1, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2011 by Cisco Systems, Inc.
Compiled Tue 14-Jun-11 16:51 by prod_rel_team

ROM: System Bootstrap, Version 12.4(13r)T, RELEASE SOFTWARE (fc1)

R3 uptime is 29 minutes
System returned to ROM by power-on
System image file is "flash:c1841-advipservicesk9-mz.151-4.M1.bin"
Last reload type: Normal Reload


This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to
export@cisco.com.

Cisco 1841 (revision 7.0) with 239616K/22528K bytes of memory.
Processor board ID FHK132773LJ
2 FastEthernet interfaces
1 Virtual Private Network (VPN) Module
DRAM configuration is 64 bits wide with parity disabled.
191K bytes of NVRAM.
62720K bytes of ATA CompactFlash (Read/Write)


License Info:

License UDI:

-------------------------------------------------
Device#	  PID			SN
-------------------------------------------------
*0  	  CISCO1841             FHK132773LJ     



Configuration register is 0x2102


R3#show ip interface brief
Interface                  IP-Address      OK? Method Status                Protocol
FastEthernet0/0            192.168.40.3    YES NVRAM  up                    up      
FastEthernet0/1            192.168.30.3    YES NVRAM  up                    up      
R3#show ip protocols
*** IP Routing is NSF aware ***


R3#show ip route
Codes: L - local, C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is not set

      192.168.30.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.30.0/24 is directly connected, FastEthernet0/1
L        192.168.30.3/32 is directly connected, FastEthernet0/1
      192.168.40.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.40.0/24 is directly connected, FastEthernet0/0
L        192.168.40.3/32 is directly connected, FastEthernet0/0

We can see that our routers know only about there directly connected interfaces.

R1 Configuration

Firstly, let’s configure R1

R1#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
R1(config)#router ?
  bgp       Border Gateway Protocol (BGP)
  eigrp     Enhanced Interior Gateway Routing Protocol (EIGRP)
  isis      ISO IS-IS
  iso-igrp  IGRP for OSI networks
  lisp      Locator/ID Separation Protocol
  mobile    Mobile routes
  odr       On Demand stub Routes
  ospf      Open Shortest Path First (OSPF)
  rip       Routing Information Protocol (RIP)

R1(config)#router rip
!--- Enables a RIP routing process and enters router configuration mode. By default RIPv1 is enabled. ---!
R1(config-router)#?
Router configuration commands:
  address-family          Enter Address Family command mode
  auto-summary            Enable automatic network number summarization
  default                 Set a command to its defaults
  default-information     Control distribution of default information
  default-metric          Set metric of redistributed routes
  distance                Define an administrative distance
  distribute-list         Filter networks in routing updates
  exit                    Exit from routing protocol configuration mode
  flash-update-threshold  Specify flash update threshold in second
  help                    Description of the interactive help system
  input-queue             Specify input queue depth
  maximum-paths           Forward packets over multiple paths
  neighbor                Specify a neighbor router
  network                 Enable routing on an IP network
  no                      Negate a command or set its defaults
  offset-list             Add or subtract offset from RIP metrics
  output-delay            Interpacket delay for RIP updates
  passive-interface       Suppress routing updates on an interface
  redistribute            Redistribute information from another routing
                          protocol
  timers                  Adjust routing timers
  traffic-share           How to compute traffic share over alternate paths
  validate-update-source  Perform sanity checks against source address of
                          routing updates
  version                 Set routing protocol version

R1(config-router)#network 192.168.10.0
!--- Associates interface 192.168.10.1 with the RIP routing process. ---!

R1(config-router)#network 192.168.20.0
!--- Associates interface 192.168.20.1 with the RIP routing process. ---!

R1(config-router)#exit
R1(config)#^Z
R1#

 

The network statement

Remember the network statements are meant to identify which interfaces will participate in the Routing Protocol Process. It does not identify which networks to advertise rather which interfaces should participate in routing protocols process. So always think interfaces.

For example the network statement network 192.168.20.0 informs the RIP Routing Process to include any interface that falls in the range of 192.168.20.0 /24. Since RIP is a classful routing protocol it will apply the default major network prefix-length to the configured network address and will include all interfaces within that range.

 

Now let’s have a look at the show ip protocols and show ip route commands to see what has changed on R1.

R1#show ip protocols
*** IP Routing is NSF aware ***

Routing Protocol is "rip"
!--- We can see that RIP is active on the router ---!
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Sending updates every 30 seconds, next due in 17 seconds
!--- The time between routing updates ---!
  Invalid after 180 seconds, hold down 180, flushed after 240
!--- The timer vales for invalid, hold-down and flushed ---!
  Redistributing: rip
  Default version control: send version 1, receive any version
!--- By default RIP only sends RIPv1 updates. However it receives RIPv1 & RIPv2 ---! 
    Interface             Send  Recv  Triggered RIP  Key-chain
    FastEthernet0/0       1     1 2                                  
    FastEthernet0/1       1     1 2  
!--- By default RIP only sends RIPv1 updates. However it receives RIPv1 & RIPv2 ---!                                
  Automatic network summarization is in effect
!--- By default automatic network summarization is enabled ---!
  Maximum path: 4
  Routing for Networks:
    192.168.10.0
    192.168.20.0
!--- Networks for which the routing process is currently injecting routes ---!
  Routing Information Sources:
    Gateway         Distance      Last Update

!--- Lists all the routing sources that the Cisco IOS software is using to build its routing table ---!
  Distance: (default is 120)
!--- Lists the Administrative Distance ---!


R1#show ip protocols | section Default
  Default version control: send version 1, receive any version
    Interface             Send  Recv  Triggered RIP  Key-chain
    FastEthernet0/0       1     1 2                                  
    FastEthernet0/1       1     1 2                                  


R1#show ip route
Codes: L - local, C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is not set

      192.168.10.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.10.0/24 is directly connected, FastEthernet0/0
L        192.168.10.1/32 is directly connected, FastEthernet0/0
      192.168.20.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.20.0/24 is directly connected, FastEthernet0/1
L        192.168.20.1/32 is directly connected, FastEthernet0/1
!--- The routing table still lists only the connected interfaces. The reason being is we have not discovered any RIP neighbors because we have not configured RIP on any other router ---!

R2 Configuration

R2#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
R2(config)#router rip
R2(config-router)#network 192.168.20.0
R2(config-router)#network 192.168.30.0
R2(config-router)#end
R2#
*Jan  1 08:12:41.107: %SYS-5-CONFIG_I: Configured from console by console
!--- End of R2 Configuration ---!

R2#show ip protocols
*** IP Routing is NSF aware ***

Routing Protocol is "rip"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Sending updates every 30 seconds, next due in 0 seconds
  Invalid after 180 seconds, hold down 180, flushed after 240
  Redistributing: rip
  Default version control: send version 1, receive any version
    Interface             Send  Recv  Triggered RIP  Key-chain
    FastEthernet0/0       1     1 2                                  
    FastEthernet0/1       1     1 2                                  
  Automatic network summarization is in effect
  Maximum path: 4
  Routing for Networks:
    192.168.20.0
    192.168.30.0
  Routing Information Sources:
    Gateway         Distance      Last Update
    192.168.20.1         120      00:00:14
  Distance: (default is 120)
!--- We can see  R2 is learning routing updates from R1 ---!


R2#show ip protocols | section Defaults 
  Default version control: send version 1, receive any version
    Interface             Send  Recv  Triggered RIP  Key-chain
    FastEthernet0/0       1     1 2                                  
    FastEthernet0/1       1     1 2                                  


R2#show ip route
Codes: L - local, C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is not set

R     192.168.10.0/24 [120/1] via 192.168.20.1, 00:00:00, FastEthernet0/0
      192.168.20.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.20.0/24 is directly connected, FastEthernet0/0
L        192.168.20.2/32 is directly connected, FastEthernet0/0
      192.168.30.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.30.0/24 is directly connected, FastEthernet0/1
L        192.168.30.2/32 is directly connected, FastEthernet0/1
!--- R2 has learned about network 192.168.10.0 from R1 ---!

 

Let’s jump to R1 and see whether R1 has learned any routes from R2

R1#show ip route
Codes: L - local, C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is not set

      192.168.10.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.10.0/24 is directly connected, FastEthernet0/0
L        192.168.10.1/32 is directly connected, FastEthernet0/0
      192.168.20.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.20.0/24 is directly connected, FastEthernet0/1
L        192.168.20.1/32 is directly connected, FastEthernet0/1
R     192.168.30.0/24 [120/1] via 192.168.20.2, 00:00:12, FastEthernet0/1
!--- R1 has learned a dynamic route from R2 ---!

 

R3 Configuration

R3#configure terminal
Enter configuration commands, one per line.  End with CNTL/Z.
R3(config)#router rip
R3(config-router)#network 192.168.30.0
R3(config-router)#network 192.168.40.0
R3(config-router)#end
R3#

 

Verification on R3

R3#show ip protocols
*** IP Routing is NSF aware ***

Routing Protocol is "rip"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Sending updates every 30 seconds, next due in 0 seconds
  Invalid after 180 seconds, hold down 180, flushed after 240
  Redistributing: rip
  Default version control: send version 1, receive any version
    Interface             Send  Recv  Triggered RIP  Key-chain
    FastEthernet0/0       1     1 2                                  
    FastEthernet0/1       1     1 2                                  
  Automatic network summarization is in effect
  Maximum path: 4
  Routing for Networks:
    192.168.30.0
    192.168.40.0
  Routing Information Sources:
    Gateway         Distance      Last Update
    192.168.30.2         120      00:00:07
  Distance: (default is 120)
!--- R3 is learning routes from R2 ---!


R3#show ip protocols | section Default
  Default version control: send version 1, receive any version
    Interface             Send  Recv  Triggered RIP  Key-chain
    FastEthernet0/0       1     1 2                                  
    FastEthernet0/1       1     1 2                                  


R3#show ip route
Codes: L - local, C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is not set

R     192.168.10.0/24 [120/2] via 192.168.30.2, 00:00:18, FastEthernet0/1
R     192.168.20.0/24 [120/1] via 192.168.30.2, 00:00:18, FastEthernet0/1
      192.168.30.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.30.0/24 is directly connected, FastEthernet0/1
L        192.168.30.3/32 is directly connected, FastEthernet0/1
      192.168.40.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.40.0/24 is directly connected, FastEthernet0/0
L        192.168.40.3/32 is directly connected, FastEthernet0/0
!--- R3 has learned about 192.168.10.0 & 192.168.20.0 from R2 ---!

 

Looks good. Lets jump to R2 & R1 and see whether they are learning routes from R3

 

Verification on R2

 

R2#show ip protocols
*** IP Routing is NSF aware ***

Routing Protocol is "rip"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Sending updates every 30 seconds, next due in 11 seconds
  Invalid after 180 seconds, hold down 180, flushed after 240
  Redistributing: rip
  Default version control: send version 1, receive any version
    Interface             Send  Recv  Triggered RIP  Key-chain
    FastEthernet0/0       1     1 2                                  
    FastEthernet0/1       1     1 2                                  
  Automatic network summarization is in effect
  Maximum path: 4
  Routing for Networks:
    192.168.20.0
    192.168.30.0
  Routing Information Sources:
    Gateway         Distance      Last Update
    192.168.30.3         120      00:00:03
    192.168.20.1         120      00:00:22
  Distance: (default is 120)
!--- R2 is learning routes from R1 & R3 ---!


R2#show ip route
Codes: L - local, C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is not set

R     192.168.10.0/24 [120/1] via 192.168.20.1, 00:00:09, FastEthernet0/0
      192.168.20.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.20.0/24 is directly connected, FastEthernet0/0
L        192.168.20.2/32 is directly connected, FastEthernet0/0
      192.168.30.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.30.0/24 is directly connected, FastEthernet0/1
L        192.168.30.2/32 is directly connected, FastEthernet0/1
R     192.168.40.0/24 [120/1] via 192.168.30.3, 00:00:21, FastEthernet0/1
!--- R2 is learning route 192.168.10.0 from R1 and 192.168.40.0 from R3 ---!

 

Verification on R1

R1#show ip route
Codes: L - local, C - connected, S - static, 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
       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
       ia - IS-IS inter area, * - candidate default, U - per-user static route
       o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
       + - replicated route, % - next hop override

Gateway of last resort is not set

      192.168.10.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.10.0/24 is directly connected, FastEthernet0/0
L        192.168.10.1/32 is directly connected, FastEthernet0/0
      192.168.20.0/24 is variably subnetted, 2 subnets, 2 masks
C        192.168.20.0/24 is directly connected, FastEthernet0/1
L        192.168.20.1/32 is directly connected, FastEthernet0/1
R     192.168.30.0/24 [120/1] via 192.168.20.2, 00:00:01, FastEthernet0/1
R     192.168.40.0/24 [120/2] via 192.168.20.2, 00:00:01, FastEthernet0/1
!--- R1 is also learning two routes. 192.168.30.0 & 192.168.40.0 from R2 ---!

RIP Metric

  • Uses hop count as the only metric.
  • Each hop in the path is assigned a value of 1. When a routing advertisement is received for a destination network, the router adds 1 to the metric value specified in the advertisement and specifies the sender as the next-hop.
  • A directly connected network metric = 0
  • Unreachable network metric = 16

 

Let’s examine

R     192.168.40.0/24 [120/2] via 192.168.20.2, 00:00:01, FastEthernet0/1

 

  1. “R” signifies this is a RIP route.
  2. “192.168.40.0/24” identifies the destination network.
  3. [120/2] signifies the RIP administrative distance.
  4. Then [120/2] states the network 192.168.40.0/24 is 2 hops away from R1.
  5. The next-hop to reach the network is R2(192.168.20.2).
  6. Finally, the egress interface to reach the next-hop is FastEthernet0/1.

 

 RIP Timers

  1. Route update timer (30s): Updates are sent every 30 seconds and when there are topology changes.
  2. Invalid after timer (180s): Length of time that must pass before concluding a route is invalid
  3. Hold Down timer (180s): If a router doesn’t receive an update from another neighboring router within the Hold Down time period or more, the receiving router marks all routes from the neighboring router as unusable.
  4. Flushed after timer (240s): If there is still no update after 240 seconds, the receiving router removes all routing table entries for the neighboring router that failed to send an update.

 

R1#show ip protocols
*** IP Routing is NSF aware ***

Routing Protocol is "rip"

  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Sending updates every 30 seconds, next due in 17 seconds
!--- The time between routing updates ---!
  Invalid after 180 seconds, hold down 180, flushed after 240
!--- The timer vales for invalid, hold-down and flushed ---!
  Redistributing: rip
  Default version control: send version 1, receive any version

 

 

 

Finally, we should have end to end reachability. Let’s test it.

R1#ping 192.168.40.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.40.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms


R1#ping 192.168.40.10
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.40.10, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms

 

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