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Configuring IGRP Routing protocol on the router

Configuring IGRP Routing protocol on the router

IGRP (Interior Gateway Routing Protocol)

Routers communicate with each other by using the routing protocol.
One of the routing protocol is IGRP
It is desirable to distinguish Routed and Routing protocols.

Router is arranged between the state of the network, exchange information:
- Exchange information on the network you are on line,
- Exchange information on the network that is active
- etc.

IGRP is also a Distance Vector Routing Protocols, as well as RIPv1, which is researched by Cisco company.
Unlike RIPv1 (update every 30 seconds), IGRP sends update their routing tables every 90 seconds.

Features IGRP Routing Protocols:

- Classful routing protocol (meaning that does not support VLSM, for support VLSM Cisco has defined EIGRP)
- Update every 90 sec. by default
- There is no difference between internal and external routes
- Maximum Hop Count =255
- By default, IGRP uses Bandwidth and Delay (delay) as a metric.
- Administrative distance is 100 by default

The main design characteristics of IGRP-are as follows:

- The possibility automataskog handling infinite and complex topologies
- The flexibility needed for segmentation with different bandwidth
- Possibility to use in very large networks

IGRP uses the following elements of the metrics:

- Bandwidth - The lowest bandwidth value in the path
- Delay - The cumulative interface delay along the path
- Reliability - The reliability on the link toward the destination as determined by the exchange of keepalives
- Load - The load on a link toward the destination based on bits per second

There are three types of routes that IGRP can advertise (advertise)

- Interior  Advertising
- System  Advertising
- Exterior  Advertising

Interior Routing Protocol (IGP)
- IGP (Interior Gateway Protocol) functions within a single Autonomous System (AS)

Exterior Routing protocol
BGP (Border Gateway Protocol)

Key features of BGP are as follows:

- Distance vector routing protocol exterior
- Use between 'ISP-ISP' or 'ISP-Client'
- Is used between autonomous systems (AS)

For the stability of the IGRP routing protocols are important three features:

- Hold down
- Split horizons
- Poison reverse updates

It is important to remember these three tables bellow

Figure 1.
IGP, EGP and Distance Vector or Link State

Figure 1a.

Administrative distance on the Cisco Router

An example of a network where it can be used IGRP routing protocol.
What is Autonomous System (AS)? In layman can say that the network is under joint administration.
On the Figure2 you may see the RIP and OSPF routing protocols. When configuring IGRP and EIGRP require a number of AS, OSPF claim number process (process ID), the RIP protocol demands the not even one.

Figure 2.

View scheme Autonomus System (AS) in the IT Network

Configure IGRP routing protocol on the router

Figure 3.

View scheme configuring IGRP protocol between two routers

Router Vinkovci-1

  Router>
  Router # configure terminal
  Router (config) #hostname Vinkovci-1
  Vinkovci-1 (config) #banner motd #Welcome to Router Vinkovci-1#

  Vinkovci-1 (config) #line console 0
  Vinkovci-1 (config-line) #Password cisco
  Vinkovci-1 (config-line) #login
  Vinkovci-1 (config-line) #Exit

  Vinkovci-1 (config) #line vty 0 4
  Vinkovci-1 (config-line) #Password cisco
  Vinkovci-1 (config-line) #login
  Vinkovci-1 (config-line) #Exit

  Vinkovci-1 (config) #enable password cisco
  Vinkovci-1 (config) #enable secret class

  Vinkovci-1 (config) #ip host Vinkovci-2 192.168.0.2

  Vinkovci-1 (config) #interface serial 1
  Vinkovci-1 (config-if) #ip address 192.168.0.1 255.255.255.0
  Vinkovci-1 (config-if) #clock rate 64000 //setting Interface Router for DCE signal
  Vinkovci-1 (config-if) #No shutdown
  Vinkovci-1 (config-if) #description Serial connections to Vinkovci-2
  Vinkovci-1 (config-if) #Exit

  Vinkovci-1 (config) #interface FastEthernet 0
  Vinkovci-1 (config-if) #ip address 192.168.4.1 255.255.255.0
  Vinkovci-1 (config-if) #No shutdown
  Vinkovci-1 (config-if) #description LAN Network
  Vinkovci-1 (config-if) #Exit
  Vinkovci-1 (config) #Exit
  Vinkovci-1 # copy running-config startup-config


Router Vinkovci-2

  Router>
  Router> enable
  Router # configure terminal
  Router (config) #hostname Vinkovci-2

  Vinkovci-2 (config) #banner motd #Welcome to Router Vinkovci-2#

  Vinkovci-2 (config) #line console 0
  Vinkovci-2 (config-line) #Password cisco
  Vinkovci-2 (config-line) #login
  Vinkovci-2 (config-line) #Exit

  Vinkovci-2 (config) #line vty 0 4
  Vinkovci-2 (config-line) #Password cisco
  Vinkovci-2 (config-line) #login
  Vinkovci-2 (config-line) #Exit

  Vinkovci-2 (config) #enable password cisco
  Vinkovci-2 (config) #enable secret class

  Vinkovci-2 (config) #ip host Vinkovci-1 192.168.0.1

  Vinkovci-2 (config) #interface serial 0
  Vinkovci-2 (config-if) #ip address 192.168.0.2 255.255.255.0
  Vinkovci-2 (config-if) #No shutdown
  Vinkovci-2 (config-if) #description Serial connections to Vinkovci-1
  Vinkovci-2 (config-if) #Exit

  Vinkovci-2 (config) #interface FastEthernet 0
  Vinkovci-2 (config-if) #ip address 192.168.5.1 255.255.255.0
  Vinkovci-2 (config-if) #No shutdown
  Vinkovci-2 (config-if) #description LAN connection
  Vinkovci-2 (config-if) #Exit
  Vinkovci-2 (config) #Exit
  Vinkovci 2 # copy running-config startup-config


Now we set the basic configuration on both routers. To these routers can communicate with each other and create their routing tables need to configure a routing protocol. We will be able to configure IGRP routing protocol

Configure IGRP routing protocol on the Vinkovci-1 Router

Vinkovci-1 # configure terminal
Vinkovci-1 (config) #router igrp 100 // set the IGRP routing protocol with AS 100
Vinkovci-1 (config-router) #network 192.168.4.0 // Advertising Network
Vinkovci-1 (config-router) #network 192.168.0.0 // Advertising Network
Vinkovci-1 (config-router) #Exit
Vinkovci-1 (config) #Exit
Vinkovci-1 # copy running-config startup-config

Configure IGRP routing protocol on the Vinkovci-2 router

Vinkovci-2 # configure terminal
Vinkovci-2 (config) #router igrp 100 // setting IGRP routing protocol with AS 100
Vinkovci-2 (config-router) #network 192.168.5.0 // Advertising Network
Vinkovci-2 (config-router) #network 192.168.0.0 // Advertising Network
Vinkovci-2 (config-router) #Exit
Vinkovci-2 (config) #Exit
Vinkovci 2 # copy running-config startup-config


It is important to emphasize that the IGRP only works within the same Autonomous System.

To verify functionality of the IGRP protocol we can use some of the commands:

  - Show interfaceinterface
  - Show running-config
  - Show running-config interfaceinterface
  - Show running-config | begin interfaceinterface
  - Show running-config | begin igrp
  - Show ip protocols

Let's see what they look like routes that sounded the IGRP on routers that we configure.

The router Vinkovci-1
Vinkovci-1#show 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
        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

 Gateway of last resort is not set

 C    192.168.4.0 is directly connected, FastEthernet0
 C    192.168.0.0 is directly connected, Serial1
 I    192.168.5.0 [100/651] via 192.168.0.2, 00:05:21, Serial1 //Route learned by IGRP Routing Protocol
The router Vinkovci-2
Vinkovci-2#show 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
        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

 Gateway of last resort is not set

 C    192.168.0.0 is directly connected, Serial0
 C    192.168.5.0 is directly connected, FastEthernet0
 I    192.168.4.0 [100/651] via 192.168.0.1, 00:09:25, Serial0
You notice that in the top output in a route that is learned via IGRP routing protocols, IP addresses after we see the AD and metrics [100/651], which defines the default number 100 AD and 651 metric- value.

Let's check protocol: With the command 'ip protocols #show' we can see a lot of things: (Routing protocol, time update, the hold-down timer, IGRP metric, maximum hop count, the advertised network, administrative distance...)
Vinkovci-1#show ip protocols
 Routing Protocol is "igrp 100"
   Sending updates every 90 seconds, next due in 31 seconds
   Invalid after 270 seconds, hold down 280, flushed after 630
   Outgoing update filter list for all interfaces is not set
   Incoming update filter list for all interfaces is not set
   Default networks flagged in outgoing updates
   Default networks accepted from incoming updates
   IGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
   IGRP maximum hopcount 100
   IGRP maximum metric variance 1
   Redistributing: igrp 100
   Routing for Networks:
     192.168.0.0
     192.168.4.0
   Routing Information Sources:
     192.168.0.2           100      00:00:00
   Distance: (default is 100)
Here's another of output where we can see, the situation Interface, IP address, bandwidth value (1544 Kbit), Delay =1000, Reliability 255/255, Load 1/255 and the type of encapsulation.
Vinkovci-1#show interface serial 1
 Serial1 is up, line protocol is up
   Hardware is HD64570
   Internet address is 192.168.0.1/24
   MTU 1500 bytes, BW 1544 Kbit, DLY 1000 usec, rely 255/255, load 1/255
   Encapsulation HDLC, loopback not set, keepalive set (10 sec)
   Last input 00:00:00, output 00:00:00, output hang never
   Last clearing of show interface counters never
   Queueing strategy: fifo
   Output queue 0/40, 0 drops; input queue 0/75, 0 drops
   5 minute input rate 1000 bits/sec, 2 packets/sec
   5 minute output rate 1000 bits/sec, 2 packets/sec
      0 packets input, 0 bytes, 0 no buffer
      Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
      0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
      0 input packets with dribble condition detected
      0 packets output, 0 bytes, 0 underruns
      0 output errors, 0 collisions, 0 interface resets
      0 babbles, 0 late collision, 0 deferred
      0 lost carrier, 0 no carrier
      0 output buffer failures, 0 output buffers swapped out
And finally, let's see the whole configuration of one of the router
Vinkovci-1#show running-config
 Building configuration...
 !
 Version 12.1
 service timestamps debug uptime
 service timestamps log uptime
 no service password-encryption
 !
 hostname Vinkovci-1
 enable secret 5 $sdf$6978yhg$jnb76sd
 enable password cisco
 !
 ip subnet-zero
 ip host Vinkovci-2 192.168.0.2
 !
 interface Serial0
  no ip address
  no ip directed-broadcast
  shutdown
 !
 interface Serial1
  ip address 192.168.0.1 255.255.255.0
  no ip directed-broadcast
  clock rate 64000
 !
 interface FastEthernet0
  ip address 192.168.4.1 255.255.255.0
  no ip directed-broadcast
  bandwidth 100000
 !
 router igrp 100
  network 192.168.0.0
  network 192.168.4.0
 !
 ip classless
 no ip http server
 !
 line con 0
  login
  transport input none
  password cisco
 line aux 0
 line vty 0 4
  login
  password cisco
 !
 no scheduler allocate
 end
Here's how it looks when you ping from one PC on the network to another PC in another network
C:>ping 192.168.5.2
 Pinging 192.168.5.2 with 32 bytes of data:

 Reply from 192.168.5.2: bytes=32 time=60ms TTL=241
 Reply from 192.168.5.2: bytes=32 time=60ms TTL=241
 Reply from 192.168.5.2: bytes=32 time=60ms TTL=241
 Reply from 192.168.5.2: bytes=32 time=60ms TTL=241
 Reply from 192.168.5.2: bytes=32 time=60ms TTL=241

 Ping statistics for 192.168.5.2:     Packets: Sent = 5, Received = 5, Lost = 0 (0% loss),
 Approximate round trip times in milli-seconds:
      Minimum = 50ms, Maximum =  60ms, Average =  55ms

If you want more details, visit (www.cisco.com), or go to school in the Cisco Networking Academy CCNA and learn how to configure IGRP routing protocol on the Roter