这个是上课时 给学生演示的一个CCNA  IGRP小实验!!!
配置IGRP只需要两个必要的步骤：
SETP1：使用router Igrp process-Id 命令启动IGRP进程
SETP2:使用network命令来指定运行IGRP协议的每个主网络
在做IGRP时要主意它的AS号
IGRP进程ID范围是（1---65535）默认的IGRP进程ID是100

此实验需求是:通过IGRP协议使R1,R2.R3分别学到1.1.1.0/2.2.2.0/3.3.3.0的网络
setp1:底层配置使底层通信
setp2:跑协议IGRP AS号为100
setp3:观察现象
setp4:用ping测试
主意在IGRP中它只有一张表是路由表
R1路由器的配置如下：
interface Loopback0
 ip address 1.1.1.1 255.255.255.0
interface Serial2/1
 ip address 12.0.0.1 255.255.255.0
router igrp 100
 network 1.0.0.0
 network 12.0.0.0
R2路由器的配置如下：
interface Loopback0
 ip address 2.2.2.2 255.255.255.0
interface Serial2/1
 ip address 12.0.0.2 255.255.255.0
interface Serial2/2
 ip address 23.0.0.1 255.255.255.0
router igrp 100
 network 2.0.0.0
 network 12.0.0.0
 network 23.0.0.0
R3路由器的配置如下：
interface Loopback0
 ip address 3.3.3.3 255.255.255.0
interface Serial2/1
 ip address 23.0.0.2 255.255.255.0
router igrp 100
 network 3.0.0.0
 network 23.0.0.0
R1#sho 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, ia - IS-IS inter area
       * - candidate default, U - per-user static route, o - ODR
       P - periodic downloaded static route

Gateway of last resort is not set

     1.0.0.0/24 is subnetted, 1 subnets
C       1.1.1.0 is directly connected, Loopback0
I    2.0.0.0/8 [100/8976] via 12.0.0.2, 00:00:10, Serial2/1
I    3.0.0.0/8 [100/10976] via 12.0.0.2, 00:00:10, Serial2/1
I    23.0.0.0/8 [100/10476] via 12.0.0.2, 00:00:10, Serial2/1
     12.0.0.0/24 is subnetted, 1 subnets
C       12.0.0.0 is directly connected, Serial2/1
R2#sho 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, ia - IS-IS inter area
       * - candidate default, U - per-user static route, o - ODR
       P - periodic downloaded static route

Gateway of last resort is not set

I    1.0.0.0/8 [100/8976] via 12.0.0.1, 00:00:20, Serial2/1
     2.0.0.0/24 is subnetted, 1 subnets
C       2.2.2.0 is directly connected, Loopback0
I    3.0.0.0/8 [100/8976] via 23.0.0.2, 00:01:00, Serial2/2
     23.0.0.0/24 is subnetted, 1 subnets
C       23.0.0.0 is directly connected, Serial2/2
     12.0.0.0/24 is subnetted, 1 subnets
C       12.0.0.0 is directly connected, Serial2/1
R3#sho 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, ia - IS-IS inter area
       * - candidate default, U - per-user static route, o - ODR
       P - periodic downloaded static route

Gateway of last resort is not set

I    1.0.0.0/8 [100/10976] via 23.0.0.1, 00:00:23, Serial2/1
I    2.0.0.0/8 [100/8976] via 23.0.0.1, 00:00:23, Serial2/1
     3.0.0.0/24 is subnetted, 1 subnets
C       3.3.3.0 is directly connected, Loopback0
     23.0.0.0/24 is subnetted, 1 subnets
C       23.0.0.0 is directly connected, Serial2/1
I    12.0.0.0/8 [100/10476] via 23.0.0.1, 00:00:23, Serial2/1
R3#ping 1.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 88/160/320 ms
R1#ping 3.3.3.3

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 92/151/200 ms
R2#ping 1.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 28/75/108 ms
R2#ping 3.3.3.3

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 32/72/100 ms
R2#debug ip igrp events
IGRP event debugging is on
R2#clear ip rout *     
R2#
00:49:34: IGRP: broadcasting request on Serial2/1
00:49:34: IGRP: broadcasting request on Serial2/2
00:49:34: IGRP: broadcasting request on Loopback0
00:49:34: IGRP: edition is now 8
00:49:34: IGRP: sending update to 255.255.255.255 via Serial2/1 (12.0.0.2)
00:49:34: IGRP: Update contains 0 interior, 2 system, and 0 exterior routes.
00:49:34: IGRP: Total routes in update: 2
00:49:34: IGRP: sending update to 255.255.255.255 via Serial2/2 (23.0.0.1)
00:49:34: IGRP: Update contains 0 interior, 2 system, and 0 exterior routes.
00:49:34: IGRP: Total routes in update: 2
00:49:34: IGRP: sending update to 255.255.255.255 via Loopback0 (2.2.2.2)
00:49:34: IGRP: Update contains 0 interior, 2 system, and 0 exterior routes.
00:49:34: IGRP: Total routes in update: 2
00:49:34: IGRP: received update from 23.0.0.2 on Serial2/2
00:49:34: IGRP: Update contains 0 interior, 1 system, and 0 exterior routes.
00:49:34: IGRP: Total routes in update: 1
00:49:34: IGRP: edition is now 9
00:49
R2#:34: IGRP: sending update to 255.255.255.255 via Serial2/1 (12.0.0.2)
00:49:34: IGRP: Update contains 0 interior, 3 system, and 0 exterior routes.
00:49:34: IGRP: Total routes in update: 3
00:49:34: IGRP: sending update to 255.255.255.255 via Serial2/2 (23.0.0.1)
00:49:34: IGRP: Update contains 0 interior, 2 system, and 0 exterior routes.
00:49:34: IGRP: Total routes in update: 2
00:49:34: IGRP: sending update to 255.255.255.255 via Loopback0 (2.2.2.2)
00:49:34: IGRP: Update contains 0 interior, 3 system, and 0 exterior routes.
00:49:34: IGRP: Total routes in update: 3
00:49:34: IGRP: received update from 12.0.0.1 on Serial2/1
00:49:34: IGRP: Update contains 0 interior, 1 system, and 0 exterior routes.
00:49:34: IGRP: Total routes in update: 1
00:49:34: IGRP: edition is now 10
00:49:34: IGRP: sending update to 255.255.255.255 via Serial2/1 (12.0.0.2)
00:49:34: IGRP: Update contains 0 interior, 3 system, and 0 exterior routes.
00:49:34: IGRP: Total routes in update: 3
0
R2#u0:49:34: IGRP: sending update to 255.255.255.255 via Serial2/2 (23.0.0.1)
00:49:34: IGRP: Update contains 0 interior, 3 system, and 0 exterior routes.
00:49:34: IGRP: Total routes in update: 3
00:49:34: IGRP: sending update to 255.255.255.255 via Loopback0 (2.2.2.2)
00:49:34: IGRP: Update contains 0 interior, 4 system, and 0 exterior routes.
00:49:34: IGRP: Total routes in update: 4
R1#debug  ip igrp events
R1#
00:50:42: IGRP: broadcasting request on Serial2/1
00:50:42: IGRP: broadcasting request on Loopback0
00:50:42: IGRP: edition is now 2
00:50:42: IGRP: sending update to 255.255.255.255 via Serial2/1 (12.0.0.1)
00:50:42: IGRP: Update contains 0 interior, 1 system, and 0 exterior routes.
00:50:42: IGRP: Total routes in update: 1
00:50:42: IGRP: sending update to 255.255.255.255 via Loopback0 (1.1.1.1)
00:50:42: IGRP: Update contains 0 interior, 1 system, and 0 exterior routes.
00:50:42: IGRP: Total routes in update: 1
00:50:42: IGRP: received update from 12.0.0.2 on Serial2/1
00:50:42: IGRP: Update contains 0 interior, 3 system, and 0 exterior routes.
R1#
00:50:42: IGRP: Total routes in update: 3
00:50:42: IGRP: edition is now 3
00:50:42: IGRP: sending update to 255.255.255.255 via Serial2/1 (12.0.0.1)
00:50:42: IGRP: Update contains 0 interior, 1 system, and 0 exterior routes.
00:50:42: IGRP: Total routes in update: 1
00:50:42: IGRP: sending update to 255.255.255.255 via Loopback0 (1.1.1.1)
00:50:42: IGRP: Update contains 0 interior, 4 system, and 0 exterior routes.
00:50:42: IGRP: Total routes in update: 4
R3#debug ip igrp events
00:53:02: IGRP: broadcasting request on Serial2/1
00:53:02: IGRP: broadcasting request on Loopback0
00:53:02: IGRP: edition is now 3
00:53:02: IGRP: sending update to 255.255.255.255 via Serial2/1 (23.0.0.2)
00:53:02: IGRP: Update contains 0 interior, 1 system, and 0 exterior routes.
00:53:02: IGRP: Total routes in update: 1
00:53:02: IGRP: sending update to 255.255.255.255 via Loopback0 (3.3.3.3)
00:53:02: IGRP: Update contains 0 interior, 1 system, and 0 exterior routes.
00:53:02: IGRP: Total routes in update: 1
00:53:02: IGRP: received update from 23.0.0.1 on Serial2/1
00:53:02: IGRP: Update contains 0 interior, 3 system, and 0 exterior routes.
R3#
00:53:02: IGRP: Total routes in update: 3
00:53:02: IGRP: edition is now 4
00:53:02: IGRP: sending update to 255.255.255.255 via Serial2/1 (23.0.0.2)
00:53:02: IGRP: Update contains 0 interior, 1 system, and 0 exterior routes.
00:53:02: IGRP: Total routes in update: 1
00:53:02: IGRP: sending update to 255.255.255.255 via Loopback0 (3.3.3.3)
00:53:02: IGRP: Update contains 0 interior, 4 system, and 0 exterior routes.
00:53:02: IGRP: Total routes in update: 4
R3#u all