EIGRP邻居关系建立的条件分析

123rew

1：配置地址(略)，并配置EIGRP
R1(config)#routereigrp 100
R1(config-router)#noauto-summary
R1(config-router)#net192.168.12.0
R1(config-router)#net10.0.0.0

R2(config)#routereigrp 100
R2(config-router)#noauto-summary
R2(config-router)#net192.168.12.0
R2(config-router)#net192.168.23.0
R2(config-router)#net172.16.0.0

R3(config)#routereigrp 200
R3(config-router)#noauto-summary
R3(config-router)#net192.168.23.0
R3(config-router)#net192.168.0.0
R3(config-router)#net192.168.1.0

2：邻居关系的建立条件—相同的AS号
R2#show ip eigrp neighbors
IP-EIGRPneighbors for process 100
H   Address                 Interface       Hold Uptime   SRTT  RTO  Q  Seq
                                           (sec)         (ms)       Cnt Num
0   192.168.12.1            Fa0/0             13 00:01:18  154  924  0  3

以上显示说明：配置不同AS号的EIGRP路由器不能建立邻居关系。

R3(config)#norouter eigrp 200
R3(config)#routereigrp 100
R3(config-router)#noauto-summary
R3(config-router)#net192.168.23.0
R3(config-router)#net192.168.1.0   
R3(config-router)#net192.168.0.0

R2#show ip eigrp neighbors
IP-EIGRPneighbors for process 100
H   Address                 Interface       Hold Uptime   SRTT  RTO  Q  Seq
                                           (sec)         (ms)       Cnt Num
1   192.168.23.2            Se1/1             13 00:00:56  167 1002  0  6
0   192.168.12.1            Fa0/0             11 00:05:08  146  876  0  3

3：邻居关系的建立条件—相同的K值
R3(config)#routerei 100
R3(config-router)#metricweights 0 1 1 1 1 1

R2#show ip protocols
RoutingProtocol is "eigrp 100"
  Outgoing update filter list for allinterfaces is not set
  Incoming update filter list for allinterfaces is not set
  Default networks flagged in outgoing updates
  Default networks accepted from incomingupdates
  EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0
（以下省略部分输出）

R3(config-router)#
*Jan19 13:02:26.071: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.23.1(Serial1/0) is down: metric changed
R3(config-router)#
*Jan19 13:02:30.447: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.23.1(Serial1/0) is down: K-value mismatch

R2#
*Jan19 13:02:43.263: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.23.2(Serial1/1) is down: K-value mismatch
R2#
*Jan19 13:02:48.015: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.23.2(Serial1/1) is down: K-value mismatch

以上显示说明：EIGRP路由器配置不同的K值，不能建立邻居关系

R3(config)#routerei 100
R3(config-router)#metricweights 0 1 0 1 0 0

R3(config-router)#
*Jan19 13:04:09.495: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.23.1(Serial1/0) is up: new adjacency

R2#
*Jan19 13:04:09.091: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.23.2(Serial1/1) is up: new adjacency
4：邻居关系建立的条件—邻居接口的地址掩码相互包含
R2(config)#interfa0/0
R2(config-if)#shutdown
R2(config-if)#ipadd 192.168.12.2 255.255.255.252
R2(config-if)#noshutdown

R2(config-if)#
*Jan19 13:07:13.099: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.1(FastEthernet0/0) is up: new adjacency

R3(config)#inters1/0
R3(config-if)#shutdown
R3(config-if)#ipadd 192.168.23.2 255.255.255.252
R3(config-if)#noshutdown

R3(config-if)#
*Jan19 13:08:32.215: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.23.1(Serial1/0) is up: new adjacency

R1(config-router)#interfa0/0
R1(config-if)#shutdown
R1(config-if)#ipadd 192.168.12.4255.255.255.0
R1(config-if)#noshutdown

R1(config-if)#
*Jan19 13:10:20.563: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.2(FastEthernet0/0) is up: new adjacency
R1(config-if)#
*Jan19 13:11:40.191: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.2(FastEthernet0/0) is down: retry limit exceeded
R1(config-if)#
*Jan19 13:11:43.151: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.2 (FastEthernet0/0)is up: newadjacency

R2(config-if)#
*Jan19 13:10:16.131: IP-EIGRP(Default-IP-Routing-Table:100): Neighbor 192.168.12.4 not on commonsubnet for FastEthernet0/0
R2(config-if)#
*Jan19 13:10:29.763: IP-EIGRP(Default-IP-Routing-Table:100): Neighbor 192.168.12.4 not on commonsubnet for FastEthernet0/0

以上显示说明：在EIGRP建立邻居关系，无论是点到点网络还是广播网络，只要和邻居接口的地址掩码相互包含即可，这一点要注意区别OSPF的现象。

R1(config-router)#interfa0/0
R1(config-if)#ipadd 192.168.12.1 255.255.255.0
R1(config-if)#
*Jan19 13:13:47.659: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.2(FastEthernet0/0) is down: address changed
R1(config-if)#
*Jan19 13:13:50.131: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.2 (FastEthernet0/0)is up: newadjacency

5：邻居关系建立的条件—邻居接口的计时器不一定要相同，但要匹配
R1(config)#interfa0/0
R1(config-if)#shutdown
R1(config-if)#iphello-interval ei 100 1
R1(config-if)#iphold-time ei 100 3
R1(config-if)#noshutdown

R1(config-if)#
*Jan19 13:22:00.447: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.2(FastEthernet0/0) is up: new adjacency

以上显示说明：在适当的计时器下，邻居计时器不同，也能够建立邻居关系。

R1(config)#interfa0/0
R1(config-if)#shutdown
R1(config-if)#iphello-interval ei 100 1
R1(config-if)#iphold-time ei 100 15

R2(config)#interfa0/0
R2(config-if)#iphello-interval ei 100 5                        
R2(config-if)#iphold-time ei 100 3

R1(config)#interfa0/0
R1(config-if)#noshutdown

R1(config-if)#
*Jan19 13:27:29.247: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.2(FastEthernet0/0) is up: new adjacency
R1(config-if)#
*Jan19 13:27:33.231: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.2(FastEthernet0/0) is down: holding time expired
*Jan19 13:27:33.883: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.2(FastEthernet0/0) is up: new adjacency
R1(config-if)#
*Jan19 13:27:37.235: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.2(FastEthernet0/0) is down: holding time expired
R1(config-if)#
*Jan19 13:27:38.323: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.2(FastEthernet0/0) is up: new adjacency
R2(config-if)#
*Jan19 13:27:28.723: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.1(FastEthernet0/0) is up: new adjacency
R2(config-if)#
*Jan19 13:27:32.811: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.1(FastEthernet0/0) is down: Interface Goodbye received
*Jan19 13:27:33.455: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.1 (FastEthernet0/0)is up: newadjacency
R2(config-if)#
*Jan19 13:27:36.863: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.1(FastEthernet0/0) is down: Interface Goodbye received
*Jan19 13:27:37.823: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.1(FastEthernet0/0) is up: new adjacency
R2(config-if)#
*Jan19 13:27:41.979: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 192.168.12.1(FastEthernet0/0) is down: Interface Goodbye received

以上显示说明：邻居计时器不同，邻居关系也可能有问题。