CCNP-19 IS-IS试验2
实验拓扑：
试验要求：R1 R2 R3全部采用集成的ISIS路由协议，R1 R2在区域49.0001内，R3在区域49.0002内，R1与R2之间的链路类型为L1，R2与R3之间的链路类型为L2。
试验目的：掌握基本的集成ISIS配置 实验配置：
R1：
R1(config)#router isis
R1(config-router)#net 49.0001.1111.1111.1111.00
R1(config-router)#is-type level-1
R1(config-router)#exit
R1(config)#int loop0
R1(config-if)#ip add 1.1.1.1 255.255.255.0
R1(config-if)#ip router isis
R1(config-if)#exit
R1(config)#int loop1
R1(config-if)#ip add 2.2.2.2 255.255.255.0
R1(config-if)#ip router isis
R1(config-if)#exit
R1(config)#int f0/0
R1(config-if)#ip add 199.99.1.1 255.255.255.0
R1(config-if)#ip router isis
R1(config-if)#no shu
R1(config-if)#exit
R2：
R2(config)#router isis
R2(config-router)#net 49.0001.2222.2222.2222.00
R2(config-router)#exit
R2(config)#int loop0
R2(config-if)#ip add 3.3.3.3 255.255.255.0
R2(config-if)#ip router isis
R2(config-if)#exit
R2(config)#int loop1
R2(config-if)#ip add 4.4.4.4 255.255.255.0
R2(config-if)#ip router isis
R2(config-if)#exit
R2(config)#int f0/0
R2(config-if)#ip add 199.99.1.2 255.255.255.0
R2(config-if)#ip router isis
R2(config-if)#isis circuit-type level-1
R2(config-if)#no shu
R2(config-if)#exit
R2(config)#int s1/0
R2(config-if)#ip add 199.99.2.1 255.255.255.0
R2(config-if)#ip router isis
R2(config-if)#isis circuit-type level-2-only
R2(config-if)#clock rate 64000
R2(config-if)#no shu
R2(config-if)#exit
R3：
R3(config)#router isis
R3(config-router)#net 49.0002.3333.3333.3333.00
R3(config-router)#is-type level-2-only
R3(config-router)#exit
R3(config)#int loop0
R3(config-if)#ip add 5.5.5.5 255.255.255.0
R3(config-if)#ip router isis
R3(config-if)#exit
R3(config)#int loop1
R3(config-if)#ip add 6.6.6.6 255.255.255.0
R3(config-if)#ip router isis
R3(config-if)#exit
R3(config)#int s1/0
R3(config-if)#ip add 199.99.2.2 255.255.255.0
R3(config-if)#ip router isis
R3(config-if)#no shu
R3(config-if)#exit
以上为基本的集成ISIS的配置，起Loop接口做测试，注意有一点需要提出的是，在上次试验中我既在ISIS配置模式下配置了路由器的level，又在接口模式下配置了circuit-type的level，今天又一次看ISIS的时候发现其实这两条命令之需要一条就可以了。OK，下面查看一下邻居关系：
Router#show clns is-neighbors
System Id Interface State Type Priority Circuit Id Format
R2 Fa0/0 Up L1 64 R2.03 Phase V
R2#show clns is-neighbors
System Id Interface State Type Priority Circuit Id Format
R1 Fa0/0 Up L1 64 R2.03 Phase V
R3 Se1/0 Up L2 0 00 Phase V
R3#show clns is-neighbors
System Id Interface State Type Priority Circuit Id Format
R2 Se1/0 Up L2 0 00 Phase V
邻居关系状态都UP了，表示成功建立了ISIS的邻居关系，R2.03表示在LAN环境下R2为DIS。然后我们查看一下show ip protocols：
R1#show ip protocols
Routing Protocol is "isis"
Invalid after 0 seconds, hold down 0, flushed after 0
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Redistributing: isis
Address Summarization:
None
Maximum path: 4
Routing for Networks:
Loopback0
Loopback1
FastEthernet0/0
Routing Information Sources:
Gateway Distance Last Update
3.3.3.3 115 00:00:39
Distance: (default is 115)
R2#show ip protocols
Routing Protocol is "isis"
Invalid after 0 seconds, hold down 0, flushed after 0
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Redistributing: isis
Address Summarization:
None
Maximum path: 4
Routing for Networks:
Loopback0
Loopback1
FastEthernet0/0
Serial1/0
Routing Information Sources:
Gateway Distance Last Update
5.5.5.5 115 00:00:11
1.1.1.1 115 00:00:06
Distance: (default is 115)
R3#show ip protocols
Routing Protocol is "isis"
Invalid after 0 seconds, hold down 0, flushed after 0
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Redistributing: isis
Address Summarization:
None
Maximum path: 4
Routing for Networks:
Loopback0
Loopback1
Serial1/0
Routing Information Sources:
Gateway Distance Last Update
3.3.3.3 115 00:00:11
Distance: (default is 115)
从上面的信息可以看到集成ISIS的一些信息，注意Gateway显示的是loopback0的地址，ISIS的管理距离为115，为什么会选用这个地址？会不会像OSPF选取router-id一样呢？我们做一下测试：
R3(config)#int loop2
R3(config-if)#ip add 1.1.2.1 255.255.255.0
R3(config-if)#ip router isis
R3(config-if)#end
在R3上再起一个loopback接口，IP地址要小于loopback0的IP地址，然后在R2上clear isis *后，在show ip procols查看：
R2#show ip protocols
Routing Protocol is "isis"
Invalid after 0 seconds, hold down 0, flushed after 0
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Redistributing: isis
Address Summarization:
None
Maximum path: 4
Routing for Networks:
Loopback0
Loopback1
FastEthernet0/0
Serial1/0
Routing Information Sources:
Gateway Distance Last Update
5.5.5.5 115 00:00:00
1.1.1.1 115 00:00:22
Distance: (default is 115)
没有任何变化，好的，下面我们把R3的loopback0接口地址做一下修改：
R3(config)#int loop0
R3(config-if)#ip add 1.1.3.1 255.255.255.0
R3(config-if)#end
这回再到R2上show ip procols时会发现变化：
R2#show ip protocols
Routing Protocol is "isis"
Invalid after 0 seconds, hold down 0, flushed after 0
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Redistributing: isis
Address Summarization:
None
Maximum path: 4
Routing for Networks:
Loopback0
Loopback1
FastEthernet0/0
Serial1/0
Routing Information Sources:
Gateway Distance Last Update
5.5.5.5 115 00:00:28
1.1.1.1 115 00:00:02
1.1.3.1 115 00:00:02
Distance: (default is 115)
多了一个1.1.3.1的地址，表示采用了新的R3 Loopback0接口地址，5.5.5.5的地址还在，并没有消除，等邻居计时器超时后就会消除的。由此我们可以判断出这里显示的地址为相邻路由器loopback0口的IP地址。
下面我们来查看一下LSDB：
R1#show isis database
IS-IS Level-1 Link State Database:
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
R1.00-00 * 0x00000004 0x0170 1086 0/0/0
R2.00-00 0x00000007 0x9E4A 1114 1/0/0
R2.03-00 0x00000001 0x183C 1040 0/0/0
R2#show isis database
IS-IS Level-1 Link State Database:
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
R1.00-00 0x00000004 0x0170 1162 0/0/0
R2.00-00 * 0x00000007 0x9E4A 1195 1/0/0
R2.03-00 * 0x00000001 0x183C 1120 0/0/0
IS-IS Level-2 Link State Database:
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
R2.00-00 * 0x0000000A 0x43B5 1189 0/0/0
R3.00-00 0x00000002 0x2F4C 1187 0/0/0
R3#show isis database
IS-IS Level-2 Link State Database:
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
R2.00-00 0x0000000A 0x43B5 1189 0/0/0
R3.00-00 * 0x00000002 0x2F4C 1191 0/0/0
这里可以看到在LAN环境下，R2后面的ATT为1,表示它为一个边界路由器，R2.03-00表示R2为DIS。最后我们来查看一下路由表：
R1#show ip route
Codes: 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
Gateway of last resort is 199.99.1.2 to network 0.0.0.0
1.0.0.0/24 is subnetted, 1 subnets
C 1.1.1.0 is directly connected, Loopback0
2.0.0.0/24 is subnetted, 1 subnets
C 2.2.2.0 is directly connected, Loopback1
3.0.0.0/24 is subnetted, 1 subnets
i L1 3.3.3.0 [115/20] via 199.99.1.2, FastEthernet0/0
4.0.0.0/24 is subnetted, 1 subnets
i L1 4.4.4.0 [115/20] via 199.99.1.2, FastEthernet0/0
C 199.99.1.0/24 is directly connected, FastEthernet0/0
i*L1 0.0.0.0/0 [115/10] via 199.99.1.2, FastEthernet0/0
R2#show ip route
Codes: 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
Gateway of last resort is not set
1.0.0.0/24 is subnetted, 3 subnets
i L1 1.1.1.0 [115/20] via 199.99.1.1, FastEthernet0/0
i L2 1.1.2.0 [115/20] via 199.99.2.2, Serial1/0
i L2 1.1.3.0 [115/20] via 199.99.2.2, Serial1/0
2.0.0.0/24 is subnetted, 1 subnets
i L1 2.2.2.0 [115/20] via 199.99.1.1, FastEthernet0/0
3.0.0.0/24 is subnetted, 1 subnets
C 3.3.3.0 is directly connected, Loopback0
4.0.0.0/24 is subnetted, 1 subnets
C 4.4.4.0 is directly connected, Loopback1
6.0.0.0/24 is subnetted, 1 subnets
i L2 6.6.6.0 [115/20] via 199.99.2.2, Serial1/0
C 199.99.2.0/24 is directly connected, Serial1/0
C 199.99.1.0/24 is directly connected, FastEthernet0/0
R3#show ip route
Codes: 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
Gateway of last resort is not set
1.0.0.0/24 is subnetted, 3 subnets
i L2 1.1.1.0 [115/30] via 199.99.2.1, Serial1/0
C 1.1.2.0 is directly connected, Loopback2
C 1.1.3.0 is directly connected, Loopback0
2.0.0.0/24 is subnetted, 1 subnets
i L2 2.2.2.0 [115/30] via 199.99.2.1, Serial1/0
3.0.0.0/24 is subnetted, 1 subnets
i L2 3.3.3.0 [115/20] via 199.99.2.1, Serial1/0
4.0.0.0/24 is subnetted, 1 subnets
i L2 4.4.4.0 [115/20] via 199.99.2.1, Serial1/0
6.0.0.0/24 is subnetted, 1 subnets
C 6.6.6.0 is directly connected, Loopback1
C 199.99.2.0/24 is directly connected, Serial1/0
i L2 199.99.1.0/24 [115/20] via 199.99.2.1, Serial1/0
上面用红颜色标记的部分表示都是通过ISIS学习到的，I L1表示的是LEVEL-1路由，I L2表示的是LEVEL-2的路由，I*L1表示的是缺省路由，下面在R1上ping测试一下：
R1#ping 199.99.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 199.99.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 168/191/216 ms
通了。 实验总结：掌握基本的集成ISIS配置方法，并会使用show命令对集成ISIS的配置进行检验。
本文转自loveme2351CTO博客，原文链接：http://blog.51cto.com/loveme23/47989 ，如需转载请自行联系原作者
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