实验 2-1 IS-IS 配置实验

实验目标

1. 掌握IS-IS协议基本配置
2. 掌握IS-IS协议DIS优先级修改方式
3. 掌握IS-IS协议网络类型修改方式
4. 掌握IS-IS协议外部路由引入
5. 掌握IS-IS接口cost修改方式
6. 掌握IS-IS路由渗透配置方式

拓扑图

场景

使用IS-IS协议作为某网络的IGP，R1和R5运行在49.0002区域Level-2，R2、R3和R4运行在49.0001区域，R4是Level-1路由器，R2和R3作为Level-1-2路由器。要求：R4可以访问R5引入的外部路由；R4连接S5的接口作为DIS；R1和R5之间使用点到点链路；从R4访问R5的上下行流量应该从以太网接口进行转发，可以通过cost和路由渗透进行选路控制；交换机不做额外的配置，仅透明转发。

配置

配置基础的IP信息

[R1]interface loopback 0
[R1-LoopBack0]ip address 10.0.1.1 32
[R1-LoopBack0]quit
[R1]interface GigabitEthernet 0/0/0 
[R1-GigabitEthernet0/0/0]ip address 10.0.15.1 24
[R1-GigabitEthernet0/0/0]quit
[R1]interface GigabitEthernet 0/0/1
[R1-GigabitEthernet0/0/1]ip address 10.0.13.1 24
[R1-GigabitEthernet0/0/1]quit
[R1]interface interface Serial1/0/0
[R1-Serial1/0/0]ip address 10.0.12.1 24
[R1-Serial1/0/0]quit

[R2]interface  LoopBack 0 
[R2-LoopBack0]ip address 10.0.2.2 32
[R2-LoopBack0]quit
[R2]interface GigabitEthernet 0/0/0
[R2-GigabitEthernet0/0/0]ip address 10.0.234.2 24
[R2-GigabitEthernet0/0/0]quit
[R2]interface Serial1/0/0
[R2-Serial1/0/0]ip address 10.0.12.2 24
[R2-Serial1/0/0]quit

[R3]interface  LoopBack 0 
[R3-LoopBack0]ip address 10.0.3.3 32
[R3-LoopBack0]quit
[R3]interface GigabitEthernet 0/0/0
[R3-GigabitEthernet0/0/0]ip address 10.0.234.3 24
[R3-GigabitEthernet0/0/0]quit
[R3]interface GigabitEthernet 0/0/1
[R3-GigabitEthernet0/0/1]ip address 10.0.13.3 24
[R3-GigabitEthernet0/0/1]quit

[R4]interface  LoopBack 0 
[R4-LoopBack0]ip address 10.0.4.4 32
[R4-LoopBack0]quit
[R4]interface GigabitEthernet 0/0/0
[R4-GigabitEthernet0/0/0]ip address 10.0.234.4 24
[R4-GigabitEthernet0/0/0]quit
 
[R5]interface  LoopBack 0 
[R5-LoopBack0]ip address 10.0.5.5 32
[R5-LoopBack0]quit
[R5]interface GigabitEthernet 0/0/0
[R5-GigabitEthernet0/0/0]ip address 10.0.15.5 24
[R5-GigabitEthernet0/0/0]quit

接下来进行ISIS的基本配置

[R1]isis
[R1-isis-1]network-entity 49.0002.0000.0000.0001.00
[R1-isis-1]is-level level-2
[R1-isis-1]quit
[R1]interface LoopBack 0
[R1-LoopBack0]isis enable
[R1-LoopBack0]quit
[R1]interface GigabitEthernet 0/0/0
[R1-GigabitEthernet0/0/0]isis enable
[R1-GigabitEthernet0/0/0]quit
[R1]interface GigabitEthernet 0/0/1
[R1-GigabitEthernet0/0/1]isis enable
[R1-GigabitEthernet0/0/1]quit
[R1]interface Serial 1/0/0
[R1-Serial1/0/0]isis enable
[R1-Serial1/0/0]quit

[R2]isis 1
[R2-isis-1]network-entity 49.0001.0000.0000.0002.00
[R2-isis-1]quit
[R2]interface LoopBack 0
[R2-LoopBack0]isis enable
[R2-LoopBack0]quit
[R2]interface GigabitEthernet 0/0/0
[R2-GigabitEthernet0/0/0]isis enable
[R2-GigabitEthernet0/0/0]quit
[R2]interface Serial 1/0/0
[R2-Serial1/0/0]isis enable
[R2-Serial1/0/0]quit

[R3]isis 1
[R3-isis-1]network-entity 49.0001.0000.0000.0003.00
[R3-isis-1]quit
[R3]interface LoopBack 0
[R3-LoopBack0]isis enable
[R3-LoopBack0]quit
[R3]interface GigabitEthernet 0/0/0
[R3-GigabitEthernet0/0/0]isis enable
[R3-GigabitEthernet0/0/0]quit
[R3]interface GigabitEthernet 0/0/1
[R3-GigabitEthernet0/0/1]isis enable
[R3-GigabitEthernet0/0/1]quit

[R4]isis 1
[R4-isis-1]network-entity 49.0001.0000.0000.0004.00
[R4-isis-1]is-level level-1
[R4-isis-1]quit
[R4]interface LoopBack 0
[R4-LoopBack0]isis enable
[R4-LoopBack0]quit
[R4]interface GigabitEthernet 0/0/0
[R4-GigabitEthernet0/0/0]isis enable
[R4-GigabitEthernet0/0/0]quit

[R5]isis 1
[R5-isis-1]network-entity 49.0002.0000.0000.0005.00
[R5-isis-1]is-level level-2
[R5-isis-1]quit
[R5]interface LoopBack 0
[R5-LoopBack0]isis enable
[R5-LoopBack0]quit
[R5]interface GigabitEthernet 0/0/0
[R5-GigabitEthernet0/0/0]isis enable
[R5-GigabitEthernet0/0/0]quit

R2、R3和R4在一个广播网络下建立邻居，因此需要选举DIS，默认情况下，DIS优先级都为64，如果优先级相同MAC地址大的接口将成为DIS，我们希望选举更为清晰，因此通过修改R4的DIS优先级来保证其成为DIS。

[R4]interface  GigabitEthernet 0/0/0
[R4-GigabitEthernet0/0/0]isis dis-priority 120
[R4-GigabitEthernet0/0/0]quit

在广播网络中，IS-IS默认会将接口的circuit-type设置为广播模式，并参与DIS的选举。但在拓扑中R1和R5之间的以太网只有两台路由器，我们可以将这两台路由器之间的互联接口设置为点到点模式，进行优化。

[R1]interface  GigabitEthernet 0/0/0
[R1-GigabitEthernet0/0/0]isis circuit-type p2p 
[R1-GigabitEthernet0/0/0]quit

[R5]interface  GigabitEthernet 0/0/0
[R5-GigabitEthernet0/0/0]isis circuit-type p2p
[R5-GigabitEthernet0/0/0]quit

在R5上创建新的LoopBack口，并引入到isis进程

[R5]interface LoopBack 1
[R5-LoopBack1]ip address 192.168.1.1 24
[R5-LoopBack1]quit
[R5]interface LoopBack 2
[R5-LoopBack2]ip address 192.168.2.1 24
[R5-LoopBack2]quit
[R5]interface LoopBack 3
[R5-LoopBack3]ip address 192.168.3.1 24
[R5-LoopBack3]quit
[R5]isis
[R5-isis-1]import-route direct level-2 
[R5-isis-1]quit

默认情况下，IS-IS接口cost值为10，不会基于带宽自动计算，需要修改IS-IS接口Cost值

[R1]interface Serial 1/0/0
[R1-Serial1/0/0]isis cost 15
[R1-Serial1/0/0]quit

观察R4的数据转发，由于R4对Level-2网络状况一无所知，因此使用负载均衡转发数据到R2和R3，如果我们希望R4不使用R2到R1之间的链路，可以通过路由渗透将Level-2的路由引入到Level-1中，通过路由最长匹配选路，从R3转发去往R5的数据包。

[R3]isis
[R3-isis-1]import-route isis level-2 into level-1
[R3-isis-1]quit