一篇掌握BFD技术（一）：静态路由与BFD联动配置

1. 实验目的

1. 熟悉静态路由与BFD联动的应用场景
2. 掌握静态路由与BFD联动的配置

2. 实验拓扑

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3. 实验步骤

1）配置IP地址

AR1的配置

system-view

Enter system view, return user view with Ctrl+Z.

[Huawei]undo info-center enable

Info: Information center is disabled.

[Huawei]sysname AR1

[AR1]interface g0/0/0

[AR1-GigabitEthernet0/0/0]ip address 12.1.1.1 24

[AR1-GigabitEthernet0/0/0]quit

[AR1]interface g0/0/1

[AR1-GigabitEthernet0/0/1]ip address 13.1.1.1 24

[AR1-GigabitEthernet0/0/1]quit

[AR1]interface LoopBack 0

[AR1-LoopBack0]ip address 1.1.1.1 32

[AR1-LoopBack0]quit

AR2的配置

system-view

Enter system view, return user view with Ctrl+Z.

[Huawei]undo info-center enable

Info: Information center is disabled.

[Huawei]sysname AR2

[AR2]interface g0/0/1

[AR2-GigabitEthernet0/0/1]ip address 12.1.1.2 24

[AR2-GigabitEthernet0/0/1]quit

[AR2]interface g0/0/0

[AR2-GigabitEthernet0/0/0]ip address 24.1.1.2 24

[AR2-GigabitEthernet0/0/0]quit

AR3的配置

system-view

Enter system view, return user view with Ctrl+Z.

[Huawei]undo info-center enable

Info: Information center is disabled.

[Huawei]sysname AR3

[AR3]interface g0/0/0

[AR3-GigabitEthernet0/0/0]ip address 13.1.1.3 24

[AR3-GigabitEthernet0/0/0]quit

[AR3]interface g0/0/1

[AR3-GigabitEthernet0/0/1]ip address 34.1.1.3 24

[AR3-GigabitEthernet0/0/1]quit

AR4的配置

system-view

Enter system view, return user view with Ctrl+Z.

[Huawei]undo info-center enable

Info: Information center is disabled.

[Huawei]sysname AR4

[AR4]interface g0/0/1

[AR4-GigabitEthernet0/0/1]ip address 24.1.1.4 24

[AR4-GigabitEthernet0/0/1]quit

[AR4]interface g0/0/0

[AR4-GigabitEthernet0/0/0]ip address 34.1.1.4 24

[AR4-GigabitEthernet0/0/0]quit

[AR4]interface LoopBack 0

[AR4-LoopBack0]ip address 4.4.4.4 32

[AR4-LoopBack0]quit

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2）在AR1与AR2之间建立BFD会话，并与静态路由绑定，实现故障快速检测和路径快速收敛。

AR1的配置

[AR1]bfd   //全局使能BFD功能，并进入BFD全局视图

[AR1]bfd 102 bind peer-ip 12.1.1.2 interface g0/0/0  //配置一个名字为102的BFD会话，使用12.1.1.2对绑定本端接口g0/0/0接口的单跳链路进行检测

[AR1-bfd-session-102]discriminator local 100  //BFD会话的本地标识符为100

[AR1-bfd-session-102]discriminator remote 200  //BFD会话的远端标识符为200

[AR1-bfd-session-102]commit  //提交配置

AR2的配置

[AR2]bfd

[AR2-bfd]quit

[AR2]bfd 201 bind peer-ip 12.1.1.1 interface g0/0/1

[AR2-bfd-session-201]discriminator local 200

[AR2-bfd-session-201]discriminator remote 100

[AR2-bfd-session-201]commit

3）配置静态路由

AR1的配置：

[AR1]ip route-static 4.4.4.4 32 12.1.1.2 track bfd-session 102

[AR1]ip route-static 4.4.4.4 32 13.1.1.3 preference 100

AR2的配置

[AR2]ip route-static 1.1.1.1 32 12.1.1.1

[AR2]ip route-static 4.4.4.4 32 24.1.1.4

AR3的配置

[AR3]ip route-static 1.1.1.1 32 13.1.1.1

[AR3]ip route-static 4.4.4.4 32 34.1.1.4

AR4的配置

[AR4]ip route-static 1.1.1.1 32 24.1.1.2

[AR4]ip route-static 1.1.1.1 32 34.1.1.3

4）实验调试

在AR1上访问4.4.4.4

[AR1]ping -a 1.1.1.1 4.4.4.4

  PING 4.4.4.4: 56  data bytes, press CTRL_C to break

    Reply from 4.4.4.4: bytes=56 Sequence=1 ttl=254 time=30 ms

    Reply from 4.4.4.4: bytes=56 Sequence=2 ttl=254 time=30 ms

    Reply from 4.4.4.4: bytes=56 Sequence=3 ttl=254 time=30 ms

    Reply from 4.4.4.4: bytes=56 Sequence=4 ttl=254 time=30 ms

    Reply from 4.4.4.4: bytes=56 Sequence=5 ttl=254 time=20 ms

  --- 4.4.4.4 ping statistics ---

    5 packet(s) transmitted

    5 packet(s) received

    0.00% packet loss

    round-trip min/avg/max = 20/28/30 ms

通过以上输出可以看到1.1.1.1可以访问4.4.4.4

在AR1上tracert 4.4.4.4

tracert -a 1.1.1.1 4.4.4.4

 traceroute to  4.4.4.4(4.4.4.4), max hops: 30 ,packet length: 40,press CTRL_C to break

 1 12.1.1.2 40 ms  50 ms  50 ms

 2 24.1.1.4 30 ms  30 ms  40 ms

在R2的g0/0/1口抓包查看BFD包文

默认情况下：BFD的缺省参数台下：

发送间隔1000毫秒

接收间隔1000毫秒

本地检测倍数3

在AR1上查看BFD信息

[AR1]display bfd session all verbose

----------------------------------------------------------------------------

Session MIndex : 512       (One Hop) State : Up        Name : 102     // bfd会话状态为up

----------------------------------------------------------------------------

  Local Discriminator    : 100              Remote Discriminator   : 200      

  Session Detect Mode    : Asynchronous Mode Without Echo Function            

  BFD Bind Type          : Interface(GigabitEthernet0/0/0)                    

  Bind Session Type      : Static       //静态bfd                                       

  Bind Peer IP Address   : 12.1.1.2                                           

  NextHop Ip Address     : 12.1.1.2                                           

  Bind Interface         : GigabitEthernet0/0/0                               

  FSM Board Id           : 0                TOS-EXP                : 7        

  Min Tx Interval (ms)   : 1000             Min Rx Interval (ms)   : 1000     

  Actual Tx Interval (ms): 1000             Actual Rx Interval (ms): 1000     

  Local Detect Multi     : 3                Detect Interval (ms)   : 3000   //故障检测间隔

  Echo Passive           : Disable          Acl Number             : -        

  Destination Port       : 3784             TTL                    : 255      

  Proc Interface Status  : Disable          Process PST            : Disable  

  WTR Interval (ms)      : -                                                   

  Active Multi           : 3                                                  

  Last Local Diagnostic  : Control Detection Time Expired                     

  Bind Application       : No Application Bind

  Session TX TmrID       : -                Session Detect TmrID   : -        

  Session Init TmrID     : -                Session WTR TmrID      : -        

  Session Echo Tx TmrID  : -                                                  

  PDT Index              : FSM-0 | RCV-0 | IF-0 | TOKEN-0                     

  Session Description    : -                                                  

----------------------------------------------------------------------------

                                         

     Total UP/DOWN Session Number : 1/0

关闭AR2的g0/0/1口，然后tracert 4.4.4.4

[AR2]interface g0/0/1

[AR2-GigabitEthernet0/0/1]shutdown

[AR2-GigabitEthernet0/0/1]quit

tracert -a 1.1.1.1 4.4.4.4

 traceroute to  4.4.4.4(4.4.4.4), max hops: 30 ,packet length: 40,press CTRL_C to break

 1 13.1.1.3 30 ms  20 ms  20 ms

 2 34.1.1.4 30 ms  40 ms  20 ms

  一旦AR1与AR2之间的链路产生了问题，3S就可以切换到另一条链路上去

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