# BFD和VRRP

![image-20240828162230655](https://picgo-noriu.oss-cn-beijing.aliyuncs.com/Images/image-20240828162230655.png)

### 一、PC`s  IP

### 二、VLAN

- **SW3**

  ```
  [SW3]vlan 10
  [SW3-vlan10]quit
  [SW3]port-group group-member g0/0/1 g0/0/2
  [SW3-port-group]port link-type access 
  [SW3-port-group]port default vlan 10
  [SW3-port-group]quit
  [SW3]port-group group-member g0/0/3 g0/0/4	
  [SW3-port-group]port link-type trunk 
  [SW3-port-group]port trunk allow-pass vlan all
  ```

### 三、VRRP

- **SW1**

  ```
  [SW1]vlan 10
  [SW1-vlan10]quit
  [SW1]int g0/0/1
  [SW1-GigabitEthernet0/0/1]port link-type trunk 
  [SW1-GigabitEthernet0/0/1]port trunk allow-pass vlan all
  [SW1-GigabitEthernet0/0/1]quit
  [SW1]int vlan 10
  [SW1-Vlanif10]ip add 192.168.10.254 24
  [SW1-Vlanif10]vrrp vrid 10 virtual-ip 192.168.10.254	
  [SW1-Vlanif10]vrrp vrid 10 priority 130
  ```

- **SW2**

  ```
  [SW2]vlan 10
  [SW2-vlan10]quit
  [SW2]int g0/0/1
  [SW2-GigabitEthernet0/0/1]port link-type trunk 
  [SW2-GigabitEthernet0/0/1]port trunk allow-pass vlan all
  [SW2-GigabitEthernet0/0/1]quit
  [SW2]int vlan 10
  [SW2-Vlanif10]ip add 192.168.10.252 24
  [SW2-Vlanif10]vrrp vrid 10 virtual-ip 192.168.10.254
  ```

### 四、BFD

- **SW1**

  ```
  [SW1]bfd
  [SW1-bfd]quit
  [SW1]bfd ntd2407 bind peer-ip 192.168.10.252
  [SW1-bfd-session-ntd2407]discriminator local 1
  [SW1-bfd-session-ntd2407]discriminator remote 2
  [SW1-bfd-session-ntd2407]min-tx-interval 100
  [SW1-bfd-session-ntd2407]min-rx-interval 100
  [SW1-bfd-session-ntd2407]commit
  ```

- **SW2**

  ```
  [SW2]bfd
  [SW2-bfd]quit
  [SW2]bfd ntd2407 bind peer-ip 192.168.10.251	
  [SW2-bfd-session-ntd2407]discriminator local 2
  [SW2-bfd-session-ntd2407]discriminator remote 1
  [SW2-bfd-session-ntd2407]min-tx-interval 100
  [SW2-bfd-session-ntd2407]min-rx-interval 100
  [SW2-bfd-session-ntd2407]commit
  ```

### 五、BFD与VRRP联动

- **SW2**

  ```
  [SW2]int vlan 10
  [SW2-Vlanif10]vrrp vrid 10 track bfd-session 2 increased 60
  ```

  *解释：*

  1. `[SW2]int vlan 10`
     - 进入交换机的VLAN接口配置模式，针对VLAN 10。
  2. `[SW2-Vlanif10]vrrp vrid 10 track bfd-session 2 increased 60`
     - 在VLAN接口10上配置VRRP虚拟路由器ID为10，并设置对BFD会话2的跟踪。
     - `track bfd-session 2`：指定跟踪的BFD会话，这里的会话ID是2。
     - `increased 60`：当BFD会话2的状态变为Down时，VRRP的优先级将增加60。这通常用于确保当主链路出现问题时，备份链路能够接管，提高其VRRP优先级，从而成为新的主路由器。

  > 这个配置的作用是，当BFD会话2检测到链路故障时，VRRP的优先级会增加，这有助于VRRP组中的备用路由器成为新的主路由器，从而保证网络的连续性和可靠性。
  >
  > 请注意，这个配置假设BFD会话2已经正确配置，并且与VRRP虚拟路由器关联的接口是VLAN 10。如果BFD会话状态变为Down，VRRP优先级的增加将触发VRRP主备切换。

### 六、完备性测试

- **SW1**

  ```
  [SW1]dis vrrp
    Vlanif10 | Virtual Router 10
      State : Master
      Virtual IP : 192.168.10.254
      Master IP : 192.168.10.254
      PriorityRun : 255
      PriorityConfig : 130
      MasterPriority : 255
      Preempt : YES   Delay Time : 0 s
      TimerRun : 1 s
      TimerConfig : 1 s
      Auth type : NONE
      Virtual MAC : 0000-5e00-010a
      Check TTL : YES
      Config type : normal-vrrp
      Create time : 2024-08-28 15:57:41 UTC-08:00
      Last change time : 2024-08-28 16:13:44 UTC-08:00
  ```

- **SW2**

  ```
  [SW2]dis vrrp
    Vlanif10 | Virtual Router 10
      State : Backup
      Virtual IP : 192.168.10.254
      Master IP : 192.168.10.254
      PriorityRun : 100
      PriorityConfig : 100
      MasterPriority : 255
      Preempt : YES   Delay Time : 0 s
      TimerRun : 1 s
      TimerConfig : 1 s
      Auth type : NONE
      Virtual MAC : 0000-5e00-010a
      Check TTL : YES
      Config type : normal-vrrp
      Track BFD : 2  Priority increased : 60
      BFD-session state : INITIALIZE
      Create time : 2024-08-28 15:55:20 UTC-08:00
      Last change time : 2024-08-28 16:28:55 UTC-08:00
  ```

### 七、功能性测试

![image-20240828163927888](https://picgo-noriu.oss-cn-beijing.aliyuncs.com/Images/image-20240828163927888.png)

- **SW1**

  ```
  [SW1]dis vrrp
    Vlanif10 | Virtual Router 10
      State : Initialize
      Virtual IP : 192.168.10.254
      Master IP : 0.0.0.0
      PriorityRun : 255
      PriorityConfig : 130
      MasterPriority : 0
      Preempt : YES   Delay Time : 0 s
      TimerRun : 1 s
      TimerConfig : 1 s
      Auth type : NONE
      Virtual MAC : 0000-5e00-010a
      Check TTL : YES
      Config type : normal-vrrp
      Create time : 2024-08-28 15:57:41 UTC-08:00
      Last change time : 2024-08-28 16:39:16 UTC-08:00
  ```

- **SW2**

  ```
  [SW2]dis vrrp
    Vlanif10 | Virtual Router 10
      State : Master
      Virtual IP : 192.168.10.254
      Master IP : 192.168.10.252
      PriorityRun : 100
      PriorityConfig : 100
      MasterPriority : 100
      Preempt : YES   Delay Time : 0 s
      TimerRun : 1 s
      TimerConfig : 1 s
      Auth type : NONE
      Virtual MAC : 0000-5e00-010a
      Check TTL : YES
      Config type : normal-vrrp
      Track BFD : 2  Priority increased : 60
      BFD-session state : INITIALIZE
      Create time : 2024-08-28 15:55:20 UTC-08:00
      Last change time : 2024-08-28 16:39:17 UTC-08:00
  ```