静态路由联动BFD多跳检测典型配置案例

要求正常情况下RT1和RT2互访时通过link1转发，当该路径中任意线路异常后改由link2转发，通过bfd多跳检测实现 

RT1主要配置：

#

interface LoopBack0

 ip address 1.1.1.1 255.255.255.255

#

interface GigabitEthernet0/0

 ip address 10.1.123.1 255.255.255.0

#

bfd static test peer-ip 4.4.4.4 source-ip 1.1.1.1 discriminator local 1998 remote 1998

#

 ip route-static 4.4.4.4 32 10.1.123.2

 ip route-static 10.1.234.4 32 10.1.123.2 bfd static test

 ip route-static 10.1.234.4 32 10.1.123.3 preference 65

#

RT2主要配置：

#

interface LoopBack0

 ip address 4.4.4.4 255.255.255.255

#

interface GigabitEthernet0/0

 ip address 10.1.234.4 255.255.255.0

#

bfd static test peer-ip 1.1.1.1 source-ip 4.4.4.4 discriminator local 1998 remote 1998

#

 ip route-static 1.1.1.1 32 10.1.234.2

 ip route-static 10.1.123.1 32 10.1.234.2 bfd static test

 ip route-static 10.1.123.1 32 10.1.234.3 preference 65

#

验证

RT1侧：

<RT1>dis bfd session verbose

 Total sessions: 1        Up sessions: 1        Init mode: Active

 IPv4 static session working in control packet mode:

         Session name: test

          Local discr: 1998                       Remote discr: 1998

            Source IP: 1.1.1.1                  Destination IP: 4.4.4.4

        Session state: Up

            Interface: N/A

      Min Tx interval: 1000ms               Actual Tx interval: 1000ms

      Min Rx interval: 1000ms                   Detection time: 5000ms

             Rx count: 1949                           Tx count: 1962

      Connection type: Indirect                    Up duration: 00:21:57

            Hold time: 4243ms                        Auth mode: None

       Detection mode: Async                              Slot: 0

             Protocol: STATIC4/STATIC_IPv4

              Version: 1

            Diag info: No Diagnostic

静态路由：

<RT1>dis ip routing-table protocol static

Summary count : 2

Static Routing table status : <Active>

Summary count : 2

Destination/Mask   Proto   Pre Cost        NextHop         Interface

4.4.4.4/32         Static  60  0           10.1.123.2      GE0/0

10.1.234.4/32      Static  60  0           10.1.123.2      GE0/0

RT2侧：

<RT2>dis bfd session verbose

 Total sessions: 1        Up sessions: 1        Init mode: Active

 IPv4 static session working in control packet mode:

         Session name: test

          Local discr: 1998                       Remote discr: 1998

            Source IP: 4.4.4.4                  Destination IP: 1.1.1.1

        Session state: Up

            Interface: N/A

      Min Tx interval: 1000ms               Actual Tx interval: 1000ms

      Min Rx interval: 1000ms                   Detection time: 5000ms

             Rx count: 1945                           Tx count: 2113

      Connection type: Indirect                    Up duration: 00:24:31

            Hold time: 4993ms                        Auth mode: None

       Detection mode: Async                              Slot: 0

             Protocol: STATIC4/STATIC_IPv4

              Version: 1

            Diag info: No Diagnostic

静态路由：

<RT2>dis ip routing-table protocol static

Summary count : 2

Static Routing table status : <Active>

Summary count : 2

Destination/Mask   Proto   Pre Cost        NextHop         Interface

1.1.1.1/32         Static  60  0           10.1.234.2      GE0/0

10.1.123.1/32      Static  60  0           10.1.234.2      GE0/0

模拟故障，断开link1与RT1之间的连通链路：

[link1]int g0/0

[link1-GigabitEthernet0/0]shutdown

RT1侧：

<RT1>%Jul 27 21:34:32:773 2023 RT1 BFD/5/BFD_CHANGE_FSM: Sess[1.1.1.1/4.4.4.4, LD/RD:1998/1998, Interface:N/A, SessType:Ctrl, LinkType:INET], Ver:1, Sta: UP->DOWN, Diag: 1 (Control Detection Time Expired)

<RT1>dis bfd session verbose

 Total sessions: 1        Up sessions: 0        Init mode: Active

 IPv4 static session working in control packet mode:

         Session name: test

          Local discr: 1998                       Remote discr: 1998

            Source IP: 1.1.1.1                  Destination IP: 4.4.4.4

        Session state: Down

            Interface: N/A

      Min Tx interval: 1000ms               Actual Tx interval: 1000ms

      Min Rx interval: 1000ms                   Detection time: 5000ms

             Rx count: 2232                           Tx count: 2254

      Connection type: Indirect                    Up duration: 00:00:00

            Hold time: 0ms                           Auth mode: None

       Detection mode: Async                              Slot: 0

             Protocol: STATIC4/STATIC_IPv4

              Version: 1

            Diag info: Control Detection Time Expired

<RT1>dis ip routing-table protocol static

Summary count : 2

Static Routing table status : <Active>

Summary count : 2

Destination/Mask   Proto   Pre Cost        NextHop         Interface

4.4.4.4/32         Static  60  0           10.1.123.2      GE0/0

10.1.234.4/32      Static  65  0           10.1.123.3      GE0/0

Static Routing table status : <Inactive>

Summary count : 0

RT2侧：

<RT2>%Jul 27 21:36:36:615 2023 RT2 BFD/5/BFD_CHANGE_FSM: Sess[4.4.4.4/1.1.1.1, LD/RD:1998/1998, Interface:N/A, SessType:Ctrl, LinkType:INET], Ver:1, Sta: UP->DOWN, Diag: 1 (Control Detection Time Expired)

<RT2>dis ip routing-table protocol static

Summary count : 2

Static Routing table status : <Active>

Summary count : 2

Destination/Mask   Proto   Pre Cost        NextHop         Interface

1.1.1.1/32         Static  60  0           10.1.234.2      GE0/0

10.1.123.1/32      Static  65  0           10.1.234.3      GE0/0

Static Routing table status : <Inactive>

Summary count : 0

<RT2>dis bfd session ver

 Total sessions: 1        Up sessions: 0        Init mode: Active

 IPv4 static session working in control packet mode:

         Session name: test

          Local discr: 1998                       Remote discr: 1998

            Source IP: 4.4.4.4                  Destination IP: 1.1.1.1

        Session state: Down

            Interface: N/A

      Min Tx interval: 1000ms               Actual Tx interval: 1000ms

      Min Rx interval: 1000ms                   Detection time: 5000ms

             Rx count: 2118                           Tx count: 2367

      Connection type: Indirect                    Up duration: 00:00:00

            Hold time: 0ms                           Auth mode: None

       Detection mode: Async                              Slot: 0

             Protocol: STATIC4/STATIC_IPv4

              Version: 1

            Diag info: Control Detection Time Expired