IS-IS与动态BFD联动示例

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组网需求

  1. 三台路由器通过IS-IS协议实现互联互通
  2. Router A与Router B之间通过一台二层交换机互联
  3. 要求Router A与Router B之间故障，两台路由器能够快速对故障做出反应，并将流量切到Router C链路转发

实验拓扑

配置思路

  1. 配置路由器基本功能以及IP地址
  2. 配置IS-IS协议以及接口使能IS-IS
  3. 配置IS-IS接口开销值控制路由选路，Router A到Router B作为主链路
  4. 配置动态BFD
  5. 接口使能IS-IS与BFD联动

配置命令

  1. 配置路由器基本功能以及IP地址

    • Router A配置

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      sys
      sys Router A
      int g0/0/0
        ip add 3.3.3.1 30
      int g0/0/1
        ip add 1.1.1.1 30

  • Router B配置

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    sys
    sys Router B
    int g0/0/0
      ip add 3.3.3.2 30
    int g0/0/2
      ip add 2.2.2.1 30

  • Router C配置

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    sys
    sys Router C
    int g0/0/1
      ip add 1.1.1.2 30
    int g0/0/2
      ip add 2.2.2.2 30

  1. 配置IS-IS协议以及接口使能IS-IS协议

    • Router A配置

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      sys
      isis 1
        is-level level-2
        network-entity 86.0010.0030.0300.3001.00
        q
      int g0/0/0
        isis enable 1
        isis small-hello
      int g0/0/1
        isis enable 1
        isis small-hello

  • Router B配置

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    sys
    isis 1
      is-level level-2
      network-entity 86.0010.0030.0300.3002.00
      q
    int g0/0/0
      isis enable 1
      isis small-hello
    int g0/0/2
      isis enable 1
      isis small-hello

  • Router C配置

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    sys
    isis 1
      is-level level-2
      network-entity 86.0010.0010.0100.1002.00
    int g0/0/1
      isis enable 1
      isis small-hello
    int g0/0/2
      isis enable 1
      isis small-hello

  1. 配置IS-IS接口开销值控制路由选路

    • Router A配置

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      sys
      int g0/0/0
        isis cost 5

  • Router B配置

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    sys
    int g0/0/0
      isis cost 5

  1. 配置动态BFD，并与IS-IS协议联动

    • Router A配置

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      sys
      bfd
      q
      isis 1
        bfd all-interface enable
        q

  • Router B配置

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    sys
    bfd
    q
    isis 1
      bfd all-interface enable
      q

  • Router C配置

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    sys
    bfd
    q
    isis 1
      bfd all-interface enable
      q

  1. 接口使能IS-IS BFD，并配置特性

    • Router A配置

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      sys
      int g0/0/0
        isis bfd enable
        isis bfd min-tx-interval 100
        isis bfd min-rx-interval 100
        isis bfd detect-multiplier 4

  • Router B配置

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    sys
    int g0/0/0
      isis bfd enable
      isis bfd min-tx-interval 100
      isis bfd min-rx-interval 100
      isis bfd detect-multiplier 4

测试结果

  1. 查看IS-IS邻居

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    dis isis peer
    <Router A>dis isis peer

                              Peer information for ISIS(1)

      System Id     Interface          Circuit Id       State HoldTime Type     PRI
    -------------------------------------------------------------------------------
    0030.0300.3002  GE0/0/0            0030.0300.3001.01 Up   28s      L2       64 
    0010.0100.1002  GE0/0/1            0010.0100.1002.01 Up   8s       L2       64 

    Total Peer(s): 2

  1. 查看路由表

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    <Router A>dis ip routing-table 
    Route Flags: R - relay, D - download to fib
    ------------------------------------------------------------------------------
    Routing Tables: Public
             Destinations : 12       Routes : 12       

    Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface

            1.1.1.0/30  Direct  0    0           D   1.1.1.1         GigabitEthernet
    0/0/1
            1.1.1.1/32  Direct  0    0           D   127.0.0.1       GigabitEthernet
    0/0/1
            1.1.1.3/32  Direct  0    0           D   127.0.0.1       GigabitEthernet
    0/0/1
            2.2.2.0/30  ISIS-L2 15   15          D   3.3.3.2         GigabitEthernet
    0/0/0
            3.3.3.0/30  Direct  0    0           D   3.3.3.1         GigabitEthernet
    0/0/0
            3.3.3.1/32  Direct  0    0           D   127.0.0.1       GigabitEthernet
    0/0/0
            3.3.3.3/32  Direct  0    0           D   127.0.0.1       GigabitEthernet
    0/0/0
          127.0.0.0/8   Direct  0    0           D   127.0.0.1       InLoopBack0
          127.0.0.1/32  Direct  0    0           D   127.0.0.1       InLoopBack0
    127.255.255.255/32  Direct  0    0           D   127.0.0.1       InLoopBack0
         172.16.1.1/32  ISIS-L2 15   5           D   3.3.3.2         GigabitEthernet   # 选择主链路
    0/0/0
    255.255.255.255/32  Direct  0    0           D   127.0.0.1       InLoopBack0

  1. 查看IS-IS与BFD联动会话状态

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    dis isis bfd session all
    <Router A>dis isis bfd session all

                          BFD session information for ISIS(1)
                          -----------------------------------

    Peer System ID : 0030.0300.3002        Interface : GE0/0/0     
    TX : 100           BFD State : up      Peer IP Address : 3.3.3.2 
    RX : 100           LocDis : 8195       Local IP Address: 3.3.3.1 
    Multiplier : 4     RemDis : 8195       Type : L2
    Diag : No diagnostic information

    Peer System ID : 0010.0100.1002        Interface : GE0/0/1     
    TX : 1000          BFD State : up      Peer IP Address : 1.1.1.2 
    RX : 1000          LocDis : 8193       Local IP Address: 1.1.1.1 
    Multiplier : 3     RemDis : 8192       Type : L2
    Diag : No diagnostic information

    Total BFD session(s): 2

  1. 测试结果

    • Router B的端口Down

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      sys
      int g0/0/0
        shutdown

  • Router A选择备用链路

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    dis ip routing-table
    <Router A>dis ip routing-table 
    Route Flags: R - relay, D - download to fib
    ------------------------------------------------------------------------------
    Routing Tables: Public
             Destinations : 12       Routes : 12       

    Destination/Mask    Proto   Pre  Cost      Flags NextHop         Interface

            1.1.1.0/30  Direct  0    0           D   1.1.1.1         GigabitEthernet
    0/0/1
            1.1.1.1/32  Direct  0    0           D   127.0.0.1       GigabitEthernet
    0/0/1
            1.1.1.3/32  Direct  0    0           D   127.0.0.1       GigabitEthernet
    0/0/1
            2.2.2.0/30  ISIS-L2 15   20          D   1.1.1.2         GigabitEthernet
    0/0/1
            3.3.3.0/30  Direct  0    0           D   3.3.3.1         GigabitEthernet
    0/0/0
            3.3.3.1/32  Direct  0    0           D   127.0.0.1       GigabitEthernet
    0/0/0
            3.3.3.3/32  Direct  0    0           D   127.0.0.1       GigabitEthernet
    0/0/0
          127.0.0.0/8   Direct  0    0           D   127.0.0.1       InLoopBack0
          127.0.0.1/32  Direct  0    0           D   127.0.0.1       InLoopBack0
    127.255.255.255/32  Direct  0    0           D   127.0.0.1       InLoopBack0
         172.16.1.1/32  ISIS-L2 15   20          D   1.1.1.2         GigabitEthernet     # 选择备用链路
    0/0/1
    255.255.255.255/32  Direct  0    0           D   127.0.0.1       InLoopBack0
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