DIS election configuration

Network requirements

As shown in Figure 64, Switch A, B, C, and D reside in IS-IS area 10 on a broadcast network (Ethernet). Switch A and Switch B are Level-1-2 switches, Switch C is a Level-1 switch, and Switch D is a Level-2 switch.

Change the DIS priority of Switch A to make it elected as the Level-1-2 DIS router.

Figure 64: Network diagram for DIS selection

Configuration procedure

  1. Configure an IP address for each interface. (Details not shown.)

  2. Enable IS-IS:

    # Configure Switch A.

    <SwitchA> system-view
    [SwitchA] isis 1
    [SwitchA-isis-1] network-entity 10.0000.0000.0001.00
    [SwitchA-isis-1] quit
    [SwitchA] interface vlan-interface 100
    [SwitchA-Vlan-interface100] isis enable 1
    [SwitchA-Vlan-interface100] quit
    

    # Configure Switch B.

    <SwitchB> system-view
    [SwitchB] isis 1
    [SwitchB-isis-1] network-entity 10.0000.0000.0002.00
    [SwitchB-isis-1] quit
    [SwitchB] interface vlan-interface 100
    [SwitchB-Vlan-interface100] isis enable 1
    [SwitchB-Vlan-interface100] quit
    

    # Configure Switch C.

    <SwitchC> system-view
    [SwitchC] isis 1
    [SwitchC-isis-1] network-entity 10.0000.0000.0003.00
    [SwitchC-isis-1] is-level level-1
    [SwitchC-isis-1] quit
    [SwitchC] interface vlan-interface 100
    [SwitchC-Vlan-interface100] isis enable 1
    [SwitchC-Vlan-interface100] quit
    

    # Configure Switch D.

    <SwitchD> system-view
    [SwitchD] isis 1
    [SwitchD-isis-1] network-entity 10.0000.0000.0004.00
    [SwitchD-isis-1] is-level level-2
    [SwitchD-isis-1] quit
    [SwitchD] interface vlan-interface 100
    [SwitchD-Vlan-interface100] isis enable 1
    [SwitchD-Vlan-interface100] quit
    

    # Display information about IS-IS neighbors of Switch A.

    [SwitchA] display isis peer
    
                              Peer information for ISIS(1)
                              ----------------------------
      System Id: 0000.0000.0002
      Interface: Vlan-interface100       Circuit Id: 0000.0000.0003.01
      State: Up     HoldTime: 21s        Type: L1(L1L2)     PRI: 64
    
      System Id: 0000.0000.0003
      Interface: Vlan-interface100       Circuit Id: 0000.0000.0003.01
      State: Up     HoldTime: 27s        Type: L1           PRI: 64
    
      System Id: 0000.0000.0002
      Interface: Vlan-interface100       Circuit Id: 0000.0000.0004.01
      State: Up     HoldTime: 28s        Type: L2(L1L2)     PRI: 64
    
      System Id: 0000.0000.0004
      Interface: Vlan-interface100       Circuit Id: 0000.0000.0004.01
      State: Up     HoldTime: 30s        Type: L2          PRI: 64
    
    

    # Display information about IS-IS interfaces of Switch A.

    [SwitchA] display isis interface
    
                           Interface information for ISIS(1)
                           ---------------------------------
    Interface: Vlan-interface100
    Id      IPV4.State      IPV6.State    MTU    Type    DIS
    001        Up             Down       1497    L1/L2   No/No
    

    # Display information about IS-IS interfaces of Switch C.

    [SwitchC] display isis interface
    
                           Interface information for ISIS(1)
                           ---------------------------------
    Interface: Vlan-interface100
    Id      IPV4.State      IPV6.State    MTU    Type    DIS
    001         Up            Down        1497   L1/L2   Yes/No
    

    # Display information about IS-IS interfaces of Switch D.

    [SwitchD] display isis interface
    
                           Interface information for ISIS(1)
                           ---------------------------------
    Interface: Vlan-interface100
    Id      IPV4.State       IPV6.State   MTU     Type     DIS
    001         Up             Down       1497    L1/L2    No/Yes
    

    By using the default DIS priority, Switch C is the Level-1 DIS, and Switch D is the Level-2 DIS. The pseudonodes of Level-1 and Level-2 are 0000.0000.0003.01 and 0000.0000.0004.01.

  3. Configure the DIS priority:

    # Configure the DIS priority on Switch A.

    [SwitchA] interface vlan-interface 100
    [SwitchA-Vlan-interface100] isis dis-priority 100
    [SwitchA-Vlan-interface100] quit
    

    # Display IS-IS neighbors on Switch A.

    [SwitchA] display isis peer
    
                              Peer information for ISIS(1)
                              ----------------------------
      System Id: 0000.0000.0002
      Interface: Vlan-interface100       Circuit Id: 0000.0000.0001.01
      State: Up     HoldTime: 21s        Type: L1(L1L2)     PRI: 64
    
      System Id: 0000.0000.0003
      Interface: Vlan-interface100       Circuit Id: 0000.0000.0001.01
      State: Up     HoldTime: 27s        Type: L1           PRI: 64
    
    
      System Id: 0000.0000.0002
      Interface: Vlan-interface100       Circuit Id: 0000.0000.0001.01
      State: Up     HoldTime: 28s        Type: L2(L1L2)     PRI: 64
    
      System Id: 0000.0000.0004
      Interface: Vlan-interface100       Circuit Id: 0000.0000.0001.01
      State: Up     HoldTime: 30s        Type: L2           PRI: 64
    
    

    # Display information about IS-IS interfaces on Switch A.

    [SwitchA] display isis interface
    
                           Interface information for ISIS(1)
                           ---------------------------------
    Interface: Vlan-interface100
    Id      IPV4.State      IPV6.State      MTU    Type   DIS
    001         Up             Down         1497   L1/L2  Yes/Yes
    

    After the DIS priority configuration, Switch A becomes the Level-1-2 DIS, and the pseudonode is 0000.0000.0001.01.

    # Display information about IS-IS neighbors and interfaces of Switch C.

    [SwitchC] display isis peer
    
                              Peer information for ISIS(1)
                              ----------------------------
      System Id: 0000.0000.0002
      Interface: Vlan-interface100       Circuit Id: 0000.0000.0001.01
      State: Up     HoldTime: 25s        Type: L1           PRI: 64
    
      System Id: 0000.0000.0001
      Interface: Vlan-interface100       Circuit Id: 0000.0000.0001.01
      State: Up     HoldTime: 7s         Type: L1           PRI: 100
    
    [SwitchC] display isis interface
    
                           Interface information for ISIS(1)
                           ---------------------------------
    Interface: Vlan-interface100
    Id      IPV4.State          IPV6.State    MTU    Type   DIS
    001         Up                 Down       1497   L1/L2  No/No
    

    # Display information about IS-IS neighbors and interfaces of Switch D.

    [SwitchD] display isis peer
    
                              Peer information for ISIS(1)
                              ----------------------------
      System Id: 0000.0000.0001
      Interface: Vlan-interface100       Circuit Id: 0000.0000.0001.01
      State: Up     HoldTime: 9s         Type: L2           PRI: 100
    
      System Id: 0000.0000.0002
      Interface: Vlan-interface100       Circuit Id: 0000.0000.0001.01
      State: Up     HoldTime: 28s        Type: L2           PRI: 64
    
    [SwitchD] display isis interface
    
                           Interface information for ISIS(1)
                           ---------------------------------
    Interface: Vlan-interface100
    Id      IPV4.State          IPV6.State    MTU   Type    DIS
    001         Up                 Down       1497  L1/L2   No/No