Connecting routers through POS interfaces across a Frame Relay network

Network requirements

As shown in Figure 3, use POS subinterfaces to connect Router A to Router B and Router C across a Frame Relay network. The routers are all DTEs on the Frame Relay network.

Figure 3: Network diagram

Configuration procedure

  1. Configure Router A:

    # Set the clock mode to slave on POS 2/1/1.

    <RouterA> system-view
    [RouterA] interface pos 2/1/1
    [RouterA-Pos2/1/1] clock slave
    

    # Enable Frame Relay on POS 2/1/1.

    [RouterA-Pos2/1/1] link-protocol fr
    

    # Configure POS 2/1/1 as DTE.

    [RouterA-Pos2/1/1] fr interface-type dte
    [RouterA-Pos2/1/1] quit
    

    # Create subinterface 1 on POS 2/1/1 and assign an IP address to it.

    [RouterA] interface pos 2/1/1.1
    [RouterA-Pos2/1/1.1] ip address 10.10.10.1 255.255.255.0
    

    # Assign a virtual circuit with DLCI 50 to subinterface 1.

    [RouterA-Pos2/1/1.1] fr dlci 50
    [RouterA-Pos2/1/1.1-fr-dlci-50] quit
    

    # Map DLCI 50 to the peer IP address 10.10.10.2.

    [RouterA-Pos2/1/1.1] fr map ip 10.10.10.2 50
    

    # Set the MTU to 1500 for subinterface 1.

    [RouterA-Pos2/1/1.1] mtu 1500
    [RouterA-Pos2/1/1.1] quit
    

    # Create subinterface 2 on POS 2/1/1 and assign an IP address to it.

    [RouterA] interface pos 2/1/1.2
    [RouterA-Pos2/1/1.2] ip address 20.10.10.1 255.255.255.0
    

    # Assign a virtual circuit with DLCI 60 to subinterface 2.

    [RouterA-Pos2/1/1.2] fr dlci 60
    [RouterA-Pos2/1/1.2-fr-dlci-60] quit
    

    # Map DLCI 60 to the peer IP address 20.10.10.2.

    [RouterA-Pos2/1/1.2] fr map ip 20.10.10.2 60
    

    # Set the MTU to 1500 for subinterface 2.

    [RouterA-Pos2/1/1.2] mtu 1500
    [RouterA-Pos2/1/1.2] quit
    
  2. Configure Router B:

    # Set the clock mode to slave on POS 2/1/1.

    [RouterB] interface pos 2/1/1
    [RouterB-Pos2/1/1] clock slave
    

    # Enable Frame Relay on POS 2/1/1.

    [RouterB-Pos2/1/1] link-protocol fr
    

    # Configure POS 2/1/1 as DTE.

    [RouterB-Pos2/1/1] fr interface-type dte
    

    # Assign an IP address to POS 2/1/1.

    [RouterB-Pos2/1/1] ip address 10.10.10.2 255.255.255.0
    

    # Assign a virtual circuit with DLCI 70 to POS 2/1/1.

    [RouterB-Pos2/1/1] fr dlci 70
    [RouterB-Pos2/1/1-fr-dlci-70] quit
    

    # Map DLCI 70 to the peer IP address 10.10.10.1.

    [RouterB-Pos2/1/1] fr map ip 10.10.10.1 70
    

    # Set the MTU to 1500 for POS 2/1/1.

    [RouterB-Pos2/1/1] mtu 1500
    
  3. Configure Router C in the same way Router B is configured. (Details not shown.)

Verifying the configuration

# Verify the POS interface settings.

<RouterA> display interface pos

# Verify that Router A and Router B can ping each other. (Details not shown.)

# Verify that Router A and Router C can ping each other. (Details not shown.)