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
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
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
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.)