Lab 7.2.4: Configuring X.25 PVCs

 

 

Objectives:

  • Configure X.25 PVCs in two routers to create a functional link between them using a third router as a simulated X.25 switch.

Scenario:

Because an X.25 network is not available, you will first configure a router to act as a X.25 switch. Once the switch is configured, you will configure two routers to interface with the X.25 network. Use X.25 PVCs to create a functional link between the two routers. The branch router is a stub network, so configure a default route on the branch router side and a static route on the central router side.

Notes: 

Lab Tasks:

  1. Cable the lab as shown in the diagram. Remember to put the DCE side of the serial links on the X25Switch router side.
  2. The first router to be configured will be the X25Switch router, which will simulate our X.25 network. Log into the X25Switch router and enter global configuration mode.
  3. Configure the following information into the router:
    • Configure the hostname X25Switch on the router.
    • Turn on X.25 switching with the command:

    X25Switch(config)#x25 routing

    • Setup the static X.121 address so the router will know which interfaces to switch the X.25 packets out:

    X25Switch(config)#x25 route 311082191234 interface Serial0
    X25Switch(config)#x25 route 311082194567 interface Serial1

    • Configure each of the serial interfaces on the X.25Switch router so that they use X.25 encapsulation and set up the PVC mappings.

    X25Switch(config)#int s0
    X25Switch(config-if)#encapsulation x25 dce
    X25Switch(config-if)#x25 ltc 25
    X25Switch(config-if)#x25 htc 128
    X25Switch(config-if)#x25 pvc 1 interface serial1 pvc 4
    X25Switch(config-if)#clockrate 56000

    X25Switch(config)#int s1
    X25Switch(config-if)#encapsulation x25 dce
    X25Switch(config-if)#x25 ltc 25
    X25Switch(config-if)#x25 htc 128
    X25Switch(config-if)#x25 pvc 4 interface serial0 pvc 1
    X25Switch(config-if)#clockrate 56000


  4. Configure the branch office router serial link for X.25 encapsulation.
    • First we enable X.25 encapsulation and assign our IP address:

    BranchRouter(config)#int s0
    BranchRouter(config-if)#encapsulation x25
    BranchRouter(config-if)#ip address 192.168.3.1 255.255.255.0

    • Assign our X.121 address to this interface:

    BranchRouter(config-if)#x25 address 311082191234

    • Configure our high and low channel numbers:

    BranchRouter(config-if)#x25 ltc 25
    BranchRouter(config-if)#x25 htc 25

    Note: You may have to reboot the router before/after entering these commands.

    • Setup the X.25 mapping to the other side:

    BranchRouter(config-if)# x25 pvc 1 ip 192.168.3.2 311082194567 broadcast

    Note: You may have to reboot the router before/after entering these commands.

    • Add necessary default/static routes to facilitate successful routing.

    What command should be used to add the appropriate route on this router?

  5. Configure the serial interface on the central site router:
    • First we enable X.25 encapsulation and assign our IP address:

    CentralRouter(config)#int s0
    CentralRouter(config-if)#encapsulation x25
    CentralRouter(config-if)#ip address 192.168.3.2 255.255.255.0

    • Assign our X.121 address to this interface:

    CentralRouter(config-if)#x25 address 311082194567

    • Configure our high and low channel numbers:

    CentralRouter(config-if)#x25 ltc 25
    CentralRouter(config-if)#x25 htc 25

    • Setup the X.25 mapping to the other side:

    CentralRouter(config-if)#x25 pvc 4 ip 192.168.3.1 311082191234 broadcast

    • Add necessary default/static routes to facilitate successful routing.

    What command should be used to add the appropriate route on this router?

  6. Verify the X.25 configuration with the show interfaces serial command.

    What X.25 information is available from the show interfaces serial command when X.25 encapsulation is used?

  7. Use the sh x25 vc command to display information about the X.25 PVC.
  8. From the branch office router, ping the central site Ethernet - 192.168.2.1.

    Was this successful?
  9. From the central site router, ping the branch office Ethernet - 192.168.1.1.

Was this successful?