Lab 7.2.3: Configuring X.25 SVCs

Objectives:

  • Configure X.25 SVCs 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 SVCs 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 X25 Switch router side.
  2. The first router to be configured will be the X25 Switch router, which will simulate our X.25 network. Log into the X25 Switch router and enter global configuration mode.
  3. Configure the following information into the router:
    • Configure the hostname X25 Switch on the router.
    • Turn on X.25 switching with the command:

    X25Switch(config)#x25 routing

    • Configure each of the serial interfaces on the X.25 Switch router so that they use X.25 encapsulation.

    X25Switch(config)#int s0
    X25Switch(config-if)#encapsulation x25 dce
    X25Switch(config-if)#clockrate 56000

    X25Switch(config)#int s1
    X25Switch(config-if)#encapsulation x25 dce
    X25Switch(config-if)#clockrate 56000

    • 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

    These commands will statically route the X.121 addresses out the specified interfaces.

  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

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

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

Add necessary default/static routes to facilitate successful routing.

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

  1. 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

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

CentralRouter(config-if)#x25 map 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?

  1. 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?

  2. From the branch office router, ping the central site Ethernet - 192.168.2.1.

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

Was this successful?