Frame-Relay Back to Back

Posted by July 14, 2010 in Frame Relay

Scenario

You are working for a huge international car company as the senior network engineer. You need to connect a new branch office to the Headquarters. Since the company believes in proven technology they want you to connect the 2 sites by using Frame-Relay without a Frame-Relay switch.

Goal:

  • You are not allowed to use the ‘Frame-Relay Switching’ command on any router.
  • Configure Frame-Relay encapsulation on both Routers.
  • Configure the IP addresses as specified in the topology picture.
  • Use the DLCI numbers as specified in the topology picture.
  • Achieve IP connectivity across the frame-relay link.

IOS:

c3640-jk9s-mz.124-16.bin

Topology:

Frame-Relay Back to Back

Video Solution:

Configuration Files

You need to register to download the GNS3 topology file. (Registration is free!)

Once you are logged in you will find the configuration files right here.

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10 Comments

  1. Hi

    If we are connecting Point-to-Point connection and enable the encapsulation as FR and in this case what is the use DLCI.Please explain

    Thanks
    KD

  2. Good question!

    Keep in mind the DLCI is a layer 2 identifier for frame-relay, just like a MAC address is for Ethernet.

    Frame-relay needs to map IP addresses (layer3) to a DLCI (layer2), and you are unable to use an empty value for DLCI. The DLCI’s make up the ‘logical link’ aka the PVC.

    You also don’t send Ethernet frames on a LAN with empty mac addresses, even if it’s p2p. If you want to get funky you could create multiple PVC’s over this single physical p2p link…

    Kind Regards,

    Rene

  3. Maybe I’m wrong but the lab says to use the DLCI numbers specified (102 and 201) but in a back to back frame relay connection, don’t the DLCI numbers need to be the same?

    I tried this out and could only get it to work when the DLCI numbers were the same. Am I missing something?

  5. interface Serial0/0
    no ip address
    encapsulation frame-relay
    no keepalive
    serial restart-delay 0
    !
    interface Serial0/0.1 point-to-point
    ip address 192.168.12.2 255.255.255.252
    frame-relay interface-dlci 102

  6. Bumblebee

    interface Serial0/0
    no ip address
    encapsulation frame-relay
    no keepalive
    serial restart-delay 0
    !
    interface Serial0/0.1 point-to-point
    ip address 192.168.12.1 255.255.255.252
    frame-relay interface-dlci 102
    [b][/b][u][/u]

  7. bumblebee#
    interface Serial0/0
    ip address 192.168.12.1 255.255.255.252
    encapsulation frame-relay
    no keepalive
    serial restart-delay 0
    frame-relay map ip 192.168.12.2 102
    frame-relay interface-dlci 102
    no frame-relay inverse-arp
    !
    ironhide#
    interface Serial0/0
    ip address 192.168.12.2 255.255.255.252
    encapsulation frame-relay
    no keepalive
    serial restart-delay 0
    frame-relay map ip 192.168.12.1 102
    frame-relay interface-dlci 102
    no frame-relay inverse-arp
    !

Comments are closed.