Configuration Tasks

To configure a Cisco HDLC interface:

  1. Configure the physical interface on which you want to configure Cisco HDLC.
    host1(config)#interface serial 3/1:2/1
  2. Select Cisco HDLC as the encapsulation method for the interface.
    host1(config-if)#encapsulation hdlc
  3. Assign a local IP address to the interface.
    host1(config-subif)#ip address
  4. (Optional) Use the appropriate show hdlc interface to verify that the configuration changes are correct.

encapsulation hdlc

interface serial

ip address

Optional Tasks

The following tasks are optional.

  1. Configure the SLARP keepalive interval.
    host1(config-if)#hdlc keepalive 10
  2. Enable loopback detection on an interface.
    host1(config-if)#hdlc down-when-looped
  3. Disable an interface.
    host1(config-if)#hdlc shutdown

hdlc down-when-looped

hdlc keepalive

hdlc shutdown

Configuration Example

This example shows how to configure Cisco HDLC over an unchannelized DS3 interface on a cOCx/STMx line module. The example shows the complete configuration procedure, from configuring the SONET interface to assigning an IP address to the Cisco HDLC interface.

  1. Create or select a virtual router, vr1.
    host1(config)#virtual-router vr1
  2. Configure SONET controller, slot 13, port 0.
    host1:vr1(config)#controller sonet 13/0
  3. Set the SONET clock source to internal.
    host1:vr1(config-controll)#clock source internal module
  4. Create an OC1 path.
    host1:vr1(config-controll)#path 1 oc1 1
  5. Create an unchannelized DS3 interface.
    host1:vr1(config-controll)#path 1 ds3 1 unchannelized
  6. Set the DS3 interface clock source to internal.
    host1:vr1(config-controll)#path 1 ds3 1 clock source internal module
  7. Exit Controller Configuration mode.
  8. Create or select a serial interface over the DS3 interface.
    host1:vr1(config)#interface serial 13/0:1/1
  9. Set the encapsulation to Cisco HDLC.
    host1:vr1(config-if)#encapsulation hdlc
  10. Enable loopback detection on the interface.
    host1:vr1(config-if)#hdlc down-when-looped
  11. Assign an IP address to the interface.
    host1:vr1(config-if)#ip address