Specifications

6-15
Cisco XR 12000 Series Router SIP and SPA Software Configuration Guide, Release 3.2
Release 3.2, OL-6396-01, Rev.A1 January 9, 2006
Chapter 6 Configuring POS SPAs on Cisco IOS XR Software
Configuration Tasks
Configuring Cisco HDLC on a POS Interface
Cisco High-Level Data Link Controller (HDLC) is Cisco’s proprietary protocol for sending data over
synchronous serial links using HDLC. Cisco HDLC also provides a simple control protocol called Serial
Line Address Resolution Protocol (SLARP) to maintain serial link keepalives. HDLC is the default
encapsulation for POS interfaces under Cisco IOS XR software.
Perform this task to configure the Cisco HDLC encapsulation type on a POS interface.
Prerequisites
To use the keepalive command, you must be in a user group associated with a task group that includes
the proper task IDs for HDLC commands. To use the encapsulation hdlc command, you must be in a
user group associated with a task group that includes the proper task IDs for interface and HDLC
commands.
Task IDs for commands are listed in the Cisco IOS XR Task ID Reference Guide.
Note Cisco HDLC is enabled by default for POS configurations on the Cisco XR 12000 Series Router.
Cisco HDLC keepalives are useful for monitoring the link state. Periodic keepalives are sent to and
received from the peer at a frequency determined by the keepalive value. If an acceptable keepalive
response is not received from the peer, the link makes the transition to the down state. As soon as an
acceptable keepalive response is obtained from the peer or if keepalive is disabled, the link makes the
transition to the up state.
If three keepalives are sent to the peer and no response is received from peer, then the link makes the
transition to the down state.
The Serial Line Address Resolution Protocol (SLARP) packets sent to the peer after keepalive has been
configured can be displayed using the debug chdlc slarp packet and other Cisco HDLC debug
commands.
Summary Steps
1. configure
2. interface type number
3. ipv4 address ip-address
4. encapsulation [hdlc | ppp]
Step 11
show interfaces type number
Example:
RP/0/0/CPU0:router# show interfaces pos 0/1/0/0
(Optional) Displays the interface configuration.
Step 12
show running-config
Example:
RP/0/0/CPU0:router# show running-config
(Optional) Displays the configuration information currently
running on the router.
Command or Action Purpose