X.25 Configuration Task List
To configure X.25, complete the tasks in the following sections. The interface, datagram transport, and
routing tasks are divided into sections based on how common the feature is and how often it is used.
Those features and parameters that are less common are found in the sections “Configuring Additional
X.25 Interface Parameters,” “Configuring Additional X.25 Datagram Transport Features,” and
“Configuring Additional X.25 Routing Features.” LAPB frame parameters can be modified to optimize
X.25 operation, as described earlier in this chapter. All these features can coexist on an X.25 interface.
• Configuring an X.25 Interface (Required)
• Configuring Additional X.25 Interface Parameters (Optional)
Command Purpose
Step 1 Router(config)# interface serial number Enters interface configuration mode.
Step 2 Router(config-if)# no ip address Assigns no IP address to the interface.
Step 3 Router(config-if)# encapsulation lapb multi Configures multiprotocol LAPB encapsulation.
Step 4 Router(config-if)# bridge-group bridge-group Assigns the interface to a bridge group.
Step 5 Router(config)# bridge bridge-group protocol {ieee | dec} Defines the type of Spanning-Tree Protocol.

Cisco IOS Wide-Area Networking Configuration Guide
• Configuring an X.25 Datagram Transport (Optional)
• Configuring Additional X.25 Datagram Transport Features (Optional)
• Configuring X.25 Routing (Required)
• Configuring Additional X.25 Routing Features (Optional)
• Configuring DNS-Based X.25 Routing (Optional)
• Configuring X.25 over Frame Relay (Annex G) (Optional)
• Configuring CMNS Routing (Optional)
• Configuring Priority Queueing or Custom Queueing for X.25 (Optional)
• Configuring X.25 Closed User Groups (Optional)
• Configuring DDN or BFE X.25 (Optional)
• Configuring X.25 Remote Failure Detection (Optional)
• Creating X.29 Access Lists (Optional)
• Creating an X.29 Profile Script (Optional)
• Monitoring and Maintaining LAPB and X.25 (Optional)