Leased Line Access Switch Settings

To configure a leased line on an access switch, you need to set up the physical interface, apply the correct encapsulation and authentication, assign IP addresses, and verify connectivity.

Step 1: Prepare the Access Switch

Before configuring the leased line, ensure the switch is operational:

• Power on the switch and verify indicator lights.
• Connect to the switch console using a rollover cable and terminal software like PuTTY at 9600 baud rate.
• Set a hostname and management IP address on the switch for administrative access.
• Confirm VLAN and trunking configurations if the leased line will traverse multiple VLANs .

Step 2: Identify the Leased Line Type

Leased lines can be E1, T1, or ISDN PRI, depending on your network requirements:

• E1 leased line: Typically uses PPP encapsulation and CHAP authentication.
• ISDN PRI leased line: Suitable for high-speed, long-term data exchange between branches and headquarters .
• Determine the termination type and ensure the correct equipment is available at both ends .

Step 3: Configure the Physical Interface

• Access the interface connected to the leased line (e.g., E1/CE1).
• Set the interface mode according to the leased line type:
  • For E1: interface E1/CE1 and configure timeslots as required.
  • For ISDN PRI: configure the PRI interface with the appropriate channel group.
• Enable the interface and verify the physical and link layer status using commands like display interface serial 1/0/0:0 .

Step 4: Apply Encapsulation and Authentication

• Configure PPP encapsulation on the interface: encapsulation ppp.
• Set up CHAP authentication with a username and password: ppp chap user ppp chap password cipher .
• Ensure both ends of the leased line use matching authentication credentials.

Step 5: Assign IP Addresses

• Assign IP addresses to the interface according to your network plan.
• For managed leased lines, the last usable IP in the assigned range is often used as the gateway for the network .
• Verify subnet masks and routing to ensure proper communication between branch and headquarters.

Step 6: Verify Connectivity

• Test the connection by pinging the remote device.
• Check interface status and logs to confirm the link is up and stable.
• Ensure that any VLAN or routing configurations allow traffic to pass over the leased line.

Step 7: Optional Backup and Redundancy

• Consider configuring a backup Ethernet leased line or diverse path for redundancy.
• Ensure failover mechanisms are tested to maintain connectivity in case of primary line failure . By following these steps, you can successfully configure a leased line on an access switch, ensuring a permanent, reliable connection between your branch and central network. Proper encapsulation, authentication, and IP addressing are critical for secure and efficient data transmission.