PPP is the default encapsulation on a WAN port. If the encapsulation has been changed to frame relay and you want to restore PPP encapsulation, or to change the PPP parameters:
Procedure
Ensure that you are in the context of a serial interface that is defined on the port.
If you are not in the context of a serial interface, use the interface serial command. To view all Serial interfaces that are defined, use the show interfaces serial command.
If the interface is not already configured to use PPP encapsulation, enter encapsulation ppp to change the encapsulation to PPP.
Optional Change the queuing mode of the interface.
Use the following commands to change the interface parameters:
ip address. Configure the IP address and subnet mask of the interface.
ppp timeout ncp. Set the maximum time to wait for the network layer to negotiate. If this time is exceeded, the Gateway restarts the PPP session.
ppp timeout retry. Set the maximum time to wait for a response during PPP negotiation.
keepalive. Enable keepalive or change the interval to which keepalive is set. When activated, keepalive performs the initial negotiation and sends health checks at defined intervals to the other side of the interface. To deactivate keepalive, use the no form of the command or set the health check interval to 0.
Enter exit to return to general context.
The prompt returns to:
Gxxx-001(super)#
Test the WAN configuration.
Enter copy running-config startup-config to save the configuration.
