Frame Relay Encapsulation

If you are using a router, Frame Relay can be easily set up only on the interfaces that it supports without any hesitation; it is mostly supported on synchronous serial interfaces. Only a single command is required to configure the Frame Relay on the serial line system.
If you want to enable the Frame Relay for a serial interface following are the steps:

Step 1:

Go to the configuration mode and change the configuration to you choice.

Step 2:

Select any of the Frame Relay encapsulation, either Cisco or IETF encapsulations. If you do not select any of them at the time of configuration then Cisco is selected automatically.

If you use the “no” command in the configuration mode, then the Frame Relay encapsulation is removed and the serial interface is set to the default interface of High Level Data Link Control encapsulation. Other than the Frame Relay encapsulations are also removed when the “no” command is used.

It should be kept in mind that the Frame Relay encapsulation only works with some of the supported interfaces to which it is configured easily. At this time it can be configured with synchronous serial interface, High Speed Serial Interface (HSSI) and packets over SONET (POS) interfaces. Other than these interfaces it is impossible to configure the setup if you try to do so the error message will be displayed that will tell you that this is not supportive interface for this setup.

If you are connecting a Cisco router to non Cisco devices across the network then you have to use the IETF Frame Relay encapsulation. The IETF Frame Relay encapsulation has the flexibility to connect with other devices of different makers, it is universal adapter. If you have forgotten to write the encapsulation frame-relay command and have not entered the specified the keyword then it will connect to the Cisco interface by default.