When you enable fragmentation, you can specify a maximum payload size of the resulting fragments. If the maximum payload size is not specified, the default value of 52 bytes is used. When enabled, fragmentation begins when the portion of the packet that has not been transmitted in previous fragments exceeds the configured maximum payload size. The fragmentation process continues until the entire packet has been transmitted. Frames that do not exceed the configured maximum payload size are not fragmented.
If you disable fragmentation, all packets transmitted by the Frame Relay subinterface are transmitted intact.