Patent ID: 7593399

Claim:
A method of generating a plurality of layer 1 frames, having a common frame format, from a plurality of types of layer 2 data, including Synchronous Transfer Mode (STM) signals, Asynchronous Transfer Mode (ATM) cells, primary Internet Protocol (IP) packets, and best effort IP packets, the method comprising: forming a payload for a layer 1 frame that includes the data of a layer 2 frame; forming, based on a type of the data of the layer 2 frame, a layer 1 frame header including: a packet length field to indicate a size of a payload portion of the layer 1 frame, a priority field to indicate a priority of the layer 1 frame, a protocol field to identify a protocol of the payload based on the type of the data in the layer 2 frame, a frame mode field to indicate a correspondence between the layer 1 frame and the layer 2 frame included within the payload, a stuff field to indicate whether stuff data is contained in the layer 1 frame, and a cyclic redundancy check (CRC) field to indicate a CRC result; and outputting the layer 1 frames in the common frame format, where the layer 1 frames that include the STM layer 2 data are periodically output, and when an idle transfer space immediately precedes a particular layer 1 frame that includes the STM layer 2 data being output: inserting a dummy frame into the idle transfer space when the idle transfer space is sufficient to accommodate at least a minimum-length dummy frame, and inserting, when the idle transfer space is not sufficient to accommodate the minimum-length dummy frame, a partitioned layer 1 frame that includes the best effort IP packets or a layer 1 frame that includes the best effort IP packets and the stuff data into the idle transfer space, where a length of the stuff data is smaller than a sum of a length of the layer 1 frame header and the CRC field.