Interfacing apparatus and method for adapting Ethernet directly to physical channel

A data transmission method for transmitting data packets from an upper layer side device to a lower layer side device, comprising steps of:

• receiving and buffering the data packets from said upper layer side device, adapting the rate of said upper layer side device to the rate of said lower layer side device, and converting said data packets to a first type of frames;
• encapsulating said first type of frames to form a second type of frames containing a SAPI field including a SAPI identifier and an information field including said data packets;
• encapsulating said second type of frames into a payload portion, inserting appropriate overheads corresponding to said data packets, so as to form a third type of frames;
• and
• outputting said third type of frames to said lower layer side device,
• wherein said upper layer is Ethernet MAC/GMAC layer, said first type of frames are MAC/GMAC frames, said second type of frames are LAPS frames, and the third type of frames are SDH/SONET frames.

A data transmission apparatus for transmitting data packets formed by a first type of frames from a lower layer side device to an upper layer side device, comprising:

• a second receiving means for receiving the data packets from said lower layer side device;
• a de-framing means for removing the overheads of said first type of frames;
• a third processing means for extracting a SAPI field and the data contained in the information field from the payload portion of said first type of frames, to form a second type of frames;
• a determining means for comparing the value of the SAPI field with a preset value, and determining to output the extracted data as it be if the value of the SAPI field data equals to said preset value;
• a fourth processing means for converting said second type of frames to a third type of frames corresponding to in said data packets;
• and
• a second transmitting means for transmitting the extracted data packets to said upper layer side device.

A data transmission method for transmitting data packets formed by a first type of frames from a lower layer side device to an upper layer side device, comprising steps of:

• receiving the data packets from said lower layer side device;
• removing the overheads of said first type of frames;
• extracting a SAPI field and the data contained in the information field from the payload portion of said first type of frames, to form a second type of frames;
• comparing the value of the SAPI field with a preset value, and determining to output the extracted data as it be if the value of the SAPI field data equals to said preset value;
• converting said second type of frames to a third type of frames corresponding to in said data packets;
• and
• transmitting the extracted data packets to said upper layer side device,
• wherein said upper layer is Ethernet MAC layer, said first type of frames are MAC frames, said second type of frames are LAPS frames, and the third type of frames are SDH/SONET frames.

A data interfacing apparatus for transmitting data packets between a upper layer side device and a lower layer side device, comprising:

• a first receiving means for receiving the data packets from said upper layer side device, and converting said data packets to a first type of frames;
• a first processing means for encapsulating said first type of frames to form a second type of frames containing a SAPI field including a SAPI identifier and an information field including said data packets;
• a second processing means for encapsulating said second type of frames into a payload portion, inserting appropriate overheads corresponding to said data packets, so as to form a third type of frames;
• a first transmitting means for outputting said third type of frames to the lower layer side device;
• a second receiving means for receiving the data packets from said lower layer side device;
• a de-framing means for removing the overheads of said first type of frames;
• a third processing means for extracting a SAPI field and the data contained in the information field from the payload portion of said first type of frames, to form said second type of frames;
• a determining means for comparing the value of the SAPI field with a preset value, and determining to output the extracted data as is, if the value of the SAPI field data equals to said preset value;
• a fourth processing means for converting said second type of frames to a third type of frames corresponding to in said data packets;
• and
• a second transmitting means for transmitting the extracted data packets to said upper layer side device.