High accuracy 1588 timestamping over high speed multi lane distribution physical code sublayers
View Patent ↗A physical layer device provides for synchronization of clocks in a communication network. A place holder for an alignment marker is inserted into a frame to be transmitted. Once the placeholder alignment marker is inserted into the frame, no additional data is added to the frame. Transmission of the frame including the placeholder alignment marker may also be delayed to allow data processing in subsequent blocks within a transmit block to complete prior to further processing of the frame including the placeholder alignment marker (e.g., timestamping, MACSec, etc.) to improve timing accuracy with a multi lane distribution environment.
1. A physical layer communication device, comprising:
a rate adaptation block to receive and buffer frames to be transmitted;
a timestamp engine, coupled to the rate adaptation block, to timestamp some of the frames by adding to the some of the frames an indication of a predicted time that the frame is transmitted; and
a placeholder insertion block, coupled to the timestamp engine, to insert alignment marker placeholders into the frames, the placeholder insertion block additionally providing to the timestamp engine an indication of a level of fill of buffers in the placeholder insertion block;
wherein the timestamp engine delays timestamping of the some of the frames when the indication of the level of fill of the buffers in the placeholder insertion block indicates that the buffers are not empty.
2. The device of claim 1 , further comprising a media access control security (MACSec) block, coupled between the timestamp engine and the placeholder insertion block, the MACSec block including an encryption engine for encrypting the frames.
3. The device of claim 2 , wherein the timestamp engine accounts for delays related to the MACSec block in timestamping the some of the frames.
4. The device of claim 1 , wherein the placeholder insertion block is configured to insert the alignment marker placeholder once for every 16,000 blocks, wherein the alignment marker placeholder is 64 bits.
5. The device of claim 4 , wherein each of the blocks comprises 66 bits.
6. A method of performing timestamp related processing for frames subject to media access control security (MACSec) processing, comprising:
inserting idle symbols until buffers utilized for MACSec processing are empty;
inserting a timestamp into a data frame once the buffers utilized for MACSec processing are empty;
performing MACSec processing on the timestamped data frame; and
inserting a placeholder for an alignment marker at a predetermined location within the MACSec processed data frame.
7. The method of claim 6 , wherein the placeholder is inserted at a fixed rate.
8. The method of claim 6 , wherein the alignment marker comprises a lane marker for a multilane distribution environment.
9. The method of claim 6 , wherein the timestamp is a correction value.