Frame delineation method for a generic framing procedure

1. A frame delineation method for a generic framing procedure (GFP), the method implemented using a processor and comprising:

receiving a serial data stream comprising GFP frames;

performing a frame alignment search by searching, octet by octet, the received serial data stream for an eight octet sequence comprising a first group of four octets comprising a valid Core Header;

descrambling a second group of four octets of the eight octet sequence based on a plurality of bits of the serial data stream preceding the eight octet sequence, wherein the descrambling is performed during the frame alignment search, and wherein the descrambling is in response to determining that the first group of four octets of the eight octet sequence comprises a valid Core Header and to determining that a payload length indicator of the valid Core Header is not equal to zero; and

delineating, during the frame alignment search, GFP frames from the received serial data stream in response to determining that the second group of four octets comprises a valid descrambled Type Header.

2. The frame delineation method of claim 1 , further comprising delineating, during a frame alignment search, GFP frames from the received serial data stream in response to determining that a first group of four octets of a second eight octet sequence comprises a first valid Core Header and in response to determining that a second group of four octets of the second eight octet sequence comprises a second valid Core Header.

3. The frame delineation method of claim 1 , further comprising descrambling the second group of four octets of the eight octet sequence based on forty three bits of the serial data stream that immediately precede the eight octet sequence.

4. The frame delineation method of claim 3 , wherein the descrambling is performed using a free-running X 75 +1 self-synchronous descrambler.

5. The frame delineation method of claim 4 , further comprising:

descrambling, using a X 43 +1 GFP payload descrambler, a portion of a payload of a GFP frame that immediately follows the second group of four octets of the eight octet sequence; and

initializing the X 43 +1 GFP payload descrambler utilizing a combination of information from a Type Header of the second group of four octets of the eight octet sequence and eleven bits that immediately precede the eight octet sequence prior to the X 43 +1 descrambler descrambling the portion of a payload of the GFP frame that immediately follows the second group of four octets of the eight octet sequence.

6. A frame delineation method for a generic framing procedure (GFP), the method implemented using a processor and comprising:

receiving a serial data stream comprising GFP frames;

performing a frame alignment search comprising searching the received serial data stream comprising GFP frames to locate a GFP frame having a valid Core Header;

descrambling a Type Header of the GFP frame based on a plurality of bits of the serial data stream preceding the GFP frame, wherein the descrambling is performed during the frame alignment search, and wherein the descrambling is in response to determining that a payload length indicator of the valid Core Header is not equal to zero; and

delineating, during the frame alignment search, GFP frames from the serial data stream based on the valid Core Header of the GFP frame and based on the descrambled Type Header of the GFP frame when the descrambled Type Header is valid.

7. The frame delineation method of claim 6 , further comprising descrambling the Type Header of the GFP frame based on forty three bits of the serial data stream that immediately precede the GFP frame.

8. The frame delineation method of claim 7 , wherein the descrambling is performed using a free running X 75 +1 descrambler.

9. The frame delineation method of claim 8 , further comprising:

descrambling, using a X 43 +1 GFP payload descrambler, a portion of the GFP frame; and

initializing the X 43 +1 GFP payload descrambler utilizing information from the Type Header of the GFP frame and the last eleven bits preceding the GFP frame prior to the X 43 +1 GFP payload descrambler descrambling the portion of a payload of the GFP frame that immediately follows the Type Header of the GFP frame.

10. A frame delineation method for a generic framing procedure (GFP), the method implemented using a processor and comprising:

receiving a serial data stream comprising GFP frames from a network;

serial-to-parallel converting the received serial data stream;

performing a frame alignment search comprising reading an eight octet sequence from the serial-to-parallel converted data stream;

determining whether a first group of four octets of the eight octet sequence comprises a valid Core Header;

when the first group of four octets of the eight octet sequence comprises a valid Core Header, determining a payload length indicator of the valid Core Header;

when the payload length indicator is not equal to zero, descrambling a second group of four octets of the eight octet sequence based on a plurality of bits of the serial data stream preceding the eight octet sequence and determining whether the descrambled second group of four octets of the eight octet sequence comprises a valid Type Header, wherein the descrambling is performed during the frame alignment search; and

delineating, during the frame alignment search, GFP frames from the received serial data stream when the second group of four octets of the eight octet sequence comprises the valid descrambled Type Header.

11. The frame delineation method of claim 10 , wherein the descrambling the second group of four octets of the eight octet sequence is based on forty three bits of the serial data stream that immediately precede the eight octet sequence.

12. The frame delineation method of claim 10 , wherein the descrambling is performed using a free running X 75 +1 descrambler.