Simplified data link protocol processor

Abstract

A simplified data link protocol which may be implemented in a very high-speed transmission system, e.g., SONET, processes a datagram received from an IP facility according to QoS considerations and scrambles a datagram before it is again scrambled by a transmission system, e.g., a SONET transmitter, to ensure that the pattern of a user's data does not match the transmission scrambling pattern. The data link protocol scrambler also employs a novel synchronization scheme. We also use a pointer system which identifies the location of a datagram in a frame to eliminate flags and the need to process user data to ensure that it does not contain and a boundary flag.

1. Apparatus for processing, in accordance with a simplified data link protocol, a datagram received from an Internet facility and supplying the processed datagram to Synchronous Optical NETwork (SONET) apparatus for transmission over an optical path, said datagram being formed from a plurality of data bytes and being associated with a predetermined quality of service, said apparatus comprising
 a simplified data link processor for receiving the datagram from the Internet, assigning a size value to the datagram, in which the size value is determined as a function of the number of data bytes forming the datagram, and storing the datagram in a buffer selected as a function of a quality of service indicator indicative of a level of priority assigned to the datagram, in which the contents of the selected buffer are then processed at a level commensurate with the assigned priority level, the simplified data link processor including  
 first apparatus for generating a cyclic redundancy code (CRC) over the datagram stored in a buffer currently scheduled for processing and inserting the CRC, quality of service indicator and size value in a header section of a datagram, and for then supplying the resulting datagram to second apparatus,  
 the second apparatus being operative for receiving the data bits forming the resulting datagram and scrambling the bits of the datagram in accordance with a particular scrambling code and supplying the scrambled result to the SONET apparatus, the SONET apparatus including  
 a frame assembler which assembles the scrambled result and associated path overhead information into a payload and  
 a scrambler circuit which then scrambles the payload and associated path overhead information and outputs that scrambled result as a frame of data to the optical path.  
 
     
     
       2. The simplified data link apparatus of  claim 1  wherein the process of scrambling the bits of the datagram in accordance with the particular scrambling code is characterized by a polynomial of 1+x 2 +x 19 +x 21 +x 40 . 
     
     
       3. The simplified data link apparatus of  claim 1  wherein the SONET apparatus further includes a path overhead processor which generates the path overhead information, such that the path overhead information includes a descrambling code derived as a function of the particular scrambling code. 
     
     
       4. The simplified data link apparatus of  claim 1  wherein the SONET apparatus further includes a path overhead processor which generates the path overhead information such that the path overhead information includes a first part of a descrambling code derived as a function of the particular scrambling code and such that the path overhead information generated for a payload of a next succeeding frame includes a second part of the descrambling code. 
     
     
       5. Apparatus for processing a datagram received from Internet facilities and supplying the processed datagram to another transmission facility, said apparatus comprising
 a first scrambler for scrambling the datagram bits starting with a current scrambling code to a form a scrambled datagram and for determining a projected descrambling code that succeeds the current scrambling code by a predetermined number of bits and, and for including the projected descrambling code in the transmission of the scrambled datagram to a receiver, and  
 at the receiver, receiving the scrambled datagram and forming the projected descrambling code into a scrambling code and descrambling the scrambled datagram as a function of the formed scrambling code.  
 
     
     
       6. A method of preventing loss of synchronization between a transmitter of data and a receiver of the data comprising the steps of
 receiving a plurality data bytes forming a data packet,  
 scrambling the bits forming the data bytes in accordance with a predetermined scrambling code,  
 forming the scrambled data bytes into a payload of a frame of data that also includes at least a code to descramble the scrambled data bytes, and  
 scrambling the frame of data in accordance with a predetermined set-reset code to prevent loss of synchronization at the receiver and then transmitting the scrambled frame to the receiver over a transmission path.  
 
     
     
       7. The method of  claim 6  further comprising the steps of
 at the receiver, receiving the scrambled frame of data, and  
 descrambling the scrambled data bytes of the frame payload in accordance with the descrambling code contained in the frame, and outputting the descrambled result to an output.  
 
     
     
       8. The method of  claim 6  further comprising the step of
 receiving the data packet from Internet facilities and processing the received data packet in accordance with a quality-of-service indicator contained in the packet.  
 
     
     
       9. A method of preventing the content of data that is to be transmitted to a receiver of data from disrupting the synchronization between a transmitter of the data and the receiver, said method comprising the steps of
 receiving the data from a source and at least then scrambling the data in accordance with a first scrambling code,  
 forming the scrambled data into a frame of data, and  
 scrambling the frame of data in accordance with a second scrambling code to prevent a disruption of such synchronization and transmitting the scrambled frame to the receiver.  
 
     
     
       10. The method of  claim 9  further comprising the steps of
 at the receiver, receiving the frame of scrambled data and descrambling the received frame of scrambled data in accordance with the second scrambling code, and  
 descrambling the scrambled data in accordance with the first scrambling code.  
 
     
     
       11. The method of  claim 9  further comprising the step of including the first scrambling code in said frame of data. 
     
     
       12. The method of  claim 9  further comprising the steps of
 receiving the data from a predetermined transmission system and processing the received data in accordance with a predetermined quality-of-service indicator contained in the received data.  
 
     
     
       13. Apparatus for processing, in accordance with a simplified data link protocol, a datagram received from an Internet facility and supplying the processed datagram to Synchronous Optical NETwork ( SONET )  apparatus for transmission over an optical path, said datagram being associated with a predetermined quality of service  ( QoS ) , said apparatus comprising:      a simplified data link processor adapted to  (   1   )  receive the datagram from the Internet,  (   2   )  assign a size value to the datagram, in which the size value is determined as a function of the amount of data forming the datagram, and  (   3   )  store the datagram in a buffer selected as a function of a QoS indicator indicative of a level of priority assigned to the datagram, in which the contents of the selected buffer are then processed at a level commensurate with the assigned priority level, the simplified data link processor including:      first apparatus adapted to  (   1   )  generate a cyclic redundancy code  ( CRC )  over the datagram stored in a buffer currently scheduled for processing,  (   2   )  insert the CRC, QoS indicator, and size value in a header section of a datagram, and  (   3   )  supply the resulting datagram to second apparatus; and        the second apparatus adapted to  (   1   )  receive the data forming the resulting datagram,  (   2   )  scramble the datagram in accordance with a particular scrambling code, and  (   3   )  supply the scrambled result to the SONET apparatus, the SONET apparatus including:      an assembler adapted to assemble the scrambled result and associated path overhead information into a payload; and        a scrambler circuit adapted to  (   1   )  scramble the payload and associated path overhead information and  (   2   )  output that scrambled result to the optical path.         
     
     
       14. The simplified data link apparatus of  claim 13 , wherein the process of scrambling the datagram in accordance with the particular scrambling code is characterized by a polynomial of  1 +x 2   +x   19   +x   21   +x   40 . 
     
     
       15. The simplified data link apparatus of  claim 13 , wherein the SONET apparatus further includes a path overhead processor adapted to generate the path overhead information, such that the path overhead information includes a descrambling code derived as a function of the particular scrambling code. 
     
     
       16. The simplified data link apparatus of  claim 13 , wherein the SONET apparatus further includes a path overhead processor adapted to generate the path overhead information such that the path overhead information includes a first part of a descrambling code derived as a function of the particular scrambling code and such that the path overhead information generated for a next succeeding payload includes a second part of the descrambling code. 
     
     
       17. Apparatus for processing a datagram received from Internet facilities and supplying the processed datagram to another transmission facility, said apparatus comprising:
   a first scrambler adapted to  (   1   )  scramble the datagram starting with a current scrambling code to form a scrambled datagram,  (   2   )  determine a projected descrambling code that succeeds the current scrambling code by a predetermined amount of data, and  (   3   )  include the projected descrambling code in the transmission of the scrambled datagram to a receiver adapted to  ( a )  receive the scrambled datagram,  ( b )  form the projected descrambling code into a scrambling code, and  ( c )  descramble the scrambled datagram as a function of the formed scrambling code.     
     
     
       18. A method of preventing loss of synchronization between a transmitter of data and a receiver of the data, the method comprising:
   receiving data forming a data packet;        scrambling the data in accordance with a predetermined scrambling code;        combining the scrambled data with a code to descramble the scrambled data to form combined data;        scrambling the combined data to prevent loss of synchronization at the receiver; and        transmitting the scrambled combined data to the receiver over a transmission path.     
     
     
       19. The method of  claim 18 , further comprising, at the receiver:
   receiving the scrambled combined data;        descrambling the scrambled data in accordance with the descrambling code contained in the combined data; and        outputting the descrambled result to an output.     
     
     
       20. The method of  claim 18 , comprising:
   receiving the data packet from Internet facilities; and        processing the received data packet in accordance with a QoS indicator contained in the packet.     
     
     
       21. The method of preventing the content of data that is to be transmitted to a receiver of data from disrupting the synchronization between a transmitter of the data and the receiver, said method comprising:
   receiving the data from a source;        scrambling the data in accordance with a first scrambling code;        scrambling at least the resulting first scrambled data in accordance with a second scrambling code to prevent a disruption of said synchronization; and        transmitting the resulting second scrambled data to the receiver.     
     
     
       22. The method of  claim 21 , further comprising, at the receiver:
   receiving the second scrambled data;        descrambling the second scrambled data in accordance with the second scrambling code to recover the first scrambled data; and        descrambling the recovered first scrambled data in accordance with the first scrambling code.     
     
     
       23. The method of  claim 21 , comprising:
   combining the first scrambled data and a code to descramble the first scrambled data to form combined data; and        scrambling the combined data with the second scrambling code.     
     
     
       24. The method of  claim 21 , comprising:
   receiving the data from a predetermined transmission system; and        processing the received data in accordance with a predetermined QoS indicator contained in the received data.