The Data Transfer Protocol
Abhay K. Bhushan, Bob Braden, W. Crowther, E. Harslem, J. F. Heafner, A. McKenize, J.T. Melvin, B. Sundberg, D. Watson, Joseph White · 1971
This paper is a revision of RFC 171, NIC 6793.The changes to RFC 171 are given below.The protocol is then restated for your convenience. CHANGES TO RFC 1711) The sequence number field is changed to 16 bits in the error (Type B5) transactions, thus resolving the ambiguity in the previous specification.In addition, the information separators (Type B4) transactions shall also contain a 16-bit sequence number field.2) The modes available (Type B3) transactions shall define only the modes available for receive, instead of both receive and send.In simplex connections modes available transactions should not be sent as they are meaningless.In full-duplex connections, the modes available transactions are still required.3) The code assignments for "End Code" in information separators and for "function" in abort transactions have been changed to reflect a numerical order rather than "bit-coding".4) Minor editorial changes.