公开(公告)号：DE3876776D1

公开(公告)日：1993-01-28

申请号：DE3876776

申请日：1988-01-22

Applicant: IBM

Inventor： BUX WERNER KLAUS ,  KLEINOEDER WOLFGANG B ,  KERMANI PARVIZ

IPC: H04L29/08 ,  H04L1/00 ,  H04L1/16 ,  H04L1/18 ,  H04L29/06 ,  H04L12/00

Abstract: In the Checkpoint Mode Protocol (CPM), checkpoint frames are transmitted at regular intervals for acknowledging received information frames and individually requesting retransmission of missing information frames. The disclosed invention reduces the flow of checkpoint frames in situations where their information is not required. This is achieved by either sending a Stop Checkpointing frame from sender to receiver in particular situations, or by inserting, in the case of duplex transmission (i.e. both stations are sending and receiving), Request-Reply bits into normal checkpoint frames for suppressing the flow of checkpoint frames when they are not necessary. In each case, provisions are made to resume the transmission of checkpoint frames as soon as they are required again.

公开(公告)号：DE3579466D1

公开(公告)日：1990-10-04

申请号：DE3579466

申请日：1985-12-23

Applicant: IBM

Inventor： MUELLER JOHANN RUDOLF ,  ZAFIROPULO PITRO ALOIS ,  CLOSS FELIX HUGO ,  BUX WERNER KLAUS ,  VAN AS HARMEN ROELOF

IPC: H04Q11/04 ,  H04L12/433 ,  H04L12/46 ,  H04L12/64 ,  H04L12/28

Abstract: In a local area communication system comprising token rings (11) with synchronous bandwidth managers SBM (15) for issuing priority tokens for quasi-synchronous frames at regular intervals, the rings are interconnected by a time division muliplex PBX unit (31, 33) via their SBM units. Buffers are provided in each SBM for synchron­ous information blocks transferred from and to the ring, and the TDM control (31) can independently access these buffers for TDM switching of the individual bytes of said information blocks. Besides this PBK interconnection for synchronous information or voice, the rings are also interconnected by a backbone bus or ring for transfer of asynchronous data between rings. A special slot re­arrangement procedure is provided to improve the filling of time slots in the quasi-synchronous frames that are no longer used after release of a connection, to allow for addapting the frame length (number of issued slots) to the number of existing connections.

公开(公告)号：DE3876776T2

公开(公告)日：1993-07-01

申请号：DE3876776

申请日：1988-01-22

Applicant: IBM

Inventor： BUX WERNER KLAUS ,  KLEINOEDER WOLFGANG B ,  KERMANI PARVIZ

IPC: H04L29/08 ,  H04L1/00 ,  H04L1/16 ,  H04L1/18 ,  H04L29/06 ,  H04L12/00

Abstract: In the Checkpoint Mode Protocol (CPM), checkpoint frames are transmitted at regular intervals for acknowledging received information frames and individually requesting retransmission of missing information frames. The disclosed invention reduces the flow of checkpoint frames in situations where their information is not required. This is achieved by either sending a Stop Checkpointing frame from sender to receiver in particular situations, or by inserting, in the case of duplex transmission (i.e. both stations are sending and receiving), Request-Reply bits into normal checkpoint frames for suppressing the flow of checkpoint frames when they are not necessary. In each case, provisions are made to resume the transmission of checkpoint frames as soon as they are required again.