System and process for controlling the flow of either data packets or channel signals in an asynchronous time multiplexer

• US 4,993,024 A
• Filed: 04/18/1988
• Issued: 02/12/1991
• Est. Priority Date: 05/26/1987
• Status: Expired due to Term

• Current Assignee: L'Etat Francais Represente PAR Le Ministre Des PTT Centre National D'Etudes Des Telecommunications 5cnet
• Original Assignee: L'Etat Francais Represente PAR Le Ministre Des PTT Centre National D'Etudes Des Telecommunications 5cnet
• Inventors: Francois, Joel, Quinquis, Jean-Paul, Servel, Michel
• Primary Examiner(s): Safourek, Benedict V.
• Assistant Examiner(s): Jung, Min
• Application Number:
  US07/182,912
• Time in Patent Office: 1,030 Days
• Field of Search: 370/94, 370/60, 370/84, 370/13, 370/108, 375/109, 375/118
• US Class Current: 370/230
• CPC Class Codes: H04L 12/5602 Bandwidth control in ATM Networks, e.g. leaky bucket
• CPC Class Codes: H04L 2012/5614 User Network Interface
• CPC Class Codes: H04L 2012/563 Signalling, e.g. protocols, reference model
• CPC Class Codes: H04L 2012/5636 Monitoring or policing, e.g. compliance with allocated rate, corrective actions
• CPC Class Codes: H04L 2012/5637 Leaky Buckets
• CPC Class Codes: H04L 2012/5647 Cell loss

Abstract

A system and process for controlling the flow of packets carried by asynchronous time multiplex (EPACi) channels. The packets from one communication link are identified by their label and the identity of the multiplex channels which carries them. The process is comprised of allocating for each communication a predetermined clock rate and a predetermined threshold value, measuring the difference between the number of packets entering belonging to the communication and the number of pulses generated by the clock, lower bounding this difference, and, if the difference reaches a predetermined threshold, triggering a signal (DEP) which causes the detection of packets belonging to the communication in question as long as the difference is not less than the predetermined threshold. The signal (DEP) is used by the control means of a switch (XPAC) which transmits to the source of the communication in question a message requesting it to reduce its rate, when this is possible, and, in any event, a message warning it of a loss of packets.

Claims

1. A process for controlling the flow of data packets carried by asynchronous time multiplex channels of a system comprising an up-down counter means having a down counting input which receives pulses of the communication at a maximum peak rate that is allocated to the pertinent communication and having another counting input which receives a pulse upon the transmission of each data packet belonging to the pertinent communication, each of the data packets from any one communication carried by said channel being identified by its label and by an identity of the multiplex channel which carries it, said process comprising the steps of:

A. allocating to each communication a predetermined clock frequency and a predetermined threshold value representing a particular difference between a number of entering data packets and a number of clock pulses generated at said predetermined clock frequency, and operating said up-down counter means in response to said received data packets;

B. determining an actual difference between a number of entering data packets belonging to the communication and a number of pulses generated at said predetermined clock frequency;

C. setting a boundary for this difference determined in step B; and

D. if said difference reaches the said predetermined threshold, triggering a signalling process which starts a deletion of data packets belonging to the pertinent communication until said difference returns to a value which does not reach said predetermined threshold, a maximum count output of the up-down counter means generating a signalling requesting a reduction in rate of said received pulses of said communication.

2. The process in accordance with claim 1, and the further steps of:

sending a signal to a source transmitting the pertinent communication in order to request it to reduce its rate of transmission, and for transmitting a message warning said source that there may be a loss of data packets during transmission.

3. The process in accordance with claim 1, and the further steps of:

sending a signal to a source transmitting the pertinent communication in order to request it to reduce the clock frequency rate of transmission, and for transmitting a message warning said source that there may be a loss of data packets during transmission at said reduced rate.

4. The process in accordance with claim 1 and the added step of occasionally receiving empty packets, identifying empty packets upon the arrival thereof responsive to an empty packet label carried by said packets in order to inhibit an addressing of the memory during reading.

5. The process in accordance with claim 4, and the added step of triggering an access authorization to the memory during a writing period for the control unit in response to said identifying an empty packet.