Packet delivery system

• US 5,440,545 A
• Filed: 08/02/1993
• Issued: 08/08/1995
• Est. Priority Date: 08/02/1993
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Robbins, Karen, Hamilton, R. Lee Jr., Buchholz, Dale R., White, Richard E., Doss, William K.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): BLUM, RUSSELL
• Application Number:
  US08/100,403
• Time in Patent Office: 736 Days
• Field of Search: 370/60, 370/94.1, 370/95.3, 370/58.1, 370/58.2, 370/58.3, 371/32
• US Class Current: 370/426
• CPC Class Codes: H04L 1/1614 using bitmaps
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/1854 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 47/34 ensuring sequence integrity, e.g. using sequence numbers
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A packet switching system (100) having a packet switch (140) employs an acknowledgement scheme in order assure the delivery of all fragments (310) comprising a fragmented data packet (300) to improve overall system throughput during the handling of packets (310) that require reassembly. When packet fragments (310) are lost, corrupted or otherwise unintelligible to a receiving device (92, 94), the acknowledgement scheme permits retransmission of the missing data. In addition, a second acknowledgment signal is scheduled by system processing resources (110) in order to verify the successful delivery of all retransmitted data.

Claims

1. In a packet switching system, a packet switch for acknowledging receipt of a plurality of packet fragments associated with a fragmented data packet, said packet switch comprising:

a transceiver for transmitting acknowledgment signals and receiving said plurality of packet fragments, each packet fragment comprising address, control and data information associated with the fragmented data packet;

said packet switch, coupled to the transceiver and comprising memory logic, for acknowledging, via acknowledgment signal, reception of said packet fragments and determining whether all packet fragments comprising the fragmented data packet have been received;

means, coupled to the memory logic, for enabling a system processor interrupt signal when all packet fragments comprising the fragmented data packet have not been received;

means, coupled to the enabling means, for interrupting a system processing resource via said interrupt signal upon receipt of a retransmitted packet fragment; and

means, coupled to the system processing resource, for scheduling transmission of an acknowledgment signal of the retransmitted packet fragment.

2. In a packet switching system having a packet switch, a method for acknowledging receipt of a plurality of packet fragments associated with a plurality of fragmented data packets, from a source, said method comprising the steps of:

receiving, at said packet switch, a plurality of packet fragments, each packet fragment comprising address, control and data information associated with one of the plurality of fragmented data packets;

said packet switch, acknowledging the reception of each packet fragment and determining whether all packet fragments associated with the received packet fragment and comprising one of the plurality of fragmented data packets have been received;

said packet switch, enabling a system processor interrupt bit when all packet fragments associated with the received packet fragment and comprising one of the plurality of fragmented data packets have not been received;

said source, upon receipt of an acknowledgment, scheduling retransmission of unreceived packet fragments;

said packet switch, interrupting system processing resources via an interrupt signal upon receipt, at said packet switch, of a retransmitted packet fragment;

said system processing resource, scheduling transmission of an acknowledgment signal for delivery to the source to acknowledge receipt of the retransmitted packet fragment.

3. The method of claim 2 further comprising the steps of:

assigning a respective data buffer to each received packet fragment;

storing a data portion of each received packet fragment in the assigned and respective data buffer; and

storing a pointer to each respective data buffer in a control memory structure.

4. The method of claim 2 further comprising the step of copying at least a portion of a received packet fragment'"'"'s control information into memory for identifying a number of TDMA frames required to transmit an acknowledgment for packet fragments comprising the fragmented data packet.

5. In a packet switching system having a packet switch, a method for acknowledging the receipt of packet fragments from a source and associated with a fragmented data packet, said method comprising the steps of:

receiving, at said packet switch, a plurality of packet fragments comprising address, control and data information associated with the fragmented data packet;

copying at least some of the control information into a memory logic structure;

copying at least some of the stored control information into an acknowledgment signal;

transmitting the acknowledgment signal to the source for processing;

determining whether additional acknowledgment signals are required to acknowledge additional packet fragments comprising the fragmented data packet;

determining whether all packet fragments comprising the fragmented data packet have been properly received;

processing the data portion of all packet fragments associated with an original fragmented data packet when all packet fragments comprising the fragmented data packet have been properly received; and

enabling a system processor interrupt bit to permit processing of retransmitted packet fragments when all packet fragments comprising the fragmented data packet were not properly received.