Limited automatic repeat request protocol for frame-based communication channels

• US 20070263631A1
• Filed: 05/08/2007
• Published: 11/15/2007
• Est. Priority Date: 05/21/1999
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Tracy Mallory
• Inventors: Mallory, Tracy
• Granted Patent: US 8,503,451 B2
• Time in Patent Office: Days
• US Class Current: 370/394
• CPC Class Codes: H04L 1/1635 Cumulative acknowledgement, i.e. the acknowledgement message applying to all previous messages
• CPC Class Codes: H04L 1/1664 the supervisory signal being transmitted together with payload signals; piggybacking
• CPC Class Codes: H04L 1/1685 the supervisory signal being transmitted in response to a specific request, e.g. to a polling signal
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/1832 Details of sliding window management
• CPC Class Codes: H04L 1/1838 for semi-reliable protocols, e.g. for less sensitive applications such as streaming video buffer level management for video bitstream receiver H04N21/44004
• CPC Class Codes: H04L 1/1841 Resequencing
• CPC Class Codes: H04L 1/1848 Time-out mechanisms
• CPC Class Codes: H04L 1/1858 Transmission or retransmission of more than one copy of acknowledgement message
• CPC Class Codes: H04L 1/1877 for semi-reliable protocols, e.g. for less sensitive applications like streaming video buffer level management for video bitstream control arrangements H04N21/44004
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 2001/125 Arrangements for preventing errors in the return channel
• 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

Abstract

In a frame-switched network, a sender sends frames to a receiver over a possibly unreliable channel. Sent frames include frame identifiers that can be used for a limited automatic repeat request. Upon receipt of a frame, the receiver determines, from the frame identifier, if frames prior to the received frame were lost in transit. If the receiver determines that it missed a prior frame, the receiver sends the sender a negative acknowledgment (nack) for the missed prior frame or frames. Otherwise, if the receiver receives a frame correctly, it does not acknowledge the frame. The frame identifiers can be a set of sequential integers with frames transmitted in sequential frame order. In some embodiments, when a receiver receives a frame out of order, the receiver buffers the out of order frame in a receiver buffer for a receive buffer period until preceding frames are received or a receive buffer period expires. The sender can send a reminder frame to the receiver to allow the receiver to detect a missed prior frame missing from an end of a frame sequence. The channel between the sender and the receiver can be a bidirectional channel over a telephone wire, a cable, a radio frequency link or a power wire. Multiple logical channels might be set up between a given sender-receiver pair, to allow for traffic of varying priorities.

Claims

1. A method comprising:

receiving a first frame at a receive station, the first frame having a first sequence number;

passing the first frame up to a higher layer at the receive station for processing;

receiving a subsequent frame at the receive station, the subsequent frame having a sequence number that is out of sequence as compared to the sequence number of the first received frame;

determining a missing frame based on the sequence number for the subsequent frame that is out of sequence; and

passing the subsequent frame up to the higher layer at the receive station for processing after a period of time has elapsed since the missing frame was determined, even if the missing frame has not been received at the receive station.

2. An apparatus, the apparatus configured to:

receive a first frame at a receive station, the first frame having a first sequence number;

pass the first frame up to a higher layer at the receive station for processing;

receive a subsequent frame at the receive station, the subsequent frame having a sequence number that is out of sequence as compared to the sequence number of the first received frame;

determine a missing frame based on the sequence number for the subsequent frame that is out of sequence; and

pass the subsequent frame up to the higher layer at the receive station for processing after a period of time has elapsed since the missing frame was determined, even if the missing frame has not been received at the receive station.

3. An apparatus including a processing circuit, the apparatus configured to:

generate a frame at a send station in a network;

send the frame from the send station to a receive station;

determine a period of inactivity that exceeds a threshold during which no further frames are sent from the send station to the receive station; and

send, in response to the determining, a reminder frame to the receive station identifying a last frame transmitted from the send station to the receive station.

4. The apparatus of claim 3 wherein the apparatus being configured to generate comprises the apparatus being configured to generate a frame at a send station in a network, the generated frame including a sequence number to identify the frame.

5. The apparatus of claim 3 wherein the apparatus being configured to generate comprises the apparatus being configured to generate a frame at a send station in a network, the generated frame including a sequence number to identify the frame, sequence numbers being assigned to frames per destination or receive station and per priority level.

6. The apparatus of claim 3 wherein the apparatus is further configured to:

receive at the send station a negative acknowledgement (NACK) from the receive station indicating that one or more transmitted frames from the send station were not received by the received station; and

re-send, in response to receiving the NACK, the one or more frames from the send station to the receive station.

7. The apparatus of claim 3 wherein the apparatus is further configured to:

reset a reminder timer for the after each time a frame is sent from the send station to the receive station; and

wherein the apparatus being configured to determine comprises the apparatus being configured to determine a period of inactivity based on an expiration of the reminder timer.

8. The method of claim 3 wherein the apparatus is further configured to:

store a copy of the frame in a transmit buffer at the send station; and

discard the copy of the frame if a resource constraint at the send station is met.

9. The apparatus of claim 3 wherein the apparatus being configured to determine a period of inactivity comprises the apparatus being configured to determine a period of inactivity that exceeds a threshold during which no further frames are sent from a send station to a MAC address of the receive station.