APPARATUS AND METHOD FOR OPTIMIZING COMMUNICATIONS AT AN INTERMITTENT COMMUNICATION LINK

• US 20140064095A1
• Filed: 09/06/2012
• Published: 03/06/2014
• Est. Priority Date: 09/06/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Li, Li, Juang, Ben-Heng, Mathias, Arun G.
• Granted Patent: US 10,187,315 B2
• Time in Patent Office: Days
• US Class Current: 370/236
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04W 80/06 Transport layer protocols, e.g. TCP [Transport Control Protocol] over wireless transmission control protocol/Internet protocol [TCP/IP] or user datagram protocol [UDP] H04L69/16

Abstract

Apparatus and methods for optimizing communications at a communication processor that exchanges communications across a communication link on behalf of an application processor or other local endstation of the communications, wherein the communication link is intermittently inoperative. The application processor is a source or destination of communication packets that traverse the link, while the communication processor transmits and receives the packets for the application processor. Packets are queued at the communication processor for transmit while the link is temporarily inoperative. A filter operates to select obsolete packets for discard. Obsolete packets may include packets for which a subsequent FIN packet (or other termination notice) is received, and may also include packets that have associated deadlines that expire or that will expire before they can be delivered. Obsolete packets may further include packets that have been retransmitted while the link is inoperative.

Claims

1. A method of optimizing communications at an intermittent communication link, the method comprising:

queuing multiple packets for transmission across a communication link that is temporarily disabled, at a transmitter that is not an endstation of any communication connection to which the multiple packets belong;

receiving a notification of termination of a first communication connection that includes at least one packet of the multiple packets;

selecting the at least one packet for discard; and

after the communication link is enabled, transmitting the notification of termination of the first communication connection across the communication link, but not the at least one packet.

2. The method of claim 1, further comprising:

before the communication link is enabled, receiving a set of packets, each packet having an associated deadline;

selecting for discard a subset of the set of packets for which the associated deadlines have expired; and

forwarding all packets in the set of packets except the selected subset.

3. The method of claim 2, further comprising:

selecting for discard a second subset of the set of packets for which the associated deadlines are predicted to expire before they are delivered to corresponding destinations.

4. The method of claim 1, wherein the transmitter is not an endstation of a given communication connection if it is not the source or destination of the given communication connection.

5. The method of claim 1, wherein the notification of termination of the first communication connection is received from an endstation local to the transmitter, before the communication link is enabled.

6. The method of claim 1, wherein the notification of termination of the first communication connection is received across the communication link after the communication link is enabled.

7. The method of claim 1, wherein the notification of termination of the first communication connection is a FIN packet.

8. The method of claim 7, wherein selecting a packet for discard comprises:

matching addresses and ports of the source and destination of the notification of termination with addresses and ports of the source and destination of the at least one packet.

9. The method of claim 1, wherein selecting a packet for discard comprises marking the packet for discard.

10. The method of claim 1, wherein selecting a packet for discard comprises discarding the packet.

11. A computer-readable medium storing instructions that, when executed by a computer, cause the computer to perform a method of optimizing communications at an intermittent communication link, the method comprising:

queuing multiple packets for transmission across a communication link that is temporarily disabled, at a transmitter that is not an endstation of any communication connection to which the multiple packets belong;

receiving a notification of termination of a first communication connection that includes at least one packet of the multiple packets;

selecting the at least one packet for discard; and

after the communication link is enabled, transmitting the notification of termination of the first communication connection across the communication link, but not the at least one packet.

12. A method of optimizing communications at an intermittent communication link, the method comprising:

queuing multiple packets for transmission across a communication link that is temporarily disabled, at a transmitter that is not the source or the destination of any communication connection to which the multiple packets belong;

when the communication link is enabled, for each of the multiple packets that has an associated deadline;

comparing the associated deadline with a current duration of the packet; and

selecting the packet for discard if the current duration exceeds the associated deadline; and

after the communication link is enabled, transmitting only packets in the multiple packets that were not selected for discard.

13. The method of claim 12, further comprising, prior to the communication link being enabled:

receiving a termination packet for a first communication connection; and

selecting for discard one or more of the multiple packets that belong to the first communication connection.

14. The method of claim 12, further comprising, after the communication link is enabled:

receiving across the communication link a termination packet for a first communication connection; and

selecting for discard one or more of the multiple packets that belong to the first communication connection.

15. Apparatus for optimizing communications across an intermittent communication link, the apparatus comprising:

an application processor terminating one or more communication connections that traverse the communication link;

a baseband processor configured to transmit and receive communications across the communication link, wherein the communication link is temporarily inoperative;

logic configured to identify obsolete communications at the baseband processor; and

a filter configured to select for discard communications identified by the logic.

16. The apparatus of claim 15, wherein obsolete communications include packets belonging to a communication connection, among the one or more communication connections, for which a subsequent notification of termination of the connection is received.

17. The apparatus of claim 15, wherein obsolete communications include packets belonging to one of the one or more communication connections and having associated deadlines that expire before the communication link is operative.

18. The apparatus of claim 15, wherein obsolete communications include packets that have been retransmitted by the application processor while the communication link is temporarily inoperative.

19. The apparatus of claim 15, wherein the obsolete communications are identified while the communication link is temporarily inoperative.

20. The apparatus of claim 15, wherein the baseband processor is not the source or destination of any of the one or more communication connections.