Method for handling reordered data packets

• US 7,382,733 B2
• Filed: 02/12/2004
• Issued: 06/03/2008
• Est. Priority Date: 02/12/2004
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Chirra, Radhika, Banerjee, Dwip N., Venkatsubra, Venkat, Pancholi, Ketan P.
• Primary Examiner(s): Pham; Chi H.
• Assistant Examiner(s): Hoang; Thai D
• Application Number:
  US10/777,723
• Publication Number:
  US 20050180327A1
• Time in Patent Office: 1,573 Days
• Field of Search: 370/389, 370/394, 370/395.52, 370412-418, 370428-429, 370470-474, 370230-236, 709223-224, 709230-236
• US Class Current: 370/236
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/193 at the transport layer, e.g. TCP related
• CPC Class Codes: H04L 47/323 Discarding or blocking control packets, e.g. ACK packets
• CPC Class Codes: H04L 47/34 ensuring sequence integrity, e.g. using sequence numbers
• CPC Class Codes: H04L 47/43 Assembling or disassembling of packets, e.g. segmentation and reassembly [SAR]
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures

Abstract

The present invention provides a method for handling reordered data packets. A method comprises receiving a data packet and determining if the data packet is received out of order. The method further comprises delaying transmission of an acknowledgement indicating that a data packet is missing in response to determining that the data packet is received out of order.

Claims

1. A method, comprising:

receiving a data packet;

determining if the data packet is a next expected data packet;

determining if packet reordering occurred prior to receiving the data packet; and

delaying transmission of an acknowledgement indicating that a data packet is missing in response to determining that the data packet is not the next expected data packet and in response to determining that the packet reordering occurred.

2. The method of claim 1, wherein delaying comprises:

determining that the acknowledgement should be transmitted if the data packet is received out of order; and

waiting a preselected amount of time in response to determining that the acknowledgment should be transmitted.

3. The method of claim 2, further comprising:

determining if the missing data packet is received within the preselected amount of time; and

transmitting the acknowledgment in response to determining that the missing data packet is not received within the preselected amount of time.

4. The method of claim 1, wherein the data packet has an associated sequence number, and wherein determining if the received data packet is the next expected data packet comprises:

determining a sequence number of the next expected data packet; and

determining if the sequence number of the received data packet is not equal to the sequence number of the next expected data packet.

5. The method of claim 1, wherein determining if the packet reordering occurred prior to receiving the data packet comprises:

detecting a missing data packet among one or more data packets that are received prior to receiving the data packet;

transmitting an acknowledgement indicating that the missing data packet has not been received;

receiving the missing data packet, wherein the missing data packet has an associated sequence number;

storing the received sequence number associated with the received data packet that was previously missing;

receiving one or more subsequent data packets having an associated sequence number; and

comparing the stored sequence number to the sequence number associated with the one or more subsequently received data packets to determine if packet reordering occurred.

6. The method of claim 1, wherein receiving the data packet comprises receiving the data packet over a network using at least the Transmission Control Protocol (TCP), and wherein delaying the transmission comprises delaying the transmission of a duplicate ACK.