Packet retransmission control system, method and program

• US 20110280240A1
• Filed: 07/19/2011
• Published: 11/17/2011
• Est. Priority Date: 12/14/2009
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Yasuda, Masato, Yamagaki, Nori, Ichino, Kiyohisa
• Granted Patent: US 8,681,618 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 1/1874 Buffer management
• CPC Class Codes: H04L 1/1883 using multiple timers
• 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 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04L 69/32 Architecture of open systems interconnection [OSI] 7-layer type protocol stacks, e.g. the interfaces between the data link level and the physical level
• CPC Class Codes: H04L 69/323 in the physical layer [OSI layer 1]
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04L 69/326 in the transport layer [OSI layer 4] H04L69/16 takes precedence

Abstract

A packet retransmission control system has: a network control block configured to perform packet retransmission control in an upper layer; and a packet retransmission control block configured to perform packet retransmission control with a shorter retransmission timeout than the upper layer in a lower layer that is lower than the upper layer. If the network control block receives a duplicate acknowledge packet being an acknowledge packet notifying a same sequence number for a predetermined number of times, the network control block performs packet retransmission. The packet retransmission control block determines whether or not retransmission of a same packet is performed earlier in the upper layer than in the lower layer. If retransmission of the same packet is performed earlier in the upper layer than in the lower layer, the packet retransmission control block prohibits retransmission of the same packet in the lower layer.

Claims

1. A packet retransmission control system comprising:

a network control block configured to perform packet retransmission control in an upper layer; and

a packet retransmission control block configured to perform packet retransmission control with a shorter retransmission timeout than said upper layer in a lower layer that is lower than said upper layer,

wherein if said network control block receives a duplicate acknowledge packet being an acknowledge packet notifying a same sequence number for a predetermined number of times, said network control block performs packet retransmission,

wherein said packet retransmission control block determines whether or not retransmission of a same packet is performed earlier in said upper layer than in said lower layer, and

wherein if retransmission of said same packet is performed earlier in said upper layer than in said lower layer, said packet retransmission control block prohibits retransmission of said same packet in said lower layer.

2. The packet retransmission control system according to claim 1,

wherein said packet retransmission control block comprises:

a retransmission buffer in which packets for packet retransmission are stored;

a control block; and

an information memory block,

wherein information stored in said information memory block includes a duplicate reception count that is a number of times of receiving said duplicate acknowledge packet by said network control block,

wherein if a packet forwarded from said packet retransmission control block to said network control block is said duplicate acknowledge packet, said control block increments said duplicate reception count,

wherein said control block refers to said duplicate reception count in response to a predetermined trigger, and

wherein if said duplicate reception count is equal to or more than said predetermined number of times, said control block cancels retransmission of said same packet in said lower layer and releases said same packet stored in said retransmission buffer.

3. The packet retransmission control system according to claim 2,

wherein said information stored in said information memory block further includes an acknowledged sequence number that is a sequence number already acknowledged in said upper layer,

wherein if said packet retransmission control block forwards an acknowledge packet in said upper layer to said network control block, said control block compares a latest sequence number being a sequence number acknowledged by said forwarded acknowledge packet with said acknowledged sequence number,

wherein if said latest sequence number is equal to said acknowledged sequence number, said control block determines that said forwarded acknowledge packet is said duplicate acknowledge packet and increments said duplicate reception count, and

wherein if said latest sequence number is newer than said acknowledged sequence number, said control block updates said acknowledged sequence number to said latest sequence number and initializes said duplicate reception count.

4. The packet retransmission control system according to claim 2,

wherein said predetermined trigger is that retransmission timeout regarding said same packet occurs in said lower layer, and

wherein if the retransmission timeout regarding said same packet occurs in said lower layer, said control block refers to said duplicate reception count.

5. The packet retransmission control system according to claim 4,

wherein if said duplicate reception count is less than said predetermined number of times, said control block performs retransmission of said same packet in said lower layer.

6. The packet retransmission control system according to claim 3,

wherein said predetermined trigger is that said packet retransmission control block forwards an acknowledge packet in said upper layer to said network control block, and

wherein said control block refers to said duplicate reception count, after said acknowledge packet in said upper layer is forwarded to said network control block and said duplicate reception count is updated.

7. The packet retransmission control system according to claim 6,

wherein if the retransmission timeout regarding said same packet occurs in said lower layer, said control block performs retransmission of said same packet in said lower layer.

8. A packet retransmission control method comprising:

performing packet retransmission control in an upper layer; and

performing packet retransmission control with a shorter retransmission timeout than said upper layer in a lower layer that is lower than said upper layer,

wherein said performing packet retransmission control in said upper layer comprises;

performing packet retransmission, if a duplicate acknowledge packet being an acknowledge packet notifying a same sequence number is received for a predetermined number of times, and

wherein said performing packet retransmission control in said lower layer comprises;

determining whether or not retransmission of a same packet is performed earlier in said upper layer than in said lower layer; and

prohibiting retransmission of said same packet in said lower layer, if retransmission of said same packet is performed earlier in said upper layer than in said lower layer.

9. A packet retransmission control program recorded on a tangible computer-readable medium that, when executed, causes a computer to perform packet retransmission control processing,

said packet retransmission control processing comprising:

performing packet retransmission control in an upper layer; and

performing packet retransmission control with a shorter retransmission timeout than said upper layer in a lower layer that is lower than said upper layer,

wherein said performing packet retransmission control in said upper layer comprises;

performing packet retransmission, if a duplicate acknowledge packet being an acknowledge packet notifying a same sequence number is received for a predetermined number of times, and

wherein said performing packet retransmission control in said lower layer comprises;

determining whether or not retransmission of a same packet is performed earlier in said upper layer than in said lower layer; and

prohibiting retransmission of said same packet in said lower layer, if retransmission of said same packet is performed earlier in said upper layer than in said lower layer.