COMMUNICATION APPARATUS, COMMUNICATION SYSTEM, ABSENT PACKET DETECTING METHOD AND ABSENT PACKET DETECTING PROGRAM

• US 20090059928A1
• Filed: 08/28/2008
• Published: 03/05/2009
• Est. Priority Date: 08/28/2007
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Higuchi, Junichi, Suzuki, Jun, Yoshikawa, Takashi, Hidaka, Youichi, Enomoto, Nobuyuki, Shimonishi, Hideyuki
• Granted Patent: US 8,233,483 B2
• Time in Patent Office: Days
• US Class Current: 370/394
• CPC Class Codes: H04L 1/1841 Resequencing
• CPC Class Codes: H04L 1/1874 Buffer management
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 2001/0096 Channel splitting in point-to-point links
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 45/28 using route fault recovery

Abstract

Any packet loss is detected very quickly by means of only a series of sequence number in a multi-path environment where a transmitter and a receiver are connected to each other by way of a plurality of networks when no inversion of sequence arises in any of the networks. A communication apparatus includes a plurality of sequence buffers arranged at each network to accumulate packets until a sequence acknowledgement and an absence detecting section adapted to determine the occurrence of an absence of a packet when one or more packets are accumulated in all the sequence buffers. With this arrangement, the absence detecting section of the receiver monitors the packets staying in the sequence guaranteeing buffer arranged in each of the network, paying attention to the characteristic that packets are stored in the sequence buffers of all the networks when a packet loss takes place.

Claims

1. A communication apparatus to be used for an arrangement connecting a transmitter and a receiver to each other by a plurality of networks where no inversion of packet sequence takes place, said apparatus comprising:

a plurality of sequence buffers arranged at the respective networks to accumulate packets until a sequence acknowledgement; and

an absence detecting section adapted to determine the occurrence of an absence of a packet when one or more packets are accumulated in all the sequence buffers.

2. The apparatus according to claim 1, further comprising:

an ACK transmitting section for issuing a retransmission request when an absence of a packet is detected.

3. A communication apparatus to be used for an arrangement connecting a transmitter and a receiver to each other by a plurality of networks where no inversion of packet sequence takes place, said apparatus comprising:

a plurality of sequence buffers arranged at the respective networks to accumulate packets until a sequence acknowledgement;

a takeout control section for checking the sequence numbers added to packets and taking out packets from the sequence buffers, restoring the sequence of flows; and

a storage control section for determining the occurrence of an absence of a packet when any of the sequence buffers overflows.

4. The apparatus according to claim 3, further comprising:

an ACK transmitting section for issuing a retransmission request when an absence of a packet is detected.

5. A communication apparatus to be used for an arrangement connecting a transmitter and a receiver to each other by a plurality of networks where no inversion of packet sequence takes place, said apparatus comprising:

a plurality of sequence buffers arranged at the respective networks to accumulate packets until a sequence acknowledgement;

a takeout control section for checking the sequence numbers added to packets and taking out packets from the sequence buffers, restoring the sequence of flows;

a storage control section for determining the occurrence of an absence of a packet when any of the sequence buffers overflows;

a capacity determining section for determining the capacity of each of the sequence buffers on the basis of the band and the delay time of each of the networks; and

a built-in clock for providing clock time information for computing the delay time.

6. The apparatus according to claim 5, further comprising:

an ACK transmitting section for issuing a retransmission request when an absence of a packet is detected.

7. A communication system to be used for an arrangement connecting a transmitter and a receiver to each other by a plurality of networks where no inversion of packet sequence takes place, said system comprising:

a plurality of sequence buffers arranged at the respective networks to accumulate packets until a sequence acknowledgement; and

an absence detecting section adapted to determine the occurrence of an absence of a packet when one or more packets are accumulated in all the sequence buffers.

8. The system according to claim 7, further comprising:

an ACK transmitting section for issuing a retransmission request when an absence of a packet is detected.

9. The system according to claim 7, further comprising:

a takeout control section for checking the sequence numbers added to packets and taking out packets from the sequence buffers, restoring the sequence of flows; and

a storage control section for determining the occurrence of an absence of a packet when any of the sequence buffers overflows.

10. The system according to claim 7, further comprising:

a takeout control section for checking the sequence numbers added to packets and taking out packets from the sequence buffers, restoring the sequence of flows;

a storage control section for determining the occurrence of an absence of a packet when any of the sequence buffers overflows;

a capacity determining section for determining the capacity of each of the sequence buffers on the basis of the band and the delay time of each of the networks; and

a built-in clock for providing clock time information for computing the delay time;

the transmitter having;

an allocating section for writing the transmission clock time in the packet header so as to allow the capacity determining section to compute the delay time; and

a built-in clock for providing clock time information for computing the delay time.

11. An absent packet detecting method to be used for an arrangement connecting a transmitter and a receiver to each other by a plurality of networks where no inversion of packet sequence takes place:

the receiver being adapted to

accumulate packets in the sequence buffer of each network until sequence acknowledgement; and

determine the occurrence of an absence of a packet when one or more packets are accumulated in the sequence buffers.

12. The method according to claim 11, wherein

the receiver issues a retransmission request when it detects an absence of a packet.

13. The method according to claim 11, wherein the receiver is adapted to:

determine the occurrence of an absence of a packet when any of the sequence buffers overflows.

14. The method according to claim 11, wherein the receiver is adapted to:

determine the occurrence of an absence of a packet when any of the sequence buffers overflows; and

determine the capacity of the sequence buffer from the band and the delay time of each network.

15. A computer program product for causing a computer to execute an absent packet detecting method to be used for an arrangement connecting a transmitter and a receiver to each other by a plurality of networks where no inversion of packet sequence takes place:

the receiver being adapted to

accumulate packets in the sequence buffer of each network until sequence acknowledgement; and

determine the occurrence of an absence of a packet when one or more packets are accumulated in the sequence buffers.

16. The computer program product according to claim 15, wherein

the receiver issues a retransmission request when it detects an absence of a packet.

17. The computer program product according to claim 15, wherein the receiver is adapted to:

determine the occurrence of an absence of a packet when any of the sequence buffers overflows.

18. The computer program product according to claim 15, wherein the receiver is adapted to:

determine the occurrence of an absence of a packet when any of the sequence buffers overflows; and

determine the capacity of the sequence buffer from the band and the delay time of each network.

19. A communication apparatus to be used for an arrangement connecting a transmitter and a receiver to each other by a plurality of networks where no inversion of packet sequence takes place, said apparatus comprising:

a plurality of sequence buffers arranged at respective networks to accumulate packets until a sequence acknowledgement;

a takeout control section for checking the sequence numbers added to packets and taking out packets from the sequence buffers, restoring the sequence of flows;

an overtaking buffer for accumulating the packets delivered by retransmission; and

a retransmission storage control section for allocating the storage destinations to the sequence buffers and the overtaking buffer according to the sequence numbers.

20. The apparatus according to claim 19, further comprising

an ACK transmitting section for issuing a retransmission request when an absence of a packet is detected.

21. A communication system to be used for an arrangement connecting a transmitter and a receiver to each other by a plurality of networks where no inversion of packet sequence takes place,

the receiver having:

a plurality of sequence buffers arranged at respective networks to accumulate packets until a sequence acknowledgement;

a takeout control section for checking the sequence numbers added to packets and taking out packets from the sequence buffers, restoring the sequence of flows;

an overtaking buffer for accumulating the packets delivered by retransmission; and

a retransmission storage control section for allocating the storage destinations to the sequence buffers and the overtaking buffer according to the sequence numbers.

22. The system according to claim 21, wherein

the receiver further having:

an ACK transmitting section for issuing a retransmission request when an absence of a packet is detected.