PACKET RELAY APPARATUS AND CONGESTION CONTROL METHOD

• US 20110128853A1
• Filed: 11/30/2010
• Published: 06/02/2011
• Est. Priority Date: 12/01/2009
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: NISHIMURA, Kazuto
• Granted Patent: US 8,780,719 B2
• Time in Patent Office: Days
• US Class Current: 370/235
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/22 Traffic shaping

Abstract

A packet relay apparatus relaying a packet exchanged between communication apparatuses with a connection established is provided. The packet relay apparatus includes a buffer for storing a packet selected from among arrival packets so that a transfer of the selected packet is to be suspended, and a congestion controller for monitoring, after the storage of the packet on the buffer, a packet passing through the packet relay apparatus, and causing the packet, stored on the buffer, to be transmitted at a timing responsive to a passage status of a packet having the same connection as the connection of the packet stored on the buffer.

Claims

1. A packet relay apparatus relaying a packet exchanged between communication apparatuses with a connection established, the packet relay apparatus comprising:

a buffer to store a packet selected from among arrival packets so that a transfer of the selected packet is to be suspended; and

a congestion controller to monitor, after the storage of the packet on the buffer, a packet passing through the packet relay apparatus, and causing the packet, stored on the buffer, to be transmitted at a timing responsive to a passage status of a packet having a same connection as the connection of the packet stored on the buffer.

2. The packet relay apparatus according to claim 1, wherein the congestion controller determines the timing based on a number of packets having the same connection passing through the packet relay apparatus.

3. The packet relay apparatus according to claim 2, wherein the congestion controller determines the timing based on the number of packets having the same connection and a time elapse from a previous detection of a packet of the same connection.

4. The packet relay apparatus according to claim 3, wherein the congestion controller estimates the number of response packets a communication apparatus operating as a destination of the packet stored on the buffer has transmitted to a communication apparatus operating as a source, based on the number of packets of the same connection and the time elapse, and determines the timing based on the estimated number of response packets.

5. The packet relay apparatus according to claim 1, wherein the congestion controller determines the timing based on a time elapse from the storage of the packet on the buffer.

6. The packet relay apparatus according to claim 1, wherein the congestion controller corrects a parameter for use in the determination of the timing based on the passage status if a retransmission of the packet stored on the buffer is detected.

7. The packet relay apparatus according to claim 6, wherein the parameter includes at least one of a threshold value on the number of packets having the same connection having passed through the packet relay apparatus and a threshold value on the time elapse from a previous detection of the packet having the same connection.

8. The packet relay apparatus according to claim 6, wherein the congestion controller corrects the parameter for use in the determination of the timing based on the time elapse from the storage of the packet on the buffer.

9. The packet relay apparatus according to claim 1, further comprising another buffer to temporarily store a packet waiting for transmission,

wherein the congestion controller determines a maximum number of connections of packets that are to be stored on the buffer, based on a number of packets retained on the other buffer.

10. A congestion control method in a packet relay apparatus relaying a packet exchanged between communication apparatuses with a connection established, the congestion control method comprising:

storing, on a buffer, a packet selected from among arrival packets so that a transfer of the selected packet is to be suspended; and

monitoring, after the storage of the packet on the buffer, a packet passing through the packet relay apparatus, and causing the packet, stored on the buffer, to be transmitted at a timing responsive to a passage status of a packet having a same connection as the connection of the packet stored on the buffer.

11. The congestion control method according to claim 10, further comprising:

determining the timing based on a number of packets having the same connection passing through the packet relay apparatus.

12. The congestion control method according to claim 11, wherein

the determining includes determining the timing based on the number of packets having the same connection and a time elapse from a previous detection of a packet of the same connection.

13. The congestion control method according to claim 12, further comprising:

estimating the number of response packets a communication apparatus operating as a destination of the packet stored on the buffer has transmitted to a communication apparatus operating as a source, based on the number of packets of the same connection and the time elapse, and determines the timing based on the estimated number of response packets.

14. The congestion control method according to claim 10, further comprising:

determining the timing based on a time elapse from the storage of the packet on the buffer.

15. The congestion control method according to claim 10, further comprising:

correcting a parameter for use in the determination of the timing based on the passage status if a retransmission of the packet stored on the buffer is detected.

16. The congestion control method according to claim 15, wherein the parameter includes at least one of a threshold value on the number of packets having the same connection having passed through the packet relay apparatus and a threshold value on the time elapse from a previous detection of the packet having the same connection.

17. The congestion control method according to claim 15, wherein

the correcting includes correcting the parameter for use in the determination of the timing based on the time elapse from the storage of the packet on the buffer.

18. The congestion control method according to claim 10, further comprising:

storing, on another buffer, a packet waiting for transmission, and wherein

the determining includes determining a maximum number of connections of packets that are to be stored on the buffer, based on a number of packets retained on the other buffer.