Communication control apparatus and communication control method

Abstract

A determining unit determines an allowable rate of data input permitted at a local node. A generating unit generates, when the allowable rate determined by the determining unit is equal to or greater than a target rate of the local node, extended control information including satisfaction information indicating that the target rate is achieved. A transmitting unit transmits the extended control information generated by the generating unit to an upstream node.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram for explaining the essential constitution of a node according to a first embodiment of the present invention;

FIG. 2A is a diagram of an example of an ordinary packet according to the first embodiment;

FIG. 2B is a diagram of an example of an extended packet according to the first embodiment;

FIG. 3 is a diagram of an example of transmission and reception of the extended packet according to the first embodiment;

FIG. 4A is a flowchart explaining the transmission operation of a control frame according to the first embodiment;

FIG. 4B is a diagram continued from FIG. 4A;

FIG. 5A is a diagram of an example of communications between nodes according to the first embodiment;

FIG. 5B is a diagram continued from FIG. 5A;

FIG. 5C is a diagram continued from FIG. 5B;

FIG. 5D is a diagram continued from FIG. 5C;

FIG. 6A is a diagram of an example of communications between nodes according to a second embodiment of the present invention;

FIG. 6B is a diagram continued from FIG. 6A;

FIG. 6C is a diagram continued from FIG. 6B;

FIG. 7A is a diagram of an example of communications between nodes when congestion arises;

FIG. 7B is a diagram continued from FIG. 7A; and

FIG. 7C is a diagram continued from FIG. 7B.

Claims

1. A communication control apparatus in a node that transmits control information including a control rate for controlling an input rate of an upstream node when a congestion occurs during a data transmission from the upstream node to a downstream node in a communication network including a plurality of nodes connected in a form of a ring, the communication control apparatus comprising: a determining unit that determines an allowable rate of data input permitted at a local node;a generating unit that generates, when the allowable rate determined by the determining unit is equal to or greater than a target rate of the local node, extended control information including satisfaction information indicating that the target rate is achieved; anda transmitting unit that transmits the extended control information generated by the generating unit to the upstream node.

2. The communication control apparatus according to claim 1, wherein the determining unit determines a maximum input rate obtained by subtracting a traffic rate of data passing the local node from a transmission capacity rate of the entire communication network as the allowable rate of the local node.

3. The communication control apparatus according to claim 1, further comprising: a control unit that includes a queue capable of storing input data of the local node, and controls an input rate of the input data that passes through the queue based on the allowable rate determined by the determining unit, whereinthe generating unit generates the extended control information when the input data is not stored in the queue.

4. The communication control apparatus according to claim 1, further comprising: a receiving unit that receives either one of extended control information and control information in which an input rate of an arbitrary downstream node is included as the control rate, whereinthe generating unit determines whether to generate the extended control information based on a type of information received by the receiving unit.

5. The communication control apparatus according to claim 4, wherein the generating unit generates the extended control information when the type of information received by the receiving unit is the extended control information and the allowable rate is equal to or greater than the target rate.

6. The communication control apparatus according to claim 5, wherein the generating unit stores either one of a control rate stored in the extended control information received by the receiving unit and an input rate of the local node, whichever is greater, in the extended control information as the control rate.

7. The communication control apparatus according to claim 4, wherein the generating unit generates the control information when the type of information received by the receiving unit is the extended control information and the allowable rate is less than the target rate.

8. The communication control apparatus according to claim 7, wherein the generating unit stores either one of a control rate stored in the extended control information received by the receiving unit and an input rate of the local node, whichever is greater, in the control information as the control rate.

9. The communication control apparatus according to claim 4, wherein the generating unit generates, when the receiving unit receives the control information, the control information including the control rate stored in the received control information, regardless of a magnitude relation of the allowable rate and the target rate.

10. The communication control apparatus according to claim 4, wherein the determining unit determines, when the receiving unit receives the extended control information and the control rate stored in the extended control information is less than the input rate of the local node, a rate obtained by subtracting a sum of a traffic rate of data passing the local node and input rates of all of the downstream nodes from a transmission capacity rate of the entire communication network as the allowable rate of the local node.

11. The communication control apparatus according to claim 4, wherein the determining unit determines, when the receiving unit receives the control information, the control rate stored in the control information as the allowable rate of the local node.

12. The communication control apparatus according to claim 4, wherein the generating unit stores, in the extended control information, difference information relating to a difference between the control rate stored in the extended control information received by the receiving unit and the input rate of the local node.

13. The communication control apparatus according to claim 12, wherein the determining unit calculates a sum of input rates of all of the downstream nodes by use of the difference information, and uses the calculated sum in determining the allowable rate.

14. The communication control apparatus according to claim 12, wherein when the input rate of the local node is stored in the extended control information as the control rate, the generating unit calculates a difference between the input rate of the downstream node and the input rate of the local node as a reference, and updates the difference information with the calculated difference.

15. The communication control apparatus according to claim 4, wherein when the control rate included in either one of the control information the extended control information received by the receiving unit is equal to or greater than a traffic rate of data passing the local node, the generating unit generates the control information without the control rate.

16. A communication control method for a communication control apparatus in a node that transmits control information including a control rate for controlling an input rate of an upstream node when a congestion occurs during a data transmission from the upstream node to a downstream node in a communication network including a plurality of nodes connected in a form of a ring, the communication control method comprising: determining an allowable rate of data input permitted at a local node;generating, when the allowable rate determined at the determining is equal to or greater than a target rate of the local node, extended control information including satisfaction information indicating that the target rate is achieved; andtransmitting the extended control information generated at the generating to the upstream node.