Access Device and Method for Controlling the Bandwidth

Abstract

An access device for controlling a bandwidth includes a token bucket module and a processing module. The token bucket module is set for each service priority of each logical connection. The processing module is used for receiving a message from a logical connection, taking a token from corresponding token bucket module according to logical connection and priority of the message, comparing byte number of the message with byte number corresponding to the token, forwarding the message if the byte number corresponding to the token is larger than that of the message, and discarding the message otherwise. A method for controlling the bandwidth is also disclosed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram of the implementation principle of the CAR function in the prior art.

FIG. 2 shows a flow chart of the processing of a token generator in the prior art.

FIG. 3 shows a flow chart of the processing of a traffic monitoring module in the prior art.

FIG. 4 shows a schematic diagram for controlling a bandwidth based on a port in combination with the CAR function in the prior art.

FIG. 5 shows a flow chart of the processing of a port based bandwidth limiting policy processing module in the prior art.

FIG. 6 shows a schematic diagram for controlling a bandwidth based on a PVC in combination with the CAR function in the prior art.

FIG. 7 shows a flow chart of the processing of a PVC based bandwidth limiting policy processing module in the prior art.

FIG. 8 shows a schematic diagram for controlling a bandwidth based on a port and a priority using the CAR function in accordance with an embodiment of the present invention.

FIG. 9 shows a flow chart of the processing of a port and priority based bandwidth controlling and processing module in accordance with an embodiment of the present invention.

FIG. 10 shows a schematic diagram for controlling a bandwidth based on a PVC and a priority using the CAR function in accordance with an embodiment of the present invention.

FIG. 11 shows a flow chart of the processing of a PVC and priority based bandwidth controlling and processing module in accordance with an embodiment of the present invention.

EMBODIMENTS OF THE INVENTION

The present invention is hereinafter further described in detail with reference to the accompanying drawings and embodiments.

To implement control of a service bandwidth based on a service priority, a processing module needs to extract priority information of a message first after receiving the message. The priority information can be extracted from an 802.1P area of a Virtual Local Area Network TAG (VLAN TAG) or from a Type of Service (TOS) area in an IP message, and the specific principle for extracting is that the priority information is extracted from the TOS area if the access device operates in a mode of third layer while the priority information is extracted from the 802.1P area if the access device operates in a mode of second layer. The CAR function which is performed based on a port (PVC) and priority in an access device can be activated or inactivated based on user's configuration. Thus, the bandwidth can be controlled based on the service priority no matter the user uses a single PVC or multiple PVCs.

For example, supposing that a user has applied for a bandwidth of 10 M and there are two access devices of user terminal. One is a Set Top Box (STB) and the other is a Personal Computer (PC). The STB establishes a PVC to an access device, thus can access the network as well as acquire the video service; while the PC establishes a PVC to the access device, thus can access the network, perform a voice communication and acquire the video service. The access device performs the CAR based on the service priority. Specifically, the voice communication is regarded as one kind of service and allocated with a bandwidth of, for example, 1 M; video service of the STB and that of the PC are regarded as another kind of service and allocated with a bandwidth of, for example, 6M; network accessing service of the STB and that of the PC are allocated with the remained bandwidth of 3M. With such an allocation of the bandwidth, various services would not take over the bandwidth with each other.

As shown in FIG. 8, the access device includes a token bucket module including a token bucket generator and a token bucket, a port and priority based bandwidth controlling and processing module. A token bucket module is set for each service priority of each port. The port and priority based bandwidth controlling and processing module is connected with each token bucket module and used for receiving messages from each port, taking tokens from corresponding token bucket module according to information of port, priority and frame length of a message, forwarding the message if there are enough tokens, and discarding the message if there are not enough tokens. The 802.1P area and the TOS area are both 3 bits. The 802.1P area and the TOS area can categorize services into services of 8 priorities, that is, services of priority 0 to services of priority 7. Each of the port and priority corresponds to an independent token bucket and thus a bandwidth is controlled based on the port and priority.

As shown in FIG. 9, the processing procedure of the port and priority based bandwidth controlling and processing module is described as follows,

Step 901: reading mode information of an access device and extracting priority information of a message according to the mode information of the access device;

Step 902: reading information of the port and the frame length of the message;

Step 903: determining whether CAR functions based on each port are activated in the access device, performing step 904 if the CAR functions based on each port are activated in the access device, otherwise performing step 905;

Step 904: taking tokens from corresponding token bucket according to the information of the port and the priority;

Step 905; taking a token from a specified token bucket;

Step 906: comparing the byte number of the message with that corresponding to the token, if the byte number corresponding to the token is larger than that of the message, performing step 907, otherwise performing step 908;

Step 907: forwarding the message;

Step 908: discarding the message.

Choosing the priority information is mainly to choose the 802.1P area or the TOS area. The general choosing principle adopted is that the 802.1P area is chosen if the access device operates in a mode of the second layer while the TOS area is chosen if the access device operates in a mode of the third layer. Those discarded messages are passed to a statistical module to be processed. It is determined based on the port whether the port and priority based CAR has been activated, and a port based CAR processing is performed with a fixed choice of the port and priority 0 if the port and priority based CAR has not been activated. The method for choosing the fixed priority is not limited, that is to say, any one of priority 0 to priority 7 can be chosen and then what need to do is to configure corresponding parameters and to set the fixed token bucket module corresponding to a priority.

Though there is another PVC and priority based bandwidth limiting policy in an access though an Asymmetric Digital Subscriber Line (ADSL) or an Asynchronous Transfer Mode (ATM), this policy cannot be applied and only the port and priority based bandwidth control policy can be applied in an IP based access, such as an access though a VDSL2 or an Ethernet, because there is no PVC.

As shown in FIG. 10, the access device includes a PVC and priority based bandwidth controlling and processing module and a token bucket module including a token bucket generator and a token bucket. A token bucket module is set for each service priority of each PVC. The PVC and priority based bandwidth controlling and processing module is connected with each token bucket module and used for receiving messages from each PVC, taking tokens from corresponding token bucket module according to information of PVC, priority and frame length of a message, forwarding the message if there are enough tokens, and discarding the message if there are not enough tokens.

As shown in FIG. 11, the processing procedure of the PVC and priority based bandwidth controlling and processing module is described as follows.

Step 1101: reading mode information of an access device and extracting priority information of a message according to the mode information of the access device;

Step 1102: reading information of the PVC and the frame length of the message;

Step 1103: determining whether CAR functions based on each PVC are activated in the access device, if the CAR functions based on each PVC are activated in the access device, performing step 1104, otherwise performing step 1105;

Step 1104: taking a token from corresponding token bucket according to the information of the PVC and the priority;

Step 1105: taking a token from a specified token bucket;

Step 1106; comparing the byte number of the message with that corresponding to the token, if the byte number corresponding to the token is larger than that of the message, performing step 1107, otherwise performing step 1108;

Step 1107: forwarding the message;

Step 1108: discarding the message.

According to situations of the 802.1P area and the TOS area, priorities are divided into priorities of 8 levels, that is, priority 0 to priority 7, in general. The number of the PVCs is determined based on the number of the PVCs supported by the device and is larger than the number of the ports. Each of the PVC and priority corresponds to an independent token bucket and thus the PVC and priority based bandwidth control can be implemented. Choosing the priority information is mainly to choose the 802.1P area or the TOS area. The general choosing principle is that the 802.1P area is chosen if the access device operates in a mode of the second layer while the TOS area is chosen as the priority area if the access device operates in a mode of the third layer. Those discarded messages are passed to a statistical module to be processed. It is determined according to configurations of the PVC whether the PVC and priority based CAR should be activated, and a PVC based CAR processing is performed with a fixed choice of the PVC and priority 0 if the port and priority based CAR has not been activated. The method for choosing a fixed priority is not limited, that is to say, any one of priority 0 to priority 7 can be chosen and then what need to do is to configure corresponding parameters and to set the fixed token bucket module corresponding to a priority.

Though the present invention has been illustrated and described by referring to preferred embodiments of the present invention, a skilled person in the art should understand that various changes can be made in its form and detail without departing from the spirit or scope of the present invention defined in the appended claims.

Claims

1. An access device, comprising: at least one token bucket module, wherein the each token bucket module corresponds to a service priority of a logical connection;a logical connection and priority based bandwidth controlling and processing module, connected with the each token bucket module, and used for receiving a message from each logical connection, taking a token from the token bucket module corresponding to the logical connection of the message as well as the service priority of the message, comparing byte number of the message with byte number corresponding to the token, if the byte number corresponding to the token is larger than that of the message, forwarding the message; otherwise discarding the message.

2. The access device of claim 1, wherein the token bucket module comprises: a token bucket generator, used for generating the token; anda token bucket, used for holding the token and connecting with the token bucket generator.

3. The access device of claim 1, wherein the logical connection is a port.

4. The access device of claim 1, wherein the logical connection is a Permanent Virtual Connection (PVC).

5. A method for controlling bandwidth comprising: upon receiving a message from a logical connection, extracting information of the logical connection, a service priority and byte number information of the message;taking a token from corresponding token bucket according to the information of the logical connection and the service priority;comparing byte number of the message with byte number corresponding to the token, if the byte number corresponding to the token is larger than the byte number of the message, forwarding the message; otherwise, discarding the message.

6. The method of claim 5, wherein the process of extracting information of the logical connection, a service priority and byte number information of the message comprises: reading mode information of an access device and extracting information of priority of the message according to the mode information of the access device.

7. The method of claim 6, wherein the process of taking a token from corresponding token bucket according to the information of the logical connection and the service priority comprises: determining whether a Committed Access Rate (CAR) function based on each logical connection is activated in the access device, if the CAR function based on each logical connection is activated in the access device, taking the token from the token bucket according to the information of the logical connection and the service priority, otherwise taking the token in a specified token bucket.

8. The method of claim 5, wherein the logical connection is a port.

9. The method of claim 5, wherein the logical connection is a Permanent Virtual Connection (PVC).