CN100505608C - An adaptive congestion control method and system suitable for satellite networks - Google Patents

Abstract

The method includes steps: a transmitting device (TD) sends message to receiving device (RD); TD receives feedback information (info); if it is congestion info, then, reducing quantity of sending out message; if it is link error info, then, retransmitting lost message; if it is message acceptance acknowledgement (ACK) info, then, continuing sending message; if no feedback info is received after a prearranged period of time, then, restarting sending message. The system includes following parts: TD in use for sending message and receiving feedback info; middle gateway node in use for feeding back congestion info to TD, and discarding a certain amount of message to decelerate congestion condition; RD in use for receiving message from TD through middle gateway node, feeding back link error info through repeated ACK, and ACK info of receiving message to TD. The invention raises throughput and fairness of satellite network, and reduces transmission delay.

Description

An adaptive congestion control method and system suitable for satellite networks

technical field

The invention relates to an adaptive congestion control method and system suitable for satellite networks, in particular to an adaptive congestion control method and system applied to satellite networks.

Background technique

With the advent of information globalization and the combined development of multimedia technology and telecommunication technology, many new application requirements have emerged, such as multimedia conferencing, virtual reality and computer visualization. They all require high-speed processing and high-speed transmission as technical support. Because satellite network communication has unique functions such as space spanning, long-distance communication and broadcasting, and can provide users with various communication methods from voice to data, from low speed to high speed, from single communication to multimedia communication, and from fixed to mobile, etc. Satellite network communication is playing an increasingly important role in the field of communication systems. Correspondingly, network management has become an essential part of the satellite communication network.

In order to provide data transmission services more effectively and reduce interface conversion with other network protocols, the application of Transmission Control Protocol (TCP) in satellite communication networks has attracted attention. The core of TCP is the congestion control mechanism. Network congestion is caused by the traffic overload of the router, that is, when the data traffic exceeds the buffer processing capacity of the router, the router will discard the data segment. After network congestion occurs, in addition to retransmitting the lost data segment, TCP also reduces its transmission rate to reduce the data flow in the network, so that the router has enough time to process and forward the data segment. Then TCP gradually increases the transmission rate to detect the capacity of the network to avoid the recurrence of congestion.

TCP designed for wired networks performs well in terrestrial wired networks, but its performance is severely affected in satellite networks. Because the bit error rate of the terrestrial wired network is very low, packet loss is caused by link congestion. However, the bit error rate of the satellite network is high, and message loss may be caused by link bit errors. Therefore, the TCP congestion control designed for the cable network causes the problems of low throughput and lack of fairness in the satellite network, and cannot meet the needs of the satellite network.

Contents of the invention

The purpose of the present invention is to provide a kind of self-adaptive congestion control method and system suitable for the satellite network, thereby improving the satellite network throughput and fairness.

In order to achieve the above object, the present invention provides a method for adaptive congestion control suitable for satellite networks, comprising the following steps:

The sending device sends messages to the receiving device in an exponential growth manner;

The sending device receives the feedback information, if the feedback information is congestion information, the sending device reduces the amount of packets sent to the receiving device; if the feedback information is link error information, the sending device keeps the original sending Retransmit the lost message to the receiving device at the same rate; if the feedback information is message reception confirmation information, the sending device continues to send messages to the receiving device;

If the sending device does not receive the feedback information after a predetermined period of time, the sending device will reduce the message sending amount to 1 and restart sending messages to the receiving device in an exponentially increasing manner.

Using the above method, the cause of packet loss is identified through congestion information and link error information, and the packet loss caused by link congestion and link error is processed separately, and the complete recovery algorithm is used, thereby greatly improving throughput and Fairness reduces transmission delay.

Based on the above adaptive congestion control method suitable for satellite networks, the present invention also provides an adaptive congestion control system suitable for satellite networks, including:

The sending device is used to send messages and receive feedback information, specifically including a message sending module and a feedback information receiving module; the message sending module is used to send messages; the feedback information receiving module is used to receive the congestion information, the feedback information receiving module The link error code information and the message receiving confirmation information; the feedback information receiving module is connected with the message sending module;

The intermediate gateway node is used to feed back the congestion information to the sending device and discard a certain amount of packets at the same time to alleviate the congestion situation;

The receiving device is configured to receive the message sent by the sending device through the intermediate gateway node, and feed back link error information and message reception confirmation information to the sending device through repeated confirmation.

Using the above system, the network can identify the cause of message loss through the intermediate gateway node feeding back the congestion information and the receiving device feeding back the link error information, and realize the complete recovery algorithm through the message sending volume control module, which can improve the network throughput and fairness.

Description of drawings

Fig. 1 is a flow chart of Embodiment 1 of an adaptive congestion control method suitable for a satellite network according to the present invention;

FIG. 2 is a partial flowchart of Embodiment 2 of an adaptive congestion control method suitable for a satellite network according to the present invention;

3 is a structural diagram of Embodiment 1 of an adaptive congestion control system suitable for a satellite network according to the present invention;

FIG. 4 is a structural diagram of Embodiment 2 of an adaptive congestion control system suitable for a satellite network according to the present invention.

Detailed ways

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

The present invention provides a kind of self-adaptive congestion control method suitable for satellite network, comprises the following steps:

The sending device sends a message to the receiving device;

The sending device receives the feedback information, if the feedback information is congestion information, the sending device reduces the amount of packets sent to the receiving device; if the feedback information is link error information, the sending device sends a message to the receiving device The device retransmits the lost message; if the feedback information is message reception confirmation information, the sending device continues to send the message to the receiving device;

If the sending device does not receive the feedback information after a predetermined period of time, the sending device restarts sending messages to the receiving device.

Fig. 1 is the flow chart of this method embodiment 1, specifically comprises the following steps:

The sending device sends a message to the receiving device through the intermediate gateway node, and the network enters the slow start phase. Slow start is a standard algorithm in the TCP protocol. In slow start, the amount of packets sent changes as 1, 2, 4, 8..., which is an exponential growth method;

When the amount of packets sent reaches the predetermined threshold, in order to prevent link congestion, the amount of packets sent must be reduced, and the network enters the congestion avoidance stage, and the amount of packets sent is added in an additive manner, that is, the amount of packets sent increases by 1 each time. increase.

The sending device judges according to the content of the received feedback information;

If the feedback information is the congestion information fed back by the intermediate gateway node, that is, Dynamic Random Early Detection—Explicit Congestion Notification (DRED-ECN) feedback, the sending device reduces the number of packets sent to the receiving device. The amount of sent messages can be reduced to half of the original amount of sent messages and sent to the receiving device in an additive growth manner, and the amount of sent messages can also be reduced to other suitable satellite network transmissions;

If the feedback information is link error information fed back by the receiving device, that is, repeated confirmation, the sending device retransmits the lost message to the receiving device;

If the feedback information is message reception confirmation information, the sending device continues to send messages to the receiving device.

If the sending device does not receive congestion information, link error information or packet reception confirmation information after a predetermined period of time, it means that the network status is unknown, then according to the most conservative method, re-enter the slow start stage, that is, the sending device Reduce the number of packets sent to 1 and send packets to the receiving device in an exponential manner.

This embodiment introduces DRED-ECN feedback and repeated confirmation in the satellite network. If the sending device receives the DRED-ECN feedback, it means that the link in the network is congested. The link error information is composed of multiple repeated message reception confirmation information. After receiving a message, the receiving end must send the corresponding message receiving confirmation information ACK. For example, the receiving end sends the corresponding message after receiving the message numbered 87. The packet receipt confirmation information ACK. If the message numbered 88 is not received after a period of time t, the receiving end will send the acknowledgment message ACK of 87 again to indicate that it is waiting for the message 88, and then send the message acknowledgment of message 87 every time it waits for a period of time. Information ACK, the sender receives such multiple repeated message receipt confirmation information ACK is called duplicate acknowledgment. In this embodiment, the cause of message loss is identified through congestion information and link bit error information, and the message loss caused by link congestion and link bit error is processed separately, thereby greatly improving throughput and fairness, and reducing transmission time. delay.

FIG. 2 is a partial flowchart of Embodiment 2 of an adaptive congestion control method suitable for a satellite network according to the present invention. In Embodiment 2, if the feedback information is link error information fed back by the receiving device, that is, repeated confirmation, it is specifically: retransmit the lost message to the receiving device according to the original message sending rate, that is, fast retransmit the lost message message; after the lost message is retransmitted, the sending device sends messages to the receiving device in an additive growth manner at the original message sending rate.

In Embodiment 2, the message loss caused by link congestion and link bit error is also handled separately, and since the cause of message loss has been distinguished according to the link bit error information and congestion information, when the system knows that If most of the packets are lost due to link errors, instead of reducing the amount of packets sent according to the traditional method, according to the complete recovery algorithm, the amount of packets sent remains unchanged and enters the congestion avoidance stage, thereby further improving throughput. amount and reduce the transmission delay.

Based on the above adaptive congestion control method suitable for satellite network, the present invention also provides an adaptive congestion control system suitable for satellite network. 4 is a structural diagram of Embodiment 1 of an adaptive congestion control system suitable for a satellite network according to the present invention. The system includes: a sending device 1, further specifically including a message sending module 11, a feedback information receiving module 12; an intermediate gateway node 2; Receiving device 3.

The sending device 1 is configured to send messages to the receiving device 3 through the intermediate gateway node 2 and receive feedback information. Specifically, the message sending module 11 sends a message to the receiving device 3 through the intermediate gateway node 2. In the slow start phase, the sending device 1 sends a message to the receiving device 3 in an exponential growth manner, and the change of the message sending amount is 1, 2, 4, 8..., is an exponential growth; when the amount of packets sent reaches the predetermined threshold, in order to prevent link congestion, the amount of packets sent must be reduced, and the network enters the congestion avoidance stage, sending Device 1 sends packets to receiving device 3 in an additive growth manner, that is, the amount of packets sent increases by 1 each time. The feedback information receiving module 12 receives the congestion information fed back by the intermediate gateway node 2 and the link error information and message reception confirmation information fed back by the receiving device 3. If the feedback information receiving module 12 receives the congestion information, that is, the DRED-ECN feedback, it sends The device 1 reduces the amount of messages sent to the receiving device 3. If the feedback information receiving module 12 receives link error information, that is, multiple repeated messages receive confirmation information, the retransmission from the sending device 1 to the receiving device 3 is lost. message; if the feedback information receiving module 12 receives message reception confirmation information, the sending device 1 continues to send messages to the receiving device 3 .

Embodiment 1 of an adaptive congestion control system suitable for a satellite network uses the intermediate gateway node 2 to feed back congestion information and the receiving device 3 to feed back link error information, so that the network can identify the cause of packet loss, and correct link congestion and link error information. The resulting message loss is processed separately, thereby improving the throughput and fairness of the network, and reducing the transmission delay.

Fig. 5 is a structural diagram of Embodiment 2 of an adaptive congestion control system suitable for a satellite network according to the present invention. On the basis of Embodiment 1, the system further includes a message sending volume control module 13, which is connected with the message sending module 11 and the message sending module 13 respectively. The feedback information receiving module 12 is connected. The message sending volume control module 13 further controls the message sending volume of the message sending module according to the congestion information received by the feedback information receiving module 12 , the link error information or the message receiving confirmation information. If the feedback information receiving module 12 receives the link error information, the message transmission amount control module 13 controls the sending device 1 to retransmit the lost message to the receiving device 3 according to the original message sending rate, that is, fast retransmits the lost message. After the lost message is retransmitted, the sending device 1 is controlled to send the message to the receiving device 3 according to the original message sending rate and in an additive growth manner; if the feedback information receiving module 12 receives the congestion information, the message sending amount The control module 13 controls the sending device 1 to reduce the amount of messages sent to the receiving device 3; if the feedback information receiving module 12 receives the message reception confirmation information, the message sending amount control module 13 controls the sending device 1 to continue sending to the receiving device 3 Message; if the feedback information receiving module 12 does not receive any information, the message sending amount control module 13 controls the sending device 1 to reduce the message sending amount to 1 and send messages to the receiving device 3 in an exponential growth manner.

Embodiment 2 of an adaptive congestion control system suitable for a satellite network uses the message transmission amount control module 13 to separately process message loss caused by link congestion and link bit errors. When the system knows that the message loss at this time is due to link If it is caused by a bit error, instead of reducing the amount of packets sent according to the traditional method, it enters the congestion avoidance stage according to the complete recovery algorithm, so that the throughput can be further improved and the transmission delay can be reduced.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be The scheme shall be modified or equivalently replaced without departing from the spirit and scope of the technical scheme of the present invention.

Claims (6)

1. An adaptive congestion control method suitable for a satellite network, wherein, comprising the steps of: The sending device sends messages to the receiving device in an exponential growth manner; The sending device receives the feedback information, if the feedback information is congestion information, the sending device reduces the amount of packets sent to the receiving device; if the feedback information is link error information, the sending device keeps the original sending Retransmit the lost message to the receiving device at the same rate; if the feedback information is message reception confirmation information, the sending device continues to send messages to the receiving device; If the sending device does not receive the feedback information after a predetermined period of time, the sending device will reduce the message sending amount to 1 and restart sending messages to the receiving device in an exponentially increasing manner. 2. The adaptive congestion control method suitable for satellite networks according to claim 1, wherein the sending device sends a message to the receiving device in an exponential growth mode and specifically includes the following steps: The sending device sends messages to the receiving device in an exponential growth manner; When the amount of message sending reaches a predetermined threshold, the sending device sends messages to the receiving device in an additive growth manner. 3. The adaptive congestion control method suitable for satellite networks according to claim 2, wherein the sending device reduces the amount of packets sent to the receiving device, specifically, the sending device reduces the amount of packets sent to the original Send half of the message volume and send messages to the receiving device in an additive growth manner. 4. The adaptive congestion control method suitable for satellite networks according to claim 1, 2 or 3, wherein said sending device is also included after retransmitting the lost message to the receiving device while maintaining the original sending rate A step of sending messages to the receiving device in an additive growth manner according to the original message sending volume. 5. An adaptive congestion control system suitable for satellite networks, comprising: The sending device is used to send messages and receive feedback information, specifically including a message sending module and a feedback information receiving module; the message sending module is used to send messages; the feedback information receiving module is used to receive the congestion information, the feedback information receiving module The link error code information and the message receiving confirmation information; the feedback information receiving module is connected with the message sending module; The intermediate gateway node is used to feed back the congestion information to the sending device and discard a certain amount of packets at the same time to alleviate the congestion situation; The receiving device is configured to receive the message sent by the sending device through the intermediate gateway node, and feed back link error information and message reception confirmation information to the sending device through repeated confirmation. 6. The adaptive congestion control system suitable for satellite networks according to claim 5, wherein the sending device further includes a message sending amount control module, which is used to receive the congestion information according to the feedback information receiving module Or the link error information controls the amount of messages sent by the message sending module.

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