CN102739569B - Gateway used in satellite communication and method for enhancing TCP performance - Google Patents

Abstract

The invention discloses a gateway used in satellite communication and a method for enhancing its TCP performance. The method includes: dividing the entire transmission path between a terminal on the ground and a terminal in space into several sections according to the characteristics of the transmission path, The satellite communication link section between the ground gateway and the space gateway in the several sections adopts the optimized TCP protocol, and the remaining several sections all adopt the TCP protocol; wherein, the optimized TCP protocol is suitable for long delay, high bit error Any protocol adopted for transmitting data on a path with asymmetric rate and bandwidth; the characteristics of the transmission path include: delay characteristics, bit error characteristics and channel symmetry characteristics. Based on the method, the satellite communication link between the ground gateway and the space gateway of the present invention adopts the SCPS-TP protocol to establish a TP connection for TP data transmission; disconnect the established TP connection. The traditional TCP transport protocol continues to be used on both sides of the gateway. The invention does not need to modify the original equipment, and is fully compatible with the TCP transmission protocol.

Description

A Gateway Used in Satellite Communications and Its TCP Performance Enhancement Method

technical field

The invention relates to a method for enhancing the transmission performance of the TCP protocol in the technical field of satellite communication, is applicable to the TCP transmission service based on the satellite communication, and specifically relates to a gateway used in the satellite communication and a method for enhancing TCP performance thereof.

Background technique

As satellites play an increasingly important role in modern communication infrastructure, the combination of satellite networks and IP networks is the hottest development trend in the field of satellite communications today. However, due to the long delay, high bit error rate and bandwidth asymmetry of the satellite network, which are different from the terrestrial network, the TCP protocol used in the terrestrial network cannot be well used in the satellite network. How to improve the transmission performance of TCP in satellite communication has become an important hotspot.

The current transport layer in the satellite communication link directly adopts the TCP protocol for end-to-end data transmission, which will bring the following problems:

1) The impact of long delays, the TCP protocol is a transmission protocol based on a confirmation feedback mechanism, which performs flow control and reliable transmission through confirmation information and a retransmission mechanism. If there is no confirmation information for a long time, the TCP protocol will consider that the data packet has been lost, and implement a retransmission mechanism. Since the typical satellite communication delay is about 540ms, this will cause non-stop retransmission of the TCP protocol, causing congestion of the communication link.

2) The impact of high bit error rate, the TCP protocol assumes that the communication quality is good and the bit error rate is very low. Therefore, there is no error control and recovery mechanism in the TCP protocol, and these are generally completed by the link layer or the application layer. Since there are high bit errors in actual satellite communication, and the TCP protocol cannot distinguish between data loss caused by network congestion or data loss caused by bit errors, TCP will always consider it to be caused by network congestion, thereby reducing TCP transmission. window, causing the transmission bandwidth to drop.

3) The influence of link asymmetry. The bandwidth in actual satellite communication is asymmetric, while the TCP protocol assumes that the transmission bandwidth is symmetric, and the asymmetric bandwidth will cause the decline of TCP transmission performance.

4) The impact of intermittent connection will cause TCP to repeatedly restart the connection or retransmit, thereby causing network congestion and hindering the application in satellite data transmission.

Based on the analysis of the above reasons, if the TCP protocol is used in the satellite communication link, many problems will be caused.

Therefore, in order to enhance the transmission performance of the existing TCP protocol and make it more suitable for the characteristics of satellite communication links, the technical means currently used mainly include the following:

The first solution: for high bit error rate, the link layer is improved, and various error correction codes are used, such as forward error correction (ECC) and automatic retransmission (ARQ), which can better reduce the bit error rate. However, the use of error control at the link layer will introduce data redundancy and reduce the utilization rate of bandwidth, and different transmission services require different coding schemes, which is difficult to unify. Moreover, it is necessary to modify the user's original network equipment, so this solution is very complicated in actual implementation.

The second solution: the way of TCP spoofing, which creates an illusion for the transmission source, so that the transmission source can continue to send the next data packet without waiting for the confirmation of the terminal. The main purpose is to overcome the impact of long delay on the slow start algorithm. In a network with a good link quality, the data transmission rate can be increased, but it is not suitable for a network with a poor link quality, especially in a satellite communication network. The method is still affected by the sliding window size and channel error, resulting in a decrease in data transmission rate.

The third solution: extend and improve the TCP protocol itself, such as using the US Space Data System Advisory Committee to "tailor-made" the space communication protocol transmission protocol SCPS-TP for space communication, which will cause the improved TCP protocol to be different from the original The problem of compatibility of transmission protocols, and simply using SCPS-TP to improve TCP transmission performance will require users to modify all existing network equipment, including user terminals and gateways, which is complex and unfeasible to implement.

Contents of the invention

The purpose of the present invention is, for overcoming the problem that the transmission performance of TCP agreement on the satellite communication link descends, the problem of bandwidth utilization rate is low, proposes a kind of gateway that is used in satellite communication and the method for TCP performance enhancement thereof.

In order to achieve the above object, the present invention provides a method for enhancing the performance of gateway TCP in satellite communication, including: dividing the entire transmission path between a terminal on the ground and a terminal in space into several sections according to the characteristics of the transmission path , the satellite communication link section between the ground gateway and the space gateway in the several sections adopts the optimized TCP protocol, and the remaining several sections all adopt the TCP protocol.

Wherein, the optimized TCP protocol is any protocol suitable for transmitting data on a path with long delay, high bit error rate and bandwidth asymmetry; the characteristics of the transmission path include: delay feature, bit error feature and channel symmetry features. Delay characteristics, the one-way transmission delay of low-orbit satellites is 20-25ms, that of mid-orbit is 110-130ms, and that of geostationary orbit is 250-280ms. It is also affected by factors such as inter-satellite routing, on-board processing, and buffering. Bit error characteristics, the bit error rate of the satellite channel is about 10-6 data level, and various random factors (such as star eclipse and rain attenuation) will cause burst errors in the channel. Channel asymmetry. Due to the limitation of antenna size and transmission power, the satellite system has a large bandwidth asymmetry in the forward channel and reverse channel.

In the above technical solution, the ground gateway and the space gateway adopt the method of modifying the destination IP address and destination port number of the received message and the source IP address and source port number of the sent message to establish a pseudo-transmission connection and obtain the transmission message ; Wherein, the received message and sent message include: TCP message or SCPS-TP message.

As an optimal technical solution, the present invention sets between the terminal user on the ground and the gateway located on the ground as the first section of transmission path, and this section adopts the TCP protocol; between the gateway on the ground and the gateway located in space The satellite communication link is set as the second transmission path, and the SCPS-TP protocol is used as the optimized TCP protocol; the third transmission path is set between the second gateway and the end user in space, and the TCP protocol is used.

Wherein, the satellite transmission path adopts the SCPS-TP protocol to establish a pseudo-transmission connection and obtains the method for transmitting messages comprising: a step of establishing a connection, the second section of the transmission path described in this step adopts the SCPS-TP protocol to establish a TP connection, And record the connection information; the step of transmitting data, the second transmission path described in this step adopts SCPS-TP protocol to carry out TP data transmission; the step of disconnecting, the second transmission path described in this step adopts The SCPS-TP protocol disconnects the established TP connection.

In the above technical solution, the step of establishing a TP connection further includes:

Step 301: the step of intercepting the SYN message, the gateway intercepts the TCP message sent by the terminal connected to it, judges whether it is a SYN message, if it is, then enters the next step, if not, then discards;

Step 302, the step of storing the SYN message, recording and storing the TCP connection information contained in the intercepted SYN message;

Step 303: the step of modifying the SYN message, modifying the address of the intercepted SYN message, modifying the destination IP address and destination port number in the message to the corresponding interface of the gateway connected to the terminal that initiated the TCP connection request IP address and service port number;

Step 304: The gateway that intercepts the SYN message or initiates an SCPS-TP connection request to another gateway connected to the destination terminal to establish a TP connection, and initiates an SCPS-TP connection request to the connection destination terminal according to the connection information recorded in step 302 , establishing a TP connection with the gateway connected to the destination terminal;

Wherein, the two gateways are a ground gateway and a space gateway respectively.

Optimally, after the step 303, it also includes:

The pseudo-response step is used for the gateway that intercepts the SYN message to send pseudo-confirmation information for connection establishment to the connection initiating terminal, and completes the TCP connection handshake between the connection initiating terminal and the gateway that intercepts the SYN message.

In the above technical solution, the step of transmitting data further includes:

Step 401: the gateway connected to the data sending terminal intercepts the TCP message, and judges whether it is an effective TCP data message to be transmitted according to the connection information recorded in step 302, if so, then enters the next step, if not, then discards this datagram;

Step 402: Modify the destination IP address and destination port number of the TCP data message to be transmitted, and modify the destination address and destination port number to the IP address and port number of the corresponding port of the gateway connected to the data sending terminal;

Step 403: Convert the received TCP data message into a TP data message, and transmit the data message from another port of the gateway connected to the data sending terminal to another gateway connected to the data message receiving terminal;

Wherein, the two gateways are a ground gateway and a space gateway respectively.

Optimized, before the step 402 also includes:

The step of judging whether there is a TP connection is used to find the recorded connection information according to the destination address and the destination port number of the data message, and judge whether the gateway connected to the data sending terminal has a TP connection leading to the destination terminal and the port number, if If yes, enter step 403; otherwise, discard the message.

After the step 402, it also includes:

The step of false response is used for the gateway that intercepts the data message to send false confirmation information that the data has been sent to the destination terminal to the data message sending terminal.

In the above technical solution, the step of disconnecting further includes:

Step 501: the step of intercepting the FIN message, the gateway intercepts the TCP message sent by the disconnection initiating terminal, judges whether it is a FIN message, and if so, enters the next step;

Step 502: the step of modifying the FIN message, modifying the address of the intercepted FIN message, and modifying the destination IP address and destination port number contained in the message to the corresponding interface of the gateway connected to the terminal that initiated the TCP disconnection request IP address and service port number on the website;

Step 503: The gateway that intercepts the FIN message initiates an SCPS-TP disconnection request to another gateway that has proposed a TP connection to disconnect the existing TP connection, and converts the TCP disconnection request message into SCPS-TP FIN message, initiate a TP disconnection request to another gateway that establishes a TP connection with the gateway through another interface of the gateway connected to the terminal that initiates the TCP disconnection request;

Wherein, the two gateways are a ground gateway and a space gateway respectively.

Optimized, the step 502) also includes before:

The step of judging whether the TP connection exists is used for judging whether there is a TP connection to be disconnected, if yes, enter the step 502, otherwise discard the FIN message.

After the step 503), it also includes:

The step of false response: it is used to send false confirmation information that the connection has been disconnected to the disconnection initiating terminal.

In the above technical solution, the pseudo-response message needs to modify the source IP address and source port number to the recorded destination IP address and destination port number.

The present invention also provides a kind of gateway that is used in satellite communication based on the transmission method of above segment, comprises: The packet filter module that is used to intercept TCP message and the pseudo-response module that is used to send pseudo-acknowledgment information, it is characterized in that, The gateway also contains:

The recording module is used to record the TCP connection information contained in the connection establishment request message, and saves the TP connection information established in one-to-one correspondence with the TCP connection; the modification module is used to record the SYN message and the FIN message contained in the TCP message modifying the destination address and destination port number with the data message; and the protocol conversion module, which is used to convert the TCP connection request into an SCPS-TP connection request to establish a TP connection, and is used to convert the TCP data message to be transmitted into TP The data message is transmitted, which is used to convert the FIN message of TCP disconnection into the request of TP disconnection to disconnect the established TP connection, or perform the opposite protocol conversion.

Optimally, the gateway further includes two caches, one for storing received TCP data packets, and the other for storing data to be converted into TP packets.

The advantages of the present invention are:

1) Using the technology of protocol conversion, the traditional TCP protocol is converted into a transmission protocol (such as SCPS-TP protocol) suitable for satellite communication link connection, and the protocol conversion gateway performs transparent protocol conversion. Since the traditional TCP protocol is still used at both ends, there is no need to modify the original equipment at both ends of the application, reducing technical and cost risks, and facilitating the promotion of future applications.

2) Use a false response to pretend to be the destination terminal, so that the transmission data source can continue to send the next data packet without waiting for the confirmation of the destination terminal, and increase the sending rate of the TCP transmission data source.

3) Through the TCP segmentation technology, it overcomes the problem that the SCPS-TP protocol is not feasible in the specific implementation due to the heavy workload caused by the end-to-end full-process use of the SCPS-TP protocol. Using the SCPS-TP protocol at the middle end to enhance the TCP transmission performance can effectively use the advantages of the SCPS-TP protocol, make full use of the satellite channel, and improve the data throughput and link utilization rate of transmission.

4) Both ends of the gateway of the present invention are fully compatible with the original TCP protocol, without modifying the existing network equipment.

Description of drawings

The working environment schematic diagram of Fig. 1 the present invention;

Fig. 2 is a flow chart of all steps further included in the step of establishing a connection included in a gateway in satellite communication and a method for enhancing TCP performance thereof of the present invention;

Fig. 3 is a flow chart of all steps further included in the step of data transmission included in a gateway in satellite communication and its TCP performance enhancing method of the present invention;

Fig. 4 is a flow chart of all the steps included in the step of disconnection included in the gateway used in satellite communication and its TCP performance enhancing method of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Referring to schematic diagram 1, the satellite communication link refers to the communication link between the ground station and the communication satellite (or space station); it is assumed that the terminal on the ground and the terminal in space are the first terminal and the second terminal respectively, and are connected to the first terminal The gateway and the gateway connected to the second terminal are respectively the first gateway and the second gateway. Between the first terminal and the first gateway is the first transmission path. The transmission layer of this path adopts the TCP transmission protocol, which corresponds to the connection between the terminal and the gateway on the ground station or the terminal and the gateway on the communication satellite (or space station) in the actual working environment. The transmission path between; the path between the first gateway and the second gateway is the second transmission path, corresponding to the satellite communication channel between the ground station and the communication satellite (or space station) in the actual environment; between the second gateway and the second terminal The path between is the third transmission path, which corresponds to the transmission path opposite to the first transmission path, that is, if the terminal and the gateway included in the first transmission path are located at the ground station, then the terminal and the gateway there are located on the communication satellite (or space station), If the terminals and the gateway at both ends of the first transmission path are located on the communication satellite (or space station), then the second terminal and the second gateway there are located at the ground station. In the second transmission path, the SCPS-TP protocol or the STP (Satellite Transport Protocol) protocol is used as an example for illustration. The specific implementation steps are as follows:

① Establish a connection.

When the first terminal initiates a TCP connection request to the second terminal and passes through the first gateway, the gateway 1 intercepts the SYN message through the packet filtering module before the routing judgment, and records the TCP connection information (the source IP address of the connection) for the intercepted SYN message. IP address and source port number, and destination IP address and destination port number). After recording, modify the destination IP address and destination port number of the SYN message to the IP address and service port number on interface A of the first gateway. The SYN packet is forwarded to the protocol conversion service program on the first gateway. The connection handshake with the first terminal is completed by the protocol conversion service program. Then the protocol conversion service program initiates an SCPS-TP connection request (or STP connection request) through interface B to the recorded destination IP address and destination port number, that is, the IP address and port number of the second terminal.

When the SCPS-TP connection request (or STP connection request) passes through the second gateway, the packet filter module of the second gateway intercepts the SYN message (or STP connection request message) of SCPS-TP, and records the SCPS-TP connection information ( or STP connection request information), including source IP address and source port number, and destination IP address and destination port number. After recording, modify the destination IP address and the destination port number of the SYN message (or STP connection request message) of SCPS-TP, modify the IP address and the service port number on the interface B of the second gateway, and use the SCPS-TP The SYN message (or the STP connection request message) is forwarded to the protocol conversion service program on the second gateway, and the protocol conversion program completes the handshake with the gateway 2 . Then the protocol conversion program initiates a TCP connection request through interface A to the recorded destination IP address and destination port number, that is, the IP address and port number of the second terminal.

②Data transmission.

After receiving the TCP data message sent by the first terminal through the packet filtering module, the first gateway judges whether there is a connection request record, and discards it if it does not exist. Exist, then modify the purpose IP address and the purpose port number of the TCP data message, revise to the IP address and the service port number of the A port on the first gateway, and carry out pseudo-response to the TCP data message when receiving, so that the first A terminal considers that the TCP datagram has been sent to the second terminal. Then, the protocol conversion program of the first gateway converts the received TCP data message into an SCPS-TP data message (or STP data message), and sends it to the second terminal through the B port.

After the second gateway receives the SCPS-TP data message (or STP data message) sent by the first gateway through the packet filtering module, the destination IP address and the destination port of the SCPS-TP data message (or STP data message) modify the IP address and service port number of the B port of the second gateway, and carry out a pseudo-response to the SCPS-TP data message (or STP data message) when it is received, so that the first gateway thinks that the SCPS-TP data message (or STP data message) The TP datagram (or STP datagram) has been sent to the second terminal. The protocol conversion program of the second gateway converts the received SCPS-TP data message (or STP data message) into a TCP data message, and sends it to the second terminal through interface A.

③ Disconnect

The first terminal sends a request to disconnect the TCP connection to the second terminal. When the first gateway passes through the first gateway, the first gateway intercepts the TCP FIN message through the packet filtering module to determine whether there is a connection request record, and discard it if it does not exist. Exist, then modify the destination IP address and destination port number of the FIN message of TCP, modify the IP address and service port number of the A port of the first gateway, and then convert it into the FIN message of SCPS-TP by the protocol conversion program (or STP disconnection request), initiate a disconnection request to the second terminal through interface B.

After the second gateway receives the FIN message of SCPS-TP (or the disconnection request of STP) sent by the first gateway, the destination IP address and purpose of the FIN message of SCPS-TP (or the disconnection request of STP) Modify the port number to the IP address and service port number of port B of the second gateway, and then convert it into a TCP FIN message by the protocol conversion program of the second gateway, and initiate a disconnection request to the second terminal through interface A .

Wherein, the functions of the first gateway and the second gateway described above are equivalent, that is, the steps of establishing a connection, transmitting data and disconnecting can be initiated by the second terminal through the second gateway, and the specific working process is as above.

Fig. 2, Fig. 3, Fig. 4 are work flowcharts of the present invention. Because the functions of the first gateway and the second gateway are symmetrical. The flowchart mainly takes one of the gateways as an example, and takes the satellite communication link segment using the SCPS-TP protocol as an example.

In the flow chart of FIG. 2 , packet filtering is to filter input network data packets to obtain TCP packets. After the packet is obtained, it is judged whether it is a TCP SYN packet. Connection information (source address and port number, destination address and port number) is recorded in connection information management. Address modification completes the modification of the destination address and port number. The pseudo-acknowledgment responds to the received message. Establish an SCPS-TP connection, and initiate a TP connection request to the destination address and port number recorded in the connection information management.

In the flow chart of FIG. 3 , packet filtering is to filter input network data packets to obtain TCP packets. After the packet is obtained, it is judged whether it is a TCP data packet. The input data link and the output data link are two internal caches, which are used to cache messages and improve the performance of data transmission. It is judged whether there is connection information in the connection information management, if there is no connection information, it is discarded, and if there is, further processing is performed. Address modification completes the modification of the destination address and port number. The pseudo-acknowledgment responds to the received message. Finally, it is converted into an SCPS-TP message for data transmission.

In the flow chart of FIG. 4 , packet filtering is to filter input network data packets to obtain TCP packets. After the packet is obtained, it is judged whether it is a TCP FIN packet. It is judged whether there is connection information in the connection information management, if there is no connection information, it is discarded, and if there is, further processing is performed. Address modification completes the modification of the destination address and port number. The pseudo-acknowledgment responds to the received message. Finally, convert to FIN of SCPS-TP for data transmission.

It should be noted that the embodiments of the present invention described above are not limiting. Those skilled in the art should understand that any modification or equivalent replacement of the technical solution of the present invention does not depart from the spirit and scope of the technical solution of the present invention, and should be covered by the claims of the present invention.

Claims (10)

1. A method for gateway TCP performance enhancement in satellite communications, comprising: The entire transmission path between the terminal on the ground and the terminal in space is divided into several sections according to the characteristics of the transmission path, and the satellite communication link section between the ground gateway and the space gateway in the several sections adopts the optimized TCP protocol , and the rest of the segments all use the TCP protocol; Wherein, the optimized TCP protocol is any protocol suitable for transmitting data on a path with long delay, high bit error rate and bandwidth asymmetry; the characteristics of the transmission path include: delay feature, bit error feature and channel symmetry features; The first section of transmission path is set between the terminal user on the ground and the ground gateway, and this section adopts the TCP protocol; the satellite communication link between the ground gateway and the gateway in space is set as the second section of transmission path , the SCPS-TP protocol is used as the optimized TCP protocol; the third transmission path is set between the space gateway and the end users located in the space, and the TCP protocol is adopted. Wherein, the method for establishing a pseudo-transmission connection using the SCPS-TP protocol and obtaining a transmission message includes: The step of establishing a connection, the second transmission path described in this step adopts the SCPS-TP protocol to establish a TP connection, and record the connection information; The step of transmitting data, the second section of transmission path described in this step adopts SCPS-TP protocol to carry out TP data transmission; The step of disconnecting, the second transmission path described in this step adopts the SCPS-TP protocol to disconnect the established TP connection; The step of establishing a TP connection further includes: Step 301: the step of intercepting the SYN message, the gateway intercepts the TCP message sent by the terminal connected to it, judges whether it is a SYN message, if it is, then enters the next step, if not, then discards; Step 302, the step of storing the SYN message, recording and storing the TCP connection information contained in the intercepted SYN message; Step 303: the step of modifying the SYN message, modifying the address of the intercepted SYN message, modifying the destination IP address and destination port number in the message to the corresponding interface of the gateway connected to the terminal that initiated the TCP connection request IP address and service port number; Step 304: The gateway that intercepts the SYN message or initiates an SCPS-TP connection request to another gateway connected to the destination terminal to establish a TP connection, and initiates an SCPS-TP connection request to the connection destination terminal according to the connection information recorded in step 302 , establish a TP connection with the gateway connected to the destination terminal Among them, the two gateways are ground gateway and space gateway respectively. 2. the method for the gateway TCP performance enhancement in satellite communication according to claim 1, it is characterized in that, described ground gateway and space gateway adopt the destination IP address and destination port number of revising received message and send message The method of source IP address and source port number is used to establish a pseudo-transmission connection and obtain transmission packets; Wherein, the received message and the sent message include: a TCP message or an SCPS-TP message. 3. the method for the gateway TCP performance enhancement in satellite communication according to claim 1, is characterized in that, also comprises after described step 303: The pseudo-response step is used for the gateway that intercepts the SYN message to send pseudo-confirmation information for connection establishment to the connection initiating terminal, and completes the TCP connection handshake between the connection initiating terminal and the gateway that intercepts the SYN message. 4. the method for the gateway TCP performance enhancement in satellite communication according to claim 1, is characterized in that, the step of described transmission data further comprises: Step 401: the gateway connected to the data sending terminal intercepts the TCP message, and judges whether it is an effective TCP data message to be transmitted according to the connection information recorded in step 302, if so, then enters the next step, if not, then discards this datagram; Step 402: Modify the destination IP address and destination port number of the TCP data message to be transmitted, and modify the destination address and destination port number to the IP address and port number of the corresponding port of the gateway connected to the data sending terminal; Step 403: Convert the received TCP data message into a TP data message, and transmit the data message from another port of the gateway connected to the data sending terminal to another gateway connected to the data message receiving terminal; Among them, the two gateways are ground gateway and space gateway respectively. 5. the method for the gateway TCP performance enhancement in satellite communication according to claim 4, is characterized in that, also comprises before described step 402: The step of judging whether there is a TP connection is used to find the recorded connection information according to the destination address and the destination port number of the data message, and judge whether the gateway connected to the data sending terminal has a TP connection leading to the destination terminal and the port number, if If yes, enter step 403; otherwise, discard the message. 6. the method for the gateway TCP performance enhancement in satellite communication according to claim 4, is characterized in that, also comprises after described step 402: The step of false response is used for the gateway intercepting the TCP message to send false confirmation information that the data has been sent to the destination terminal to the terminal sending the data message. 7. the method for the gateway TCP performance enhancement in satellite communication according to claim 1, is characterized in that, the step of described disconnection further comprises: Step 501: the step of intercepting the FIN message, the gateway intercepts the TCP message sent by the disconnection initiating terminal, judges whether it is a FIN message, and if so, proceeds to the next step; Step 502: the step of modifying the FIN message, modifying the address of the intercepted FIN message, and modifying the destination IP address and destination port number contained in the message to the corresponding interface of the gateway connected to the terminal that initiated the TCP disconnection request IP address and service port number on the website; Step 503: The gateway that intercepts the FIN message initiates an SCPS-TP disconnection request to another gateway that has established a TP connection to disconnect the existing TP connection, and converts the TCP disconnection request message into SCPS-TP FIN message, initiate a TP disconnection request to another gateway that establishes a TP connection with the gateway through another interface of the gateway connected to the terminal that initiates the TCP disconnection request; Among them, the two gateways are ground gateway and space gateway respectively. 8. the method for the gateway TCP performance enhancement in satellite communication according to claim 7, is characterized in that, also comprises before described step 502: The step of judging whether the TP connection exists is used for judging whether there is a TP connection to be disconnected, if yes, enter the step 502, otherwise discard the FIN message. 9. the method for the gateway TCP performance enhancement in satellite communication according to claim 7, is characterized in that, also comprises after described step 503: The step of false response: it is used to send false confirmation information that the connection has been disconnected to the disconnection initiating terminal. 10. according to claim 3, the method for the gateway TCP performance enhancement in satellite communication described in 6 or 9, it is characterized in that, described pseudo-response message needs to revise source IP address and source port number for the purpose of record IP address and destination port number.