WO2016119464A1

WO2016119464A1 - Method and corresponding gateway for implementing tcp transmission in satellite network environment

Info

Publication number: WO2016119464A1
Application number: PCT/CN2015/089060
Authority: WO
Inventors: 常伟; 唐雄; 刘亮; 麦伟鹏; 晏文彬
Original assignee: 中兴通讯股份有限公司
Priority date: 2015-01-26
Filing date: 2015-09-07
Publication date: 2016-08-04
Also published as: CN105897665A; CN105897665B

Abstract

Disclosed are a method and a corresponding gateway for implementing TCP transmission in a satellite network environment. The method comprises: a gateway that is in a PEP and that is connected to a client performs the following processing: intercepting a TCP connection request sent by the client to a server, extracting first connection information from the TCP connection request and sending a pseudo response to the client, and establishing a first TCP connection with the client; using the first connection information as a data part and encapsulating a TMSG header, generating a packet for requesting the establishment of a connection and sending, through a satellite link, the packet to a peer-end gateway connected to the server, the TMSG header carrying a first TCP connection identifier; and after a connection establish success response packet returned by the peer-end gateway is received, recording a second TCP connection identifier carried by the TMSG header and associating the second TCP connection identifier with the first TCP connection identifier.

Description

Method for implementing TCP transmission in satellite network environment and corresponding gateway

Technical field

Embodiments of the present invention relate to, but are not limited to, satellite communications, and in particular, to a method for implementing TCP transmission based on a satellite network environment and a corresponding gateway.

Background technique

As satellite technology plays an increasingly important role in modern communication infrastructure, the combination of satellite networks and terrestrial IP networks is the hottest trend in satellite communications today. TCP (Transmission Control Protocol) is a connection-oriented transport layer protocol that provides reliable data transmission to related applications. According to statistics, more than 95% of data streams on the Internet currently use TCP as a transport protocol. However, when the TCP protocol is applied to the satellite network environment, the satellite channel is different from the inherent characteristics of the terrestrial link, which seriously affects the performance of the TCP and reduces the utilization of the satellite channel bandwidth.

Many studies have been carried out on how to improve the performance of TCP in the satellite network environment. The method for improving the TCP performance in the satellite system in the related art mainly adopts the method of PEP (Performe Enhancement Proxy), which is divided into single-ended and Both ends. The double-ended PEP includes two gateways respectively placed at the two ends of the satellite network. As shown in FIG. 1 , all the TCP connections are divided into three segments: the server and the primary PEP (set in the gateway connected to the server) are connected. The primary station PEP and the small station PEP (set in the gateway connected to the client) are connected, and the small station PEP is connected to the client. The double-ended PEP scheme does not modify the protocol stack and application of the communication parties. However, in order to adapt to the characteristics of the satellite link, the two gateways use other protocols than TCP for data transmission. In this case, how to implement the client and TCP transmission between servers is a technical problem that needs to be solved urgently.

Summary of the invention

The following is an overview of the topics detailed in this document. This Summary is not intended to limit the scope of the claims.

The embodiment of the invention provides a method for implementing TCP transmission in a satellite network environment, which is applied to a gateway connected to a client in a double-end acceleration proxy PEP, and the method includes the following connection establishment processing:

Intercepting a TCP connection request sent by the client to the server, extracting the first connection information therefrom, and sending a pseudo response to the client, establishing a first TCP connection with the client;

And using the first connection information as a data part and encapsulating the conversion message TMSG header, generating a message requesting to establish a connection and sending the message to the opposite gateway connected to the server by using a satellite link, where the TMSG header is carried by the identifier Determining a first TCP connection identifier of the first TCP connection;

After receiving the response message that the connection is successfully established by the peer gateway, the second TCP connection identifier carried in the TMSG header is recorded and associated with the first TCP connection identifier, where the second TCP connection identifier is The identifier of the TCP connection established between the peer gateway and the server.

Optionally, the TMSG header includes a message type, a connection identifier, and a message length field, where the TMSG header length is smaller than a length of the TCP header.

Optionally, the method further comprises the following processing of data transmission:

Intercepting and responding to the TCP data packet sent by the client to the server through the first TCP connection, extracting a data part from the TCP data packet, and encapsulating the TMSG header, and generating the generated data transmission message through the satellite Sending a link to the peer gateway, the TMSG header carrying the second TCP connection identifier associated with the first TCP connection identifier; and

Receiving a data transmission message from the satellite link, where the connection identifier of the TMSG header is the first TCP connection identifier, extracting a data part from the data transmission message and encapsulating a corresponding TCP header, and generating a TCP A data message is sent to the client over the first TCP connection.

Optionally, the method further includes the following disconnection processing:

A communication interruption of the first TCP connection is detected;

Transmitting, by the satellite link, a packet requesting to close the connection to the peer gateway, where the TMSG header carries the second TCP connection identifier;

After receiving the response message that the connection returned by the peer gateway is successfully closed, the first TCP connection is disconnected.

Optionally, the process of establishing the connection further includes: connecting the first TCP connection with the Satellite link association;

The method also includes the following process of disconnection: detecting that the satellite link is down, disconnecting all TCP connections associated with the satellite link.

The embodiment of the invention further provides a gateway for connecting to a client in a double-ended acceleration proxy PEP, comprising a user side protocol entity and a first satellite side protocol entity, wherein:

The user side protocol entity includes an underlying packet filtering module and an upper layer socket Socket server;

The packet filtering module includes:

The reverse forwarding unit is configured to intercept the connection request message and the ACK message sent when the client establishes a TCP connection with the server, and replace the destination IP address and the destination port in the packet with the IP address and port of the Socket server. Sending to the Socket server; wherein, when the connection request message is intercepted, the first connection information including the source IP address, the source port, the destination IP address, and the destination port is also recorded and sent to the Socket server;

a forward forwarding unit, configured to replace the source IP address and the source port in the ACK packet sent by the Socket server to the client with the destination IP address and the destination port in the first connection information, and send the The client;

The Socket server includes: a first connection establishing module, configured to: after receiving the connection request message and the first connection information sent by the packet filtering module, send an ACK message to the client; and send the packet filtering module After the ACK message, the first TCP connection with the client is established, and a first TCP connection identifier is generated to notify the first satellite side protocol entity that the first TCP connection is successfully established, and the first connection information is carried. ;

The first satellite side protocol entity includes: a second connection establishing module, configured to: after receiving the notification that the first TCP connection is successfully established by the Socket server, using the first connection information as a data part and encapsulating the conversion message TMSG a header, generating a message requesting to establish a connection and transmitting the message to the opposite gateway through a satellite link, the TMSG header carrying the first TCP connection identifier; and being configured to receive the peer gateway to return through the satellite link After establishing a successful response message, the second TCP connection identifier carried in the TMSG header is recorded and associated with the first TCP connection identifier. The second TCP connection identifier is an identifier of a TCP connection established by the peer gateway and the server.

Optionally, the TMSG header encapsulated by the second connection establishing module of the first satellite side protocol entity includes a message type, a connection identifier, and a message length field, where the TMSG header length is smaller than a length of the TCP header.

Optionally, the reverse forwarding unit in the packet filtering module is further configured to intercept the passed TCP data packet, where the connection information matches the first connection information, where the TCP data packet is from The first TCP connection, the destination IP address and the destination port in the TCP data packet are replaced with the IP address and port of the Socket server, and sent to the Socket server;

The Socket server further includes: a message processing module, configured to receive the TCP data packet from the first TCP connection and send a TCP response message;

The forward forwarding unit in the packet filtering module is further configured to replace the source IP address and the source port in the TCP response message sent by the Socket server to the client with the destination IP in the first connection information. After the address and the destination port are sent to the client;

The first satellite side protocol entity further includes: a first packet sending and receiving module, configured to encapsulate a TMSG header before the data portion of the TCP data packet from the first TCP connection, and the generated data sending message passes the A satellite link is sent to the correspondent gateway, and the TMSG header carries the second TCP connection identifier associated with the first TCP connection identifier.

Optionally, the first packet transceiver module of the first satellite side protocol entity is further configured to receive a data transmission message sent to the client from the satellite link;

The packet processing module in the Socket server is further configured to identify a data transmission message received by the first satellite side protocol entity, where the connection identifier of the TMSG header is the first TCP connection identifier, then the data is sent from the data. Extracting a data part in the sending message and encapsulating a corresponding TCP header, and the generated TCP data message is sent to the client through the first TCP connection;

The forward forwarding unit in the packet filtering module is further configured to replace the source IP address and the source port in the TCP data packet sent by the Socket server to the client with the destination IP in the first connection information. After the address and destination port are sent to the client.

Optionally, the Socket server further includes: a first connection maintenance module, configured to notify the first satellite side protocol entity that the first TCP connection protocol entity is interrupted when detecting that the first TCP connection communication is interrupted Disconnecting the TCP connection; and after receiving the notification that the connection of the first satellite side protocol entity is successfully closed, disconnecting the first TCP connection;

The first satellite side protocol entity further includes: a second connection maintenance module, configured to send a request to the peer gateway to close by using the satellite link after receiving the notification that the first TCP connection is interrupted by the Socket server The connected message, wherein the TMSG header carries the second TCP connection identifier; and is configured to notify the Socket server that the connection is successfully closed after receiving the response message that the connection returned by the peer gateway is successfully closed.

Optionally, the second connection maintenance module of the first satellite side protocol entity is further configured to send the notification that the satellite link is disconnected to the Socket server when detecting that the satellite link is disconnected ;

The first connection maintenance module of the Socket server is further configured to associate the first TCP connection with the satellite link; after receiving the notification that the satellite link is disconnected, the node is associated with the satellite link All TCP connections are broken.

The embodiment of the invention further provides a method for implementing TCP transmission in a satellite network environment, which is applied to a gateway connected to a server in a double-end acceleration proxy PEP, and the method includes the following connection establishment processing:

After receiving the packet of the connection establishment request sent by the peer gateway connected to the client via the satellite link, recording the first TCP connection identifier carried by the switching message TMSG header and the client carried by the data part and the pair The first connection information of the first TCP connection established by the end gateway, where the first TCP connection identifier is used to identify the first TCP connection;

Establishing a second TCP connection with the server, and after the connection is established, returning a connection establishment success message to the opposite gateway through the satellite link, where the TMSG header carries the identifier for identifying the second TCP connection. a second TCP connection identifier; associating the second TCP connection identifier with the first TCP connection identifier.

Receiving, by the server, the TCP data packet sent to the client by using the second TCP connection, responding, extracting the data part from the TCP data packet, and encapsulating the TMSG header, generating a data transmission packet and passing the packet Sending the satellite link to the peer gateway, the TMSG header carrying the first TCP connection identifier associated with the second TCP connection identifier; and

Receiving, by the satellite link, a data transmission message sent to the server, where the connection identifier carried by the TMSG header is the second TCP connection identifier, extracting a data part from the data transmission message and encapsulating The corresponding TCP header, the generated TCP data message is sent to the server through the second TCP connection.

Optionally, the method further includes the following disconnection processing:

A communication interruption of the second TCP connection is detected;

Transmitting, by the satellite link, a packet requesting to close the connection to the peer gateway, where the TMSG header carries the first TCP connection identifier;

After receiving the response message that the peer gateway returns a successful connection returned by the satellite link, the second TCP connection is disconnected.

Optionally, the process of establishing the connection further includes: associating the second TCP connection with the satellite link;

The method also includes the following process of disconnection: detecting that all of the TCP connections associated with the satellite link are disconnected after the satellite link is disconnected.

The embodiment of the invention further provides a gateway for connecting to a server in a double-end acceleration proxy PEP, comprising a server side protocol entity and a second satellite side protocol entity, wherein:

The second satellite side protocol entity includes: a third connection establishing module configured to: after receiving the message of the connection establishment request sent by the peer gateway connected to the client via the satellite link, record the message carried by the converted message TMSG header Corresponding to the first TCP connection identifier and the first connection information carried in the data part, and notifying the server side protocol entity to establish a second TCP connection with the server; the first connection information is established by the peer gateway and the client Connection information of the first TCP connection, the first TCP connection identifier is used to identify the first TCP connection;

The server side protocol entity includes: a fourth connection establishing module, configured to receive the establishment After the notification of the TCP connection, establishing the second TCP connection with the server, generating a second TCP connection identifier for identifying the second TCP connection, and returning a connection establishment to the peer gateway by using the satellite link a successful response message carrying the second TCP connection identifier, and notifying the second satellite side protocol entity that the second TCP connection is successfully established, and carrying the second TCP connection identifier;

The third connection establishing module of the second satellite side protocol entity is further configured to: after receiving the notification that the second TCP connection is successfully established by the server side protocol entity, returning the connection establishment to the peer gateway by using the satellite link a successful response message, wherein the TMSG header carries the second TCP connection identifier; and the second TCP connection identifier is associated with the first TCP connection identifier.

Optionally, the server-side protocol entity further includes: a second packet sending and receiving module, configured to receive and respond to the TCP data packet sent by the server to the client by using the second TCP connection;

The second satellite side protocol entity further includes: a third packet sending and receiving module, configured to extract a data part from the TCP data packet received by the server side protocol entity, and encapsulate a TMSG header, and generate a data sending message. And transmitting, by the satellite link, the peer gateway, where the TMSG header carries the first TCP connection identifier associated with the second TCP connection identifier.

Optionally, the third message sending and receiving module of the second satellite side protocol entity is further configured to receive a data sending message sent to the server from the satellite link;

The second packet sending and receiving module of the server side protocol entity is further configured to identify a data sending message received by the second satellite side protocol entity, where the connection identifier carried by the TMSG head is the second TCP connection identifier. And extracting a data part from the data sending message and encapsulating a corresponding TCP header, and the generated TCP data message is sent to the server by using the second TCP connection.

Optionally, the TMSG header encapsulated by the third packet transceiver module of the second satellite side protocol entity includes a message type, a connection identifier, and a message length field, where the TMSG header length is smaller than a length of the TCP header.

Optionally, the server side protocol entity further includes: a third connection maintenance module, configured to notify the second satellite side protocol entity that the second TCP connection is interrupted when detecting that the communication of the second TCP connection is interrupted And disconnecting the second TCP connection after receiving the notification that the connection of the second satellite side protocol entity is successfully closed;

The second satellite side protocol entity further includes: a fourth connection maintenance module, configured to send a message requesting to close the connection to the opposite gateway through the satellite link after receiving the notification that the second TCP connection is interrupted, The TMSG header carries the first TCP connection identifier; and after receiving the response message that the connection returned by the peer gateway is successfully closed, the server side protocol entity is notified that the connection is successfully closed.

Optionally, wherein the fourth connection maintenance module of the second satellite side protocol entity is further configured to send the satellite link disconnection to the server side protocol entity when detecting that the satellite link is disconnected announcement of;

The third connection maintenance module of the server side protocol entity is further configured to associate the second TCP connection with the satellite link; and after receiving the notification that the satellite link is disconnected, the satellite chain All TCP connections associated with the road are broken.

In the dual-ended PEP scenario, the two gateways use TCP spoofing for servers and clients respectively, and implement TCP transmission between the client and the server without changing the protocol stack of the server and the client. Processing can also reduce bandwidth usage by replacing the TCP header with a simpler TMSG header.

Other aspects will be apparent upon reading and understanding the drawings and detailed description.

BRIEF abstract

1 is a schematic diagram of a typical satellite communication application scenario in accordance with an embodiment of the present invention;

2 is a flow chart of connection establishment of a method according to an embodiment of the present invention;

3 is a schematic diagram of a TMSG head structure according to an embodiment of the present invention;

4 is a flow chart of data transmission in a method according to an embodiment of the present invention;

FIG. 5 is a flowchart of a connection disconnection process according to a method of the embodiment of the present invention; FIG.

6 is a block diagram of a gateway connected to a client according to Embodiment 1 of the present invention;

7 is a flowchart of connection establishment of a method according to Embodiment 2 of the present invention;

8 is a flowchart of data transmission in a method according to Embodiment 2 of the present invention;

9 is a flowchart of a connection disconnection process of the method of the second embodiment of the present invention;

10 is a block diagram of a gateway connected to a server according to Embodiment 2 of the present invention;

11 is a schematic diagram of a protocol stack of each network element in an application example of the present invention.

Embodiments of the invention

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments of the present invention may be arbitrarily combined with each other.

Embodiment 1

The embodiment relates to a method for implementing TCP transmission in a satellite network environment, and is applied to a gateway connected to a client in a double-end acceleration proxy PEP.

As shown in FIG. 2, the method includes the following connection establishment process:

Step 110, intercepting a TCP connection request sent by the client to the server, extracting the first connection information therefrom, and sending a pseudo response to the client, and establishing a first TCP connection with the client;

Step 120: The first connection information is used as a data part, and a header of a conversion message (TMSG, a transport message interaction format) is encapsulated, and a message requesting to establish a connection is generated and sent to a pair connected to the server through a satellite link. End gateway, the TMSG header carries a first TCP connection identifier;

The first TCP connection identifier is used to identify the first TCP connection.

As shown in FIG. 3, the TMSG header of this embodiment includes a message type, a connection identifier, and a message length field, and the TMSG header length is smaller than the length of the TCP header. among them:

The message type includes the request to establish a connection message, the connection establishment success response message, the request to close the connection message, the connection success response message, the closing of all connection messages, the data transmission message, and the like, but the message name is not in the embodiment of the present invention. limit.

The connection identifier includes a first TCP connection identifier for identifying a first TCP connection between the client and the gateway, and a second TCP connection identifier for identifying a second TCP connection between the gateway and the server.

Message length – the length of the message, ie the length of the message including TMSG.

Step 130: After receiving the response message that the connection returned by the peer gateway is successfully established, record the response message. The second TCP connection identifier carried by the medium TMSG header is associated with the first TCP connection identifier.

The second TCP connection identifier is an identifier of a TCP connection established by the peer gateway and the server.

Optionally, the method in this embodiment further includes a process of transmitting data by using a gateway connected to the client, as shown in FIG. 4, including:

Step 210: intercepting and responding to the TCP data packet sent by the client to the server by using the first TCP connection, extracting the data part from the TCP data packet, and encapsulating the TMSG header, and the generated data transmission packet is passed. Sending the satellite link to the peer gateway, where the TMSG header carries the second TCP connection identifier associated with the first TCP connection identifier;

Step 220: Receive a data transmission message from the satellite link, where the connection identifier of the TMSG header is the first TCP connection identifier, extract a data portion from the data transmission packet, and encapsulate a corresponding TCP header. The generated TCP data message is sent to the client over the first TCP connection.

Optionally, the method in this embodiment further includes a process of disconnecting the gateway connected to the client, as shown in FIG. 5, including:

Step 310, detecting that the communication of the first TCP connection is interrupted;

Step 320, sending, by the satellite link, a packet requesting to close the connection to the peer gateway, where the TMSG header carries the second TCP connection identifier;

Step 330: After receiving the response message that the connection returned by the peer gateway is successfully closed, disconnect the first TCP connection.

If it is detected that the satellite link is down, the gateway connected to the client disconnects all TCP connections associated with the satellite link. Of course, prior to this, the first TCP connection needs to be associated with the satellite link after establishing the first TCP connection.

Correspondingly, the embodiment further provides a gateway for connecting to a client in a double-ended acceleration proxy PEP. As shown in FIG. 6, the user side protocol entity 10 and the satellite side protocol entity 20 are included, where:

The user side protocol entity 10 includes a packet filtering module 101 and an upper layer of an underlying layer (referring to a physical layer). Socket (socket) server 103 (TCP protocol layer);

The packet filtering module 101 includes:

The reverse forwarding unit 1011 is configured to intercept the connection request message and the ACK message sent when the client establishes a TCP connection with the server, and replace the destination IP address and the destination port in the packet with the IP address of the Socket server 103. After the port is sent to the Socket server 103, the first connection information including the source IP address, the source port, the destination IP address, and the destination port is also recorded and sent to the Socket server. 103; and

The forward forwarding unit 1013 is configured to replace the source IP address and the source port in the ACK packet sent by the Socket server 103 to the client with the destination IP address and the destination port in the first connection information, Sent to the client;

The Socket server 103 includes:

The connection establishing module 1031 is configured to: after receiving the connection request message and the first connection information sent by the packet filtering module 101, send an ACK message to the client; and receive the ACK message sent by the packet filtering module 101. After the first TCP connection is established, the first TCP connection is established, and the first TCP connection identifier is generated, and the first TCP connection is successfully established, and the first connection information is carried.

The satellite side protocol entity 20 includes:

The connection establishing module 201 is configured to: after receiving the notification that the first TCP connection establishment of the Socket server 103 is successful, using the first connection information as a data part and encapsulating the conversion message TMSG header, generating a message requesting to establish a connection and Sending to the peer gateway through a satellite link, the TMSG header carries the first TCP connection identifier; and is configured to receive a response message that the peer gateway successfully establishes a connection returned by the satellite link, Recording a second TCP connection identifier carried in the TMSG header and associating with the first TCP connection identifier, where the second TCP connection identifier is an identifier of a TCP connection established by the peer gateway and the server. Optionally, the TMSG header includes a message type, a connection identifier, and a message length field, where the TMSG header length is smaller than a length of the TCP header.

Optionally,

The reverse forwarding unit 1011 in the packet filtering module 101 is further configured to intercept the passed TCP data packet, and if the connection information matches the first connection information, the TCP datagram The text is from the first TCP connection, the destination IP address and the destination port in the TCP data packet are replaced with the IP address and port of the Socket server 103, and sent to the Socket server 103;

The Socket server 103 further includes:

The message processing module 1033 is configured to receive the TCP data packet from the first TCP connection and send a TCP response message;

The forward forwarding unit 1013 in the packet filtering module 101 is further configured to replace the source IP address and the source port in the TCP response message sent by the Socket server 103 to the client into the first connection information. After the destination IP address and the destination port are sent to the client;

The satellite side protocol entity 20 further includes:

The packet sending and receiving module 203 is configured to encapsulate the TMSG header before the data portion of the TCP data packet from the first TCP connection, and the generated data transmission packet is sent to the opposite gateway through the satellite link. The TMSG header carries the second TCP connection identifier associated with the first TCP connection identifier.

Optionally,

The message transceiver module 203 of the satellite side protocol entity 20 is further configured to receive a data transmission message sent to the client from the satellite link;

The message processing module 1033 in the Socket server 103 is further configured to identify a data transmission message received by the satellite side protocol entity 20, such as the connection identifier of the TMSG header being the first TCP connection identifier, Extracting a data part in a data transmission message and encapsulating a corresponding TCP header, and the generated TCP data message is sent to the client through the first TCP connection;

The forward forwarding unit 1013 in the packet filtering module 101 is further configured to replace the source IP address and the source port in the TCP data packet sent by the Socket server 103 to the client into the first connection information. After the destination IP address and destination port are sent to the client.

Optionally,

The Socket server 103 further includes:

The connection maintenance module 1035 is configured to notify the satellite side protocol entity 20 that the first TCP connection is interrupted when the first TCP connection communication interruption is detected; and after receiving the notification that the connection of the satellite side protocol entity 20 is successfully closed Disconnecting the first TCP connection;

The satellite side protocol entity 20 further includes:

The connection maintenance module 205 is configured to: after receiving the notification that the first TCP connection is interrupted by the Socket server, send, by using the satellite link, a message requesting to close the connection to the opposite gateway, where the TMSG header carries the And the second TCP connection identifier is configured to notify the Socket server 103 that the connection is successfully closed after receiving the response message that the connection returned by the peer gateway is successfully closed.

Optionally,

The connection maintenance module 205 of the satellite side protocol entity 20 is further configured to send a notification that the satellite link is disconnected to the Socket server 103 when detecting that the satellite link is disconnected;

The connection maintenance module 1035 of the Socket server 103 is further configured to associate the first TCP connection with the satellite link; after receiving the notification that the satellite link is disconnected, the node associated with the satellite link All TCP connections are broken.

Embodiment 2

The embodiment relates to a method for implementing TCP transmission in a satellite network environment, and is applied to a gateway connected to a server in a double-end acceleration proxy PEP.

As shown in FIG. 7, the method includes the following connection establishment process:

Step 410: After receiving the packet of the connection establishment request sent by the peer gateway connected to the client via the satellite link, record the first TCP connection identifier carried by the TMSG header and the client and the data part carried by the data part. The first connection information of the first TCP connection established by the peer gateway, where the first TCP connection identifier is used to identify the first TCP connection;

Step 420: Establish a second TCP connection with the server, and after the connection is established, return a connection response message to the peer gateway through the satellite link, where the TMSG header carries the identifier a second TCP connection identifier of the two TCP connections; associating the second TCP connection identifier with the first TCP connection identifier.

Optionally, the method further includes processing of data transmission, as shown in FIG. 8, including:

Step 510: After receiving the TCP data packet sent by the server to the client by using the second TCP connection, the system responds, extracts a data part from the TCP data packet, and encapsulates the TMSG header to generate a data transmission report. And sending, by the satellite link, the peer gateway, where the TMSG header carries the first TCP connection identifier associated with the second TCP connection identifier;

Step 520: Receive a data transmission message sent from the satellite link to the server, where the connection identifier carried by the TMSG header is the second TCP connection identifier, and extract data from the data transmission message. The corresponding TCP header is partially encapsulated, and the generated TCP data packet is sent to the server through the second TCP connection.

Optionally, the method may further include a process of disconnection, as shown in FIG. 9, comprising:

Step 610: The communication interruption of the second TCP connection is detected.

Step 620: Send, by the satellite link, a packet requesting to close the connection to the peer gateway, where the TMSG header carries the first TCP connection identifier;

Step 630: After receiving the response message that the peer gateway returns a successful connection returned by the satellite link, disconnect the second TCP connection.

If it is detected that the satellite link is disconnected, the gateway connected to the server disconnects all TCP connections associated with the satellite link. Of course, the gateway needs to associate the second TCP connection with the satellite link after establishing a second TCP connection.

Correspondingly, the embodiment further provides a gateway connected to the server in the double-ended acceleration proxy PEP. As shown in FIG. 10, the server side protocol entity 50 and the satellite side protocol entity 60 are included, where:

The satellite side protocol entity 60 includes:

The connection establishing module 601 is configured to: after receiving the packet of the connection establishment request sent by the peer gateway connected to the client via the satellite link, record the first TCP connection identifier carried in the TMSG header and the data part carried in the data packet a connection information, and notifying the server side protocol entity 50 to establish a second TCP connection with the server; the first connection information is connection information of the first TCP connection established by the peer gateway and the client, The first TCP connection identifier is used to identify the first TCP connection;

The server side protocol entity 50 includes:

The connection establishing module 501 is configured to: after receiving the notification of establishing the TCP connection, establish the second TCP connection with the server, and generate a second TCP connection identifier for identifying the second TCP connection, by using the The satellite link returns a response message that the connection establishment is successful to the peer gateway, carries the second TCP connection identifier, and notifies the satellite side protocol entity 60 that the second TCP connection is successfully established, and carries the second TCP connection. Identification

The connection establishing module 601 of the satellite side protocol entity 60 is further configured to: after receiving the notification that the second TCP connection is successfully established by the server side protocol entity, returning the connection to the peer gateway through the satellite link. a response message, wherein the TMSG header carries the second TCP connection identifier; and the second TCP connection identifier is associated with the first TCP connection identifier.

Optionally,

The server side protocol entity 50 further includes:

The packet sending and receiving module 503 is configured to receive a TCP data packet sent by the server to the client by using the second TCP connection, and respond;

The satellite side protocol entity 60 further includes:

The packet sending and receiving module 603 is configured to extract a data part from the TCP data packet received by the server side protocol entity, and encapsulate a TMSG header, and the generated data sending message is sent to the peer end by using the satellite link. a gateway, wherein the TMSG header carries the first TCP connection identifier associated with the second TCP connection identifier.

Optionally,

The message transceiver module 603 of the satellite side protocol entity 60 is further configured to receive a data transmission message sent to the server from the satellite link;

The packet sending and receiving module 503 of the server side protocol entity 50 is further configured to identify the data sending message received by the satellite side protocol entity 60, such as the connection identifier carried by the TMSG head being the second TCP connection identifier. And extracting a data part from the data sending message and encapsulating a corresponding TCP header, and the generated TCP data message is sent to the server by using the second TCP connection.

Optionally,

The TMSG header encapsulated by the message transceiver module 603 of the satellite side protocol entity 60 includes The message type, the connection identifier, and the message length field, the TMSG header length being less than the length of the TCP header.

Optionally,

The server side protocol entity 50 further includes:

The connection maintenance module 505 is configured to notify the satellite side protocol entity 60 that the second TCP connection is interrupted when the communication interruption of the second TCP connection is detected, and notify that the connection of the satellite side protocol entity 60 is closed successfully. Afterwards, disconnecting the second TCP connection;

The satellite side protocol entity 60 further includes:

The connection maintenance module 605 is configured to: after receiving the notification that the second TCP connection is interrupted, send, by the satellite link, a message requesting to close the connection to the opposite gateway, where the TMSG header carries the first TCP connection identifier After receiving the response message that the connection returned by the peer gateway is successfully closed, the server side protocol entity is notified that the connection is successfully closed.

Optionally,

The connection maintenance module 605 of the satellite side protocol entity 60 is further configured to send a notification that the satellite link is disconnected to the server side protocol entity 50 when detecting that the satellite link is disconnected;

The connection maintenance module 505 of the server side protocol entity 50 is further configured to associate the second TCP connection with the satellite link; after receiving the notification that the satellite link is disconnected, the satellite chain All TCP connections associated with the road are broken.

In the above embodiment, in the dual-ended PEP scenario, the two gateways use TCP spoofing for the server and the client respectively, and implement TCP transmission between the client and the server without modifying the protocol stack of the server and the client. Correlation processing can also reduce the bandwidth occupation by replacing the TCP header with a simpler TMSG header to convert and compress the IP+TCP header.

The method and gateway of the embodiment of the present invention will be described as a whole with an application example.

11 is a diagram showing a client according to the above embodiment, a gateway connected to the client, a gateway connected to the server, and a protocol stack on the server.

The protocol stack on both the client and the server includes TCP, IP, and MAC. Chemical.

On the gateway connected to the client, the protocol stack on the side connected to the client includes: TCP, IP, and MAC, and the physical layer protocol stack is not shown. As described in the first embodiment, the packet filtering module 101 needs to be set in the physical layer, and cooperates with the Socket server 103 in the TCP layer to implement TCP spoofing to the client (that is, when the client communicates with the gateway, it is considered to be The end is the server). The protocol stack on the side of the gateway and the satellite network includes: TMSG and RMAC (Reliable Physical Layer Transport Protocol). The TMSG protocol is used to encapsulate and decapsulate the TMSG header. The RMAC protocol can use multiple satellite-based links. The communication protocol, for example, may be a TCP protocol modified for a satellite link, or a proprietary protocol designed specifically for a satellite network, etc., which is not limited by the embodiment of the present invention.

On the gateway connected to the server, the protocol stack on the side connected to the satellite network includes: TMSG and RMAC. Similarly, the TMSG protocol is used to encapsulate and decapsulate the TMSG header of the message, and the RMAC protocol is a communication protocol based on the satellite link.

The processing steps of connection establishment, data transmission, and connection shutdown of this example are described below. among them:

The establishment process includes:

1) The client initiates a TCP connection request to the server;

2) When the connection request passes through GW1, GW1 intercepts the request message and records the TCP connection information;

3) GW1 performs TCP spoofing on the client, sends a pseudo-answer, and initiates a chain-building request to GW2;

4) After receiving the GW2, record the relevant information, and then establish a TCP connection with the server according to the information contained in the link establishment request sent by GW1, and after the TCP is successfully established, respond to the GW1 with a link establishment success message;

5) The two parties have established a successful connection.

An exemplary processing step comprising:

1) The client initiates a TCP connection request to the server;

2) When the connection request passes through GW1, the GW1 underlying protocol stack packet filtering module 101 intercepts the request packet, and records the TCP connection information, including the source IP address, the source port, the destination IP address, and the destination port.

3) The GW1 packet filtering module 101 replaces the destination IP of the request packet with the IP of the GW1. The port is replaced by 10086, and is sent to the Socket server 103 of the upper layer of the GW1. The Socket server 103 receives the TCP request message, responds to the request, and sends a response message to the client, passing through the GW1 bottom layer, and the packet filtering module 101 records from the port. Find the connection information recorded in the second step in the table. If it can be found, replace the source IP address and source port of the response message with the IP address and port of the server recorded in the table.

4) The client receives the response message and considers that it is sent by the real server, and responds to the third packet in the TCP three-way handshake. When the packet passes through the GW1, the underlying packet capture module is also replaced with the destination IP and destination. The port is sent to the upper Socket server 103 of the GW1. After the TCP connection between the client and the GW1 is established, the Socket ID corresponding to the connection is generated on the GW1, and is used as the connection identifier in the TMSG header.

5) After the TCP Socket is established between the client and GW1, GW1 sends a connection request to GW2, encapsulates the TMSG header, and the message type is to request to establish a connection. The connection identifier fills in the Socket ID (GW1SID) recorded in the fourth step, and the message content. The source IP source port of the client recorded in the second step, and the IP address and port of the server;

6) After receiving the request, GW2 records the source IP address, source port, destination IP address, destination port, and Socket ID carried in the packet, and then establishes a TCP connection to the server. After the TCP three-way handshake is successfully established, a local Socket ID is generated. GW2SID), responding to the GW1 to establish a link success message, encapsulating the TMSG header, the message type is successful, the connection identifier is filled in as GW2SID, and the message content is empty;

7) GW1 receives the message that the connection is successfully established, and records the GW2SID;

8) The two parties have established a successful connection.

The client->server direction data transfer process includes:

1) The client sends data to the server;

2) After receiving the GW1, the GW1 intercepts the data packet, extracts the content to be transmitted, encapsulates the TMSG header, and sends it to the GW2 through the RMAC protocol, and simultaneously performs a pseudo-response to the client;

3) After receiving GW2, the data content is taken out and sent to the server through a TCP link established with the server;

4) After receiving the data, the server forwards it to the application layer for processing.

An exemplary processing step comprising:

1) The client sends the data to the server;

2) After receiving the packet, GW1 receives the TCP data packet sent by the client through the packet filtering module 101, and then checks whether the connection request record exists through the source IP address, the source port, the destination IP address, and the destination port. Discard if it exists. If yes, the destination IP address of the modified TCP data packet is changed to the IP address of GW1, the destination port is modified to 10086, and sent to the upper layer Socket server 103. The GW1 upper layer Socket server 103 responds to the data packet to the underlying packet filtering module. 101. The lookup table replaces the source IP source port and sends it to the client, and the processing step is similar to the connection establishment process;

3) GW1 upper layer Socket server 103 takes out the TCP packet data content, encapsulates the TMSG hair to be sent to GW2, and the message type encapsulation is data transmission, and the identifier connection encapsulation is the GW2SID recorded when the connection is established;

3) After receiving the message, GW2 extracts the data content, searches for the corresponding TCP connection according to the GW2SID in the TSMG header, and forwards the data to the server.

The server->client direction data transfer process includes:

1) The server sends data to the client;

2) After receiving GW2, the data content is taken out, and the TMSG header is encapsulated and sent to GW1 through the RMAC protocol. Since the server is a TCP connection established with GW2, the protocol stack directly sent by GW2 directly sends a response to the server;

3) GW1 receives the RMAC packet sent by GW2, extracts the data, converts it into a TCP packet, and replaces the source IP address and the source port with the source IP address and source port of the server, and sends the source IP address and the source port to the client.

4) The customer receives the data and forwards it to the application layer for processing.

An exemplary processing step comprising:

1) The server sends data to the client;

2) GW2 receives the data sent by the server, extracts the data, encapsulates the TMSG hair and sends it to GW1, and the message type is data transmission, and identifies the GW1SID recorded when the connection is established;

3) After receiving the packet, GW1 takes out the GW1SID, finds the corresponding TCP connection, and sends the packet to the client.

4) The underlying packet filtering module intercepts the packet, and then searches for the table information recorded during the connection establishment process, replacing the source IP with the server IP, and the source port is the server port;

5) After the customer receives the data, it is sent to the upper application.

The process of disconnecting a client includes:

1) GW1 detects a communication interruption of the TCP connection with the client, and sends a disconnection request to GW2;

2) After receiving the GW2, the TCP connection between the server and the server is closed, and the recorded connection related information is cleared, and the shutdown success message is sent to the GW1 after completion;

3) GW1 receives the message, closes the corresponding TCP connection with the client, and clears the relevant information.

An exemplary processing step comprising:

1) GW1 detects a communication interruption with the client's TCP connection:

2) GW1 sends a close connection request to GW2, encapsulates the TMSG header, the message type is closed, the connection identifier is GW2SID, and the message content is empty;

3) After receiving the request, GW2 takes out the GW2SID, closes the TCP connection with the server, and sends a shutdown success message to GW1, encapsulating the TMSG header, and the message type is that the connection is successfully closed;

4) GW1 receives the response message and closes the TCP connection with the client.

The process of disconnecting the server includes:

1) GW2 detects a communication interruption of the TCP connection with the server, and sends a disconnection request to GW1;

2) After receiving the request, GW1 closes the TCP connection with the client, and clears the recorded connection related information, and sends a shutdown success message to GW2 after completion;

3) GW2 receives the message, closes the connection with the server, and clears the relevant information.

An exemplary processing step comprising:

1) GW2 detects that the communication of the TCP connection with the server is interrupted;

2) GW2 sends a close connection request to GW1, encapsulates the TMSG header, the message type is closed, the connection identifier is GW1SID, and the message content is empty;

3) After receiving the request, GW1 takes out the GW1SID, closes the TCP connection with the client, and sends a shutdown success message to GW2, encapsulating the TMSG header, and the message type is that the connection is successfully closed;

4) GW2 receives the response message and disconnects the TCP connection with the server.

The processing after the satellite link is disconnected includes:

1) The underlying RMAC protocol of GW1 detects that the satellite link is disconnected, and closes all TCP connections associated with the satellite link with the client;

2) The underlying RMAC protocol of GW2 detects the disconnection of the satellite link and closes all TCP connections associated with the satellite link with the server.

One of ordinary skill in the art will appreciate that all or a portion of the steps described above can be accomplished by a program that instructs the associated hardware, such as a read-only memory, a magnetic or optical disk, and the like. Optionally, all or part of the steps of the foregoing embodiments may also be implemented by using one or more integrated circuits. Accordingly, each module/unit in the foregoing embodiment may be implemented in the form of hardware, or may be implemented by using a software function module. Formal realization. Embodiments of the invention are not limited to any specific form of combination of hardware and software.

Industrial applicability

Claims

A method for implementing a transmission control protocol TCP transmission in a satellite network environment, characterized in that it is applied to a gateway connected to a client in a double-ended acceleration proxy PEP, and the method includes the following connection establishment processing:

Intercepting a TCP connection request sent by the client to the server, extracting the first connection information therefrom, and sending a pseudo response to the client, establishing a first TCP connection with the client;

And using the first connection information as a data part and encapsulating the conversion message TMSG header, generating a message requesting to establish a connection and sending the message to the opposite gateway connected to the server by using a satellite link, where the TMSG header is carried by the identifier Determining a first TCP connection identifier of the first TCP connection;

After receiving the response message that the connection is successfully established by the peer gateway, the second TCP connection identifier carried in the TMSG header is recorded and associated with the first TCP connection identifier, where the second TCP connection identifier is The identifier of the TCP connection established between the peer gateway and the server.
The method of claim 1 wherein:

The TMSG header includes a message type, a connection identifier, and a message length field, and the TMSG header length is less than a length of the TCP header.
The method of claim 1 or 2, the method further comprising the following processing of data transmission:

Intercepting and responding to the TCP data packet sent by the client to the server through the first TCP connection, extracting a data part from the TCP data packet, and encapsulating the TMSG header, and generating the generated data transmission message through the satellite Sending a link to the peer gateway, the TMSG header carrying the second TCP connection identifier associated with the first TCP connection identifier; and

Receiving a data transmission message from the satellite link, where the connection identifier of the TMSG header is the first TCP connection identifier, extracting a data part from the data transmission message and encapsulating a corresponding TCP header, and generating a TCP A data message is sent to the client over the first TCP connection.
The method of claim 1 or 2, further comprising the following process of disconnection:

A communication interruption of the first TCP connection is detected;

Transmitting, by the satellite link, a packet requesting to close the connection to the peer gateway, where the TMSG header carries the second TCP connection identifier;

After receiving the response message that the connection returned by the peer gateway is successfully closed, the first TCP connection is disconnected.
The method of claim 1 or 2, wherein the process of establishing the connection further comprises associating the first TCP connection with the satellite link;

The method also includes the following process of disconnection: detecting that the satellite link is down, disconnecting all TCP connections associated with the satellite link.
A gateway for connecting to a client in a double-ended acceleration proxy PEP, comprising a user side protocol entity and a first satellite side protocol entity, wherein:

The user side protocol entity includes an underlying packet filtering module and an upper layer socket Socket server;

The packet filtering module includes:

The reverse forwarding unit is configured to intercept the connection request message and the ACK message sent when the client establishes a TCP connection with the server, and replace the destination IP address and the destination port in the packet with the IP address and port of the Socket server. Sending to the Socket server; wherein, when the connection request message is intercepted, the first connection information including the source IP address, the source port, the destination IP address, and the destination port is also recorded and sent to the Socket server;

a forward forwarding unit, configured to replace the source IP address and the source port in the ACK packet sent by the Socket server to the client with the destination IP address and the destination port in the first connection information, and send the The client;

The Socket server includes: a first connection establishing module, configured to: after receiving the connection request message and the first connection information sent by the packet filtering module, send an ACK message to the client; and send the packet filtering module After the ACK message, the first TCP connection with the client is established, and a first TCP connection identifier is generated to notify the first satellite side protocol entity that the first TCP connection is successfully established, and the first connection information is carried. ;

The first satellite side protocol entity includes: a second connection establishing module, configured to: after receiving the notification that the first TCP connection is successfully established by the Socket server, using the first connection information as a data part and encapsulating the conversion message TMSG Header, generating a message requesting to establish a connection and transmitting the message to the opposite gateway through a satellite link, the TMSG header carrying the first TCP connection identifier; and being set to receive After the peer gateway establishes a successful response message through the connection returned by the satellite link, the second TCP connection identifier carried in the TMSG header is recorded and associated with the first TCP connection identifier, and the second TCP connection is Identifying an identifier of a TCP connection established by the peer gateway and the server.
The gateway of claim 6 wherein:

The TMSG header encapsulated by the second connection establishment module of the first satellite side protocol entity includes a message type, a connection identifier, and a message length field, and the TMSG header length is smaller than a length of the TCP header.
A gateway as claimed in claim 6 or claim 7, wherein:

The reverse forwarding unit in the packet filtering module is further configured to intercept the passed TCP data packet. If the connection information matches the first connection information, the TCP data packet is from the first TCP connection, and the TCP data packet is sent from the first TCP connection. The destination IP address and the destination port in the TCP data packet are replaced with the IP address and port of the Socket server, and sent to the Socket server;

The Socket server further includes: a message processing module, configured to receive the TCP data packet from the first TCP connection and send a TCP response message;

The forward forwarding unit in the packet filtering module is further configured to replace the source IP address and the source port in the TCP response message sent by the Socket server to the client with the destination IP in the first connection information. After the address and the destination port are sent to the client;

The first satellite side protocol entity further includes: a first packet sending and receiving module, configured to encapsulate a TMSG header before the data portion of the TCP data packet from the first TCP connection, and the generated data sending message passes the A satellite link is sent to the correspondent gateway, and the TMSG header carries the second TCP connection identifier associated with the first TCP connection identifier.
The gateway of claim 8 wherein:

The first packet transceiver module of the first satellite side protocol entity is further configured to receive a data transmission message sent to the client from the satellite link;

The packet processing module in the Socket server is further configured to identify a data transmission message received by the first satellite side protocol entity, where the connection identifier of the TMSG header is the first TCP connection identifier, then the data is sent from the data. Extracting a data part in the sending message and encapsulating a corresponding TCP header, and the generated TCP data message is sent to the client through the first TCP connection;

The forward forwarding unit in the packet filtering module is further configured to send the Socket server to After the source IP address and the source port in the TCP data packet of the client are replaced with the destination IP address and the destination port in the first connection information, the source IP address and the destination port are sent to the client.
A gateway as claimed in claim 6 or 7 or 9 wherein:

The Socket server further includes: a first connection maintenance module, configured to notify the first satellite side protocol entity that the first TCP connection is interrupted when detecting that the first TCP connection communication is interrupted; and receiving the first satellite After the connection of the side protocol entity is closed successfully, the first TCP connection is disconnected;

The first satellite side protocol entity further includes: a second connection maintenance module, configured to send a request to the peer gateway to close by using the satellite link after receiving the notification that the first TCP connection is interrupted by the Socket server The connected message, wherein the TMSG header carries the second TCP connection identifier; and is configured to notify the Socket server that the connection is successfully closed after receiving the response message that the connection returned by the opposite gateway is successfully closed.
The gateway of claim 10 wherein:

The second connection maintenance module of the first satellite side protocol entity is further configured to send a notification that the satellite link is disconnected to the Socket server when detecting that the satellite link is disconnected;

The first connection maintenance module of the Socket server is further configured to associate the first TCP connection with the satellite link; after receiving the notification that the satellite link is disconnected, the node is associated with the satellite link All TCP connections are broken.
A method for implementing TCP transmission in a satellite network environment, characterized in that it is applied to a gateway connected to a server in a double-end acceleration proxy PEP, and the method includes the following connection establishment processing:

After receiving the packet of the connection establishment request sent by the peer gateway connected to the client via the satellite link, recording the first TCP connection identifier carried by the switching message TMSG header and the client carried by the data part and the pair The first connection information of the first TCP connection established by the end gateway, where the first TCP connection identifier is used to identify the first TCP connection;

Establishing a second TCP connection with the server, and after the connection is established, returning a connection establishment success message to the opposite gateway through the satellite link, where the TMSG header carries the identifier for identifying the second TCP connection. a second TCP connection identifier; associating the second TCP connection identifier with the first TCP connection identifier.
The method of claim 12 wherein:

The TMSG header includes a message type, a connection identifier, and a message length field, and the TMSG header length is less than a length of the TCP header.
The method of claim 11 or 12, the method further comprising the following processing of data transmission:

Receiving, by the server, the TCP data packet sent to the client by using the second TCP connection, responding, extracting the data part from the TCP data packet, and encapsulating the TMSG header, generating a data transmission packet and passing the packet Sending the satellite link to the peer gateway, the TMSG header carrying the first TCP connection identifier associated with the second TCP connection identifier; and

Receiving, by the satellite link, a data transmission message sent to the server, where the connection identifier carried by the TMSG header is the second TCP connection identifier, extracting a data part from the data transmission message and encapsulating The corresponding TCP header, the generated TCP data message is sent to the server through the second TCP connection.
The method according to claim 11 or 12, further comprising the following process of disconnection:

A communication interruption of the second TCP connection is detected;

Transmitting, by the satellite link, a packet requesting to close the connection to the peer gateway, where the TMSG header carries the first TCP connection identifier;

After receiving the response message that the peer gateway returns a successful connection returned by the satellite link, the second TCP connection is disconnected.
The method of claim 11 or 12, wherein the process of establishing the connection further comprises associating the second TCP connection with the satellite link;

The method also includes the following process of disconnection: detecting that all of the TCP connections associated with the satellite link are disconnected after the satellite link is disconnected.
A gateway for connecting to a server in a double-ended acceleration proxy PEP, comprising a server side protocol entity and a second satellite side protocol entity, wherein:

The second satellite side protocol entity includes: a third connection establishing module, configured to receive the message of the connection establishment request sent by the peer gateway connected to the client via the satellite link, and record the transfer Transmitting the first TCP connection identifier carried by the TMSG header and the first connection information carried in the data part, and notifying the server side protocol entity to establish a second TCP connection with the server; the first connection information is the peer gateway Connection information of the first TCP connection established with the client, the first TCP connection identifier is used to identify the first TCP connection;

The server-side protocol entity includes: a fourth connection establishing module, configured to establish the second TCP connection with the server after receiving the notification of establishing the TCP connection, and generate a second TCP connection for identifying the second TCP connection And the second TCP connection identifier, the response message that the connection establishment is successful is returned to the opposite gateway by the satellite link, the second TCP connection identifier is carried, and the second satellite side protocol entity is notified of the second TCP connection. Successfully established, carrying the second TCP connection identifier;

The third connection establishing module of the second satellite side protocol entity is further configured to: after receiving the notification that the second TCP connection is successfully established by the server side protocol entity, returning the connection establishment to the peer gateway by using the satellite link a successful response message, wherein the TMSG header carries the second TCP connection identifier; and the second TCP connection identifier is associated with the first TCP connection identifier.
The gateway of claim 17 wherein:

The server-side protocol entity further includes: a second packet transceiver module, configured to receive a TCP data packet sent by the server to the client through the second TCP connection, and respond;

The second satellite side protocol entity further includes: a third packet sending and receiving module, configured to extract a data part from the TCP data packet received by the server side protocol entity, and encapsulate a TMSG header, and generate a data sending message. And transmitting, by the satellite link, the peer gateway, where the TMSG header carries the first TCP connection identifier associated with the second TCP connection identifier.
The gateway of claim 18 wherein:

The third packet transceiver module of the second satellite side protocol entity is further configured to receive a data transmission message sent to the server from the satellite link;

The second packet sending and receiving module of the server side protocol entity is further configured to identify a data sending message received by the second satellite side protocol entity, where the connection identifier carried by the TMSG head is the second TCP connection identifier. And extracting a data part from the data sending message and encapsulating a corresponding TCP header, and the generated TCP data message is sent to the server by using the second TCP connection.
A gateway as claimed in claim 18 or 19, wherein:

The TMSG header encapsulated by the third packet transceiver module of the second satellite side protocol entity includes a message type, a connection identifier, and a message length field, and the TMSG header length is smaller than a length of the TCP header.
A gateway as claimed in claim 17 or 18 or 19, wherein:

The server-side protocol entity further includes: a third connection maintenance module, configured to notify the second satellite-side protocol entity that the second TCP connection is interrupted when detecting that the communication of the second TCP connection is interrupted; and receiving the After the connection of the second satellite side protocol entity is successfully closed, disconnecting the second TCP connection;

The second satellite side protocol entity further includes: a fourth connection maintenance module, configured to send a message requesting to close the connection to the opposite gateway through the satellite link after receiving the notification that the second TCP connection is interrupted, The TMSG header carries the first TCP connection identifier; and after receiving the response message that the connection returned by the peer gateway is successfully closed, the server side protocol entity is notified that the connection is successfully closed.
The gateway of claim 21 wherein:

The fourth connection maintenance module of the second satellite side protocol entity is further configured to: when detecting that the satellite link is disconnected, send a notification that the satellite link is disconnected to the server side protocol entity;

The third connection maintenance module of the server side protocol entity is further configured to associate the second TCP connection with the satellite link; and after receiving the notification that the satellite link is disconnected, the satellite chain All TCP connections associated with the road are broken.