CN112118183A - Message forwarding method - Google Patents
Message forwarding method Download PDFInfo
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- CN112118183A CN112118183A CN201910518274.2A CN201910518274A CN112118183A CN 112118183 A CN112118183 A CN 112118183A CN 201910518274 A CN201910518274 A CN 201910518274A CN 112118183 A CN112118183 A CN 112118183A
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- Prior art keywords
- message
- port
- server
- proxy server
- service server
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L45/00—Routing or path finding of packets in data switching networks
- H04L45/74—Address processing for routing
- H04L45/745—Address table lookup; Address filtering
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L45/00—Routing or path finding of packets in data switching networks
- H04L45/74—Address processing for routing
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
- H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
- H04L1/1607—Details of the supervisory signal
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
- H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
- H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
- H04L1/1806—Go-back-N protocols
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L61/00—Network arrangements, protocols or services for addressing or naming
- H04L61/09—Mapping addresses
- H04L61/25—Mapping addresses of the same type
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L67/00—Network arrangements or protocols for supporting network services or applications
- H04L67/14—Session management
- H04L67/141—Setup of application sessions
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L67/00—Network arrangements or protocols for supporting network services or applications
- H04L67/50—Network services
- H04L67/56—Provisioning of proxy services
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L67/00—Network arrangements or protocols for supporting network services or applications
- H04L67/50—Network services
- H04L67/56—Provisioning of proxy services
- H04L67/568—Storing data temporarily at an intermediate stage, e.g. caching
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
- H04L69/16—Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Data Exchanges In Wide-Area Networks (AREA)
Abstract
The invention provides a message forwarding method, which is applied to a communication system comprising a client, a proxy server and a service server, wherein a forwarding channel T is arranged between the service server and the proxy server, a port P0 and a port P1 are respectively monitoring ports of the service server and the proxy server, the service server establishes a mapping relation from P0 to (P1, T), the proxy server establishes a mapping relation from P1 to (P0, T), the proxy server sends a message D2 through the forwarding channel T after receiving a message D1 at a port P1, and the message D2 contains source address information of the message D1; and after receiving the message D2, the server constructs a message D3, wherein the source address of the message D3 is the source address of the message D1, and the destination port is P0. By the method, resources of the proxy server and the service server can be saved, and transmission reliability between the client and the service server is improved.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a packet forwarding method.
Background
Fig. 1 is a schematic diagram of a Network topology according to the present invention, in which a service server accesses the internet through a Network Address Translation (NAT) router, and due to the NAT technology, a client and other devices on the internet cannot directly access the service server. Fig. 2 depicts a specific flow of the prior art, and the following is described in detail by taking a TCP (Transmission Control Protocol) port P1 of a client accessing a proxy server as an example:
201. the service server is used as a client to establish a TCP connection T to the proxy server, and sends a message to request the proxy server to distribute a TCP port corresponding to a TCP port P0 through the connection T;
202. the proxy server distributes a port P1 and establishes a mapping relation between P1 and (P0, T);
203A, client and proxy port P1 establish TCP connection C0;
203B, TCP sending service data through the connection after the connection is successfully established, wherein the service data refers to the data part in the TCP protocol;
203C, caching service data by the proxy server;
204. the proxy server searches the mapping relation according to P0, and sends a message to the service server through the connection T to inform that a newly established TCP connection exists on the port P0, wherein the message comprises the value of the port P1 and the identifier of the TCP connection C0;
205. the service server and the local TCP port P1 establish a local connection C1 and establish a mapping relation between C1 and C0;
206. after C1 is successfully established, the service server sends a message to inform the proxy server that the data received on the connection C0 can be forwarded, wherein the message contains the identifications of C0 and C1;
207. the proxy server establishes a mapping relation between C0 and C1, and sends a message through T, wherein the message comprises the identifier of C1 and the service data cached in the step 203C;
208. the service server sends the service data through the connection C0 according to the C1 identifier in the message.
The prior art has the following disadvantages:
1. the occupied resources are more: if a plurality of clients need to access the service server, the proxy server and each client need to establish TCP connection, and the service server also needs to establish the same number of local TCP connections to occupy a plurality of TCP resources; moreover, a local TCP connection of the service server needs to occupy one TCP port, which is also a limited resource;
2. unreliable message transmission: in order to realize reliable transmission, the TCP protocol requires sending an ACK message after receiving the message, and if the transmitting and receiving end does not receive the ACK message, the message needs to be retransmitted. In the above flow, step 203C defaults to send an ACK message when receiving a message, and if a transmission failure (e.g., connection T interruption) occurs in a subsequent step, a service message sent by the client is actually lost, but the client cannot sense the loss of the message and no retransmission occurs, thereby causing unreliable transmission between the client and the service server.
Disclosure of Invention
The embodiment of the invention provides a message forwarding method, which can save resources of a proxy server and a service server and simultaneously improve the transmission reliability between a client and the service server.
In view of this, the embodiment of the present invention provides:
a message forwarding method is applied to a communication system comprising a client, a proxy server and a service server, wherein a forwarding channel T is arranged between the service server and the proxy server, a port P0 and a port P1 are respectively monitoring ports of the service server and the proxy server, the service server establishes a mapping relation from P0 to (P1, T), the proxy server establishes a mapping relation from P1 to (P0, T), the proxy server sends a message D2 through the forwarding channel T after receiving a message D1 at a port P1, and the message D2 comprises source address information of the message D1 and port P0 information; and after receiving the message D2, the service server constructs a message D3, wherein the source address of the message D3 is the source address of the message D1, and the destination port is P0.
The invention has the beneficial effects that: the resources of the proxy server and the service server are saved, and the transmission reliability between the client and the service server is improved.
Drawings
FIG. 1 is a schematic diagram of the network topology of the present invention;
FIG. 2 is a prior art flow diagram;
FIG. 3 is a flow chart of an embodiment of the present invention;
fig. 4 is a schematic diagram of packet encapsulation according to an embodiment of the present invention.
Detailed Description
The invention is primarily applicable to the network topology shown in fig. 1; because of the characteristics of the NAT technology, whether NAT equipment exists in the network has no influence on the technical scheme of the invention, and in order to highlight the technical scheme, the NAT equipment is not embodied in the embodiment of the invention.
Referring to fig. 3, an embodiment of the present invention provides a packet forwarding method, which is applied to a communication system including a client, a proxy server, and a service server, where a forwarding channel T is located between the service server and the proxy server, a port P0 and a port P1 are listening ports of the service server and the proxy server, the service server has established a mapping relationship from P0 to (P1, T), and the proxy server has established a mapping relationship from P1 to (P0, T); the message forwarding process among the client, the proxy server and the service server is as follows:
301. the client sends a message D1 to a port P1 of the proxy server;
302. the proxy server searches a mapping relation table according to the port P1 to determine a channel T and a port P0, and then sends a message D2 through the T, wherein the message D2 comprises port P0 information, source address information of the message D1 and application data;
303. the service server constructs a message D3 according to the information in the message D2, wherein the source address of the message D3 is the source address of the message D1, and the destination port is P0;
304. if the service server needs to send a message to the client by using the port P0, searching a mapping relation according to P0 to determine a channel T and a port P1; then sending a message D4 through T, wherein the message D4 contains port P1 information and source address information of the message D1;
305. the proxy server constructs a message D5 according to the information in the message D4, wherein the source port of the message D5 is P1, and the destination address is the source address of the client.
For more clearly describing the message forwarding method, it is assumed that:
1. the IP address of the service server is 11.1.1.1, and the port P0 is a TCP port 3389; the proxy server IP address is 22.2.2.2, port P1 is TCP port 9833;
2. the IP addresses of the forwarding channel T are respectively 11.1.1.1:1000 and 22.2.2.2:2000 in port number, and the protocol is UDP;
3. the client has an IP address of 33.3.3.3 and communicates with a proxy server 9833 port using a TCP source port 3000.
The message encapsulation in the above flow is as shown in fig. 4 (the message only shows the key content of the IP message):
message D1: in the standard TCP message, the source address is the IP address of the client and the used port number, and the destination address is the IP address of the proxy server and P1;
message D2: modifying the destination IP and the destination port of D1 into the IP address of the service server and P0, and then using the IP address and the P0 as the application data of UDP;
message D3: taking out an application data part of the UDP message as an IP message;
message D4: the application data of the UDP is a standard TCP message, but the TCP message uses the IP address of the proxy server and P1 as the source address;
message D5: and taking out the application data part of the UDP message as the IP message.
After the TCP connection is established, a TCP connection is newly generated on the client side, the local address and the remote address are 33.3.3.3:3000 and 22.2.2.2:9833, the TCP connection is not newly generated on the proxy server, a connection is newly generated on the service server, and the local address and the remote address are 11.1.1.1:3389 and 33.3.3.3: 3000.
The method for the message D2 to carry the source address of D1 and the port P0 information is not limited to that shown in fig. 4, and if the message D1 is directly used as the application data of the message D2, since the service server has the mapping relationship from P0 to (T, P1), the port P0 can be determined on the service server through T and P1; similar methods are not exhaustive, but should be considered within the scope of the present invention.
The above description of the embodiments is only for the purpose of helping understanding the method of the present invention and the core idea thereof, and for those skilled in the art, the specific implementation and the application range may be changed according to the idea of the present invention; in view of the above, the present disclosure should not be construed as limiting the invention.
Claims (3)
1. A message forwarding method is applied to a communication system comprising a client, a proxy server and a service server, wherein a forwarding channel T is arranged between the service server and the proxy server, a port P0 and a port P1 are respectively monitoring ports of the service server and the proxy server, the service server establishes a P0-to-T mapping relation, and the proxy server establishes a P1-to-T mapping relation, and is characterized by comprising the following steps:
the proxy server sends a message D2 through the forwarding channel T after receiving the message D1 at the port P1, wherein the message D2 contains source address information of the message D1 and information of the port P0;
and after receiving the message D2, the server constructs a message D3, wherein the source address of the message D3 is the source address of the message D1, and the destination port is the P0.
2. The method of claim 1, the traffic server accessing the internet through a NAT device.
3. The method according to claim 1, wherein the message D1 is a TCP message.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910518274.2A CN112118183A (en) | 2019-06-19 | 2019-06-19 | Message forwarding method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910518274.2A CN112118183A (en) | 2019-06-19 | 2019-06-19 | Message forwarding method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112118183A true CN112118183A (en) | 2020-12-22 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910518274.2A Pending CN112118183A (en) | 2019-06-19 | 2019-06-19 | Message forwarding method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112118183A (en) |
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2019
- 2019-06-19 CN CN201910518274.2A patent/CN112118183A/en active Pending
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