CN109714258B - VDES packet data gateway and implementation method thereof - Google Patents

Abstract

The invention provides a packet data gateway based on VDES and a realization method thereof, which relate to the technical field of communication and comprise the following steps: establishing a packet data transmission channel between a source station and a destination station through a shore station, a VDESSN module, a VDEGSN module or an external network; exchanging the plurality of data formats between the source station and the destination station through the packet data transmission channel. The invention designs a VDES packet data gateway, which realizes and expands the data exchange function of VDES.

Description

VDES packet data gateway and implementation method thereof

Technical Field

The invention relates to the technical field of communication, in particular to a VDES packet data gateway and an implementation method thereof.

Background

An Automatic Identification System (AIS) for ships is a ship and shore-based broadcasting System working in a Very High Frequency (VHF) offshore Frequency band, and is a navigation aid System or an offshore safety System integrating modern communication, network technology and information technology. The AIS adopts SOTDMA multiple access communication, and transmits navigation information to peripheral ships and onshore base station facilities so as to reduce the probability of collision between the ships to the maximum extent and ensure the safety of the ships in the sea. With the rapid spread of AIS, the limitations of AIS gradually emerge: on one hand, extended applications such as navigation marks, hydrology and weather are continuously increased, the AIS has serious insufficient data exchange capacity, and high data link loads occur in some busy areas; on the other hand, early AIS mainly includes VHF of a land-based base station, and the coverage range is only about 30 nautical miles, so that global coverage cannot be achieved. In order to improve Data processing capacity and extend communication transmission distance, the ITU world radio communication council (WRC-15) in 11 months of 2015 consults and decides to introduce a very high frequency Data Exchange System (VDES) to further promote the development of the digital communication industry of the marine radio. VDES is a new-generation digital communication System developed for an Automatic Identification System (AIS) of a ship in the field of marine mobile services.

The VDES is an upgrade to AIS, and uses satellite communication as a long-distance information transmission mode, and the main purpose of the VDES is to provide stronger data exchange capability for ship users and widen data application service while realizing maritime affair VHF mobile wave band communication in the global range. The VDES integrates existing functions such as AIS, ASM data exchange (ASM exchange), electronic Navigation (e-Navigation), Enhanced Maritime Communication (EMC), and Global Maritime Distress and Safety System (GMDSS) modernization (modified GMDSS). Briefly, VDES will integrate AIS, Application Specific Messaging (ASM), and wideband very high frequency Data Exchange (VDE) functions.

Under the VDES architecture, AIS keeps its original design purpose unchanged, and is only used for ship identification, position reporting, navigation data, searching and rescue; the ASM is a real-time and reliable information receiving mechanism, and mainly removes other non-navigation safety information except ship position and navigation state information which have the closest relation with navigation safety, wherein the non-navigation safety information comprises information such as hydrology, weather and the like; the VDE is the core function of the VDEs, and is the basis for the VDEs to implement high-bandwidth data communication, and is divided into a ground-based VDE and a space-based (satellite) VDE.

VDES development programs by International Maritime Organization (IMO), international association of beacons (IALA), and International Telecommunications Union (ITU): in 2013-2014, the principle prototype development of the very high frequency data exchange transmitter is developed; in 2015-2017, related drafts are developed and related international standards of VDES are formulated, practical application of a very high frequency data exchange transmitter is promoted, related technologies are researched, and a test satellite is evaluated and transmitted; in 2017-2019, satellite VDES service is developed; in 2020, the full operation capability of VDES is realized. At present, the research and development of VDES systems and related products are actively carried out in all countries, and the research and development of VDES packet data gateway technology are also important.

Therefore, a VDES packet data gateway needs to be designed to implement and extend the data exchange function of VDES.

Disclosure of Invention

The invention provides a VDES packet data gateway and an implementation method thereof, which are used for designing the VDES packet data gateway by combining the specific requirements of a data exchange scene, and realizing and expanding the data exchange function of VDES.

In order to achieve the purpose, the invention adopts the following technical scheme.

One aspect of the present invention provides a method for implementing a packet data gateway based on VDES, including:

establishing a packet data transmission channel between a source station and a destination station through a shore station, a VDESSN module, a VDEGSN module or an external network;

exchanging the plurality of data formats between the source station and the destination station through the packet data transmission channel.

Preferably, the process of exchanging the plurality of data formats of the source station and the destination station further comprises encrypting/decrypting and decompressing/compressing the transmitted data.

Preferably, the source station or the destination station is a ship station, a shore station, a gateway, a network manager, an Internet server authorized in HLR/AUC, or a device in a heterogeneous network, and one of the source station or the destination station is a VDES device.

Preferably, the establishing of the packet data transmission channel between the source station and the destination station through the shore station, the VDESSN module, the VDEGSN module or the external network comprises: establishing a packet data transmission channel in an outbound direction between a source station and a destination station through a shore station, a VDESSN module, a VDEGSN module, or an external network, comprising:

1) after receiving data from a shore, the VDESSN module accesses the HLR/AUC module and performs security authentication and routing by combining the ODID;

2) the VDESSN module directly delivers the data to a VDE-protocol module of a shore platform currently visited by a user according to a routing selection result, or forwards the data to an intra-domain VDESSN module through a Gd interface, or forwards the data to a VDEGSN module through a Gn interface or a Gd interface;

3) after receiving the data from the VDESSN module, the VDEGSN module accesses the HLR/AUC module and the NAT table, and performs security authentication and routing by combining the ODID;

4) the VDEGSN forwards the data to a remote VDEGSN module or an Internet server or other devices in a heterogeneous network according to the routing result.

Preferably, the establishing of the packet data transmission channel between the source station and the destination station through the shore station, the VDESSN module, the VDEGSN module or the external network comprises: establishing a packet data transmission channel in an inbound direction between a source station and a destination station via a land platform, a VDESSN module, a VDEGSN module, or an external network, comprising:

1) after receiving data from an external network, the VDEGSN module accesses the HLR/AUC module and the NAT table, and performs security authentication and routing by combining the ODID;

2) the VDEGSN module directly delivers the data to the current VDEGSN according to the routing result, or forwards the data to the intra-domain VDESSN module through a Gn interface or a Gd interface;

3) after receiving the data from the VDEGSN module, the VDESSN module accesses the HLR/AUC module and performs security authentication and routing by combining the ODID;

4) and the VDESSN module forwards the data to the current VDE-protocol module or the current VDESSN module according to the routing result.

Preferably, the process of exchanging the plurality of data formats of the source station and the destination station further comprises encrypting/decrypting and decompressing/compressing the transmitted data, including:

the compression process of private IP packets from inside the VDES network all occurs at the source VDES station; the compression process of the IP packet from the Internet occurs in the VDESSN module, and a Multi-protocol Header needs to be added to the compressed IP packet for encapsulation, and the decompression process occurs in a destination VDES platform;

the Multi-protocol Header carries data types, encryption options, compression options and custom option parameters.

The invention provides a VDES-based packet data gateway on the other hand, which comprises a VDE-Block module, a packet data state machine, an environment model, a VDESSN module, a VDEGSN module and an HLR/AUC module;

the VDE-Block module is used for realizing Az interface primitive message processing between a transmission layer and a network layer, PDU packaging and unpacking format processing and protocol internal parameter processing;

the packet data state machine is used for receiving related parameters of data transmission and skipping the state according to the received parameters;

the environment model is used for realizing generation, transmission and conversion of communication signals between the VDE-Block module and the VDESSN module;

the VDESSN module is used for intra-domain routing, packet forwarding, authentication, encryption/decryption, decompression/compression and GTP session management;

the VDEGSN module is used for routing and packet forwarding outside a domain, protocol conversion, data filtering, NAT and dynamic IP allocation;

the HLR/AUC module is used for storing the information of the platform and realizing the authority access and addressing positioning of the maritime platform, the gateway and the specific network.

Preferably, the VDESSN module is configured to forward the data to the VDEGSN module through a Gn interface (GTP protocol) or a Gd interface;

the VDEGSN module is used for forwarding data to the VDESSN module in the domain through a Gn interface or a Gd interface.

Preferably, the VDEGSN module further includes a Muliti-protocol sub-module for performing format conversion on the received or output data.

It can be seen from the above technical solutions provided by the VDES packet data gateway and the implementation method thereof of the present invention that the VDES packet data gateway obtained by analyzing the latest VDES standard based on the hardware platform of the existing server and combining the specific requirements of the data exchange scenario can efficiently and flexibly implement VDE functions such as multiple data format exchange, data compression, data encryption, and interworking with heterogeneous networks between the marine platforms; the gateway expands the presentation layer in the VDES protocol, and introduces double interfaces between the VDESSN and the VDEGSN, thereby breaking the limit that IP packets are terminated at the VDES gateway.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic diagram illustrating an implementation method of a VDES-based packet data gateway according to a first embodiment;

fig. 2 is a schematic flowchart illustrating an operation of data exchange between stations of the VDES-based packet data gateway according to an embodiment;

fig. 3 is a schematic diagram illustrating a flow of a packet data transmission channel in an outbound direction between a source station and a destination station established by a land platform, a VDESSN module, a VDEGSN module, or an external network of the VDES-based packet data gateway according to an embodiment;

fig. 4 is a schematic flow chart of a packet data transmission channel in an inbound direction between a source station and a destination station established by a land platform, a VDESSN module, a VDEGSN module or an external network of the VDES-based packet data gateway according to an embodiment;

fig. 5 is a schematic diagram of a VDES packet data switching domain protocol stack according to the second embodiment;

fig. 6 is a schematic structural diagram of a VDES-based packet data gateway according to the second embodiment.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

For the convenience of understanding the embodiments of the present invention, the following description will be further explained by taking several specific embodiments as examples in conjunction with the drawings, and the embodiments are not to be construed as limiting the embodiments of the present invention.

Example one

Fig. 1 is a schematic diagram of an implementation method of a packet data gateway based on VDES according to this embodiment, and referring to fig. 1, the method includes:

s1 establishing packet data transmission channel between source station and destination station through bank station, VDESSN module, VDEGSN module or external network;

s2 exchanges data formats of the source station and the destination station through the packet data transmission path.

Further, the process of exchanging the data formats of the source station and the destination station further includes encrypting/decrypting and decompressing/compressing the transmitted data.

When a maritime station (referred to as a source station in this embodiment) initiates data traffic to another maritime station (referred to as a destination station in this embodiment) in the system, a packet data transmission channel between the source station and the destination station needs to be established first. Preferably, the source station or the destination station is a ship station, a shore station, a gateway, a network manager, an Internet server authorized in HLR/AUC, or a device in a heterogeneous network, and one of the source station or the destination station is a VDES device.

Fig. 2 is a schematic diagram of the operation flow of data exchange between stations of the VDES-based packet data gateway, referring to fig. 2, including:

11) the VDE-Block module receives a data transmission request from a shore station or a VDESSN module;

12) completing protocol parameter processing and requesting resource to the system, and jumping to a standby state from an idle state by a packet data state machine;

13) after the parameter check is passed and the resource is successfully applied, the state machine jumps from the standby state to the ready state;

14) after data transmission is finished, closing the current session, and jumping to a standby state from a ready state by the state machine;

15) after no new session exists in a period of time, the system resources are released, and the state machine jumps from the standby state to the idle state.

Fig. 3 is a schematic flow chart of a packet data transmission channel of a VDES-based packet data gateway establishing an outbound direction between a source station and a destination station through a land platform, a VDESSN module, a VDEGSN module, or an external network, and with reference to fig. 3, the method specifically includes:

21) after receiving data from a shore, the VDESSN module accesses the HLR/AUC module through a Gc interface, and performs security authentication and routing by combining with the ODID;

22) the VDESSN module directly delivers the data to a VDE-protocol module of a shore platform currently visited by a user according to a routing selection result, or forwards the data to an intra-domain VDESSN module through a Gd interface, or forwards the data to a VDEGSN module through a Gn interface (GTP protocol) or a Gd interface;

23) after receiving the data from the VDESSN module, the VDEGSN module accesses the HLR/AUC module and the NAT table through the Gc interface, and performs security authentication and routing by combining with the ODID;

24) according to the routing result, the VDEGSN forwards the data to a remote VDEGSN module or an Internet server through a Gi interface by using an NAT technology, or forwards the data to other equipment in a heterogeneous network through a Gp interface through protocol conversion.

The difference between the Gn interface and the Gd interface is the different way of transmitting data:

1) the Gn interface transmits Data according to a GTP Protocol (GPRS tunneling Protocol), and the Data transmission is carried out according to the steps specified by the GTP Protocol during transmission, and the Data transmission, the PDP context activation and the PDP context deactivation are sequentially carried out;

2) the Gd interface utilizes a TCP/IP protocol to transmit data, and the data can be directly transmitted as long as the interface is in a keep-alive state.

Fig. 4 is a schematic flow chart of a packet data transmission channel in an inbound direction between a source station and a destination station established by a land platform, a VDESSN module, a VDEGSN module or an external network of a VDES-based packet data gateway, and referring to fig. 4, the method specifically includes:

31) after receiving data from an external network from a Gi interface or a Gp interface, the VDEGSN module analyzes (a source address and a source port), accesses the HLR/AUC module and the NAT table through the Gc interface, and performs security authentication and routing by combining with the ODID;

32) the VDEGSN module directly delivers the data to the current VDEGSN according to the routing result, or forwards the data to the intra-domain VDESSN module through a Gn interface (GTP protocol) or a Gd interface;

33) after receiving the data from the VDEGSN module, the VDESSN module accesses the HLR/AUC module through a Gc interface and performs security authentication and routing by combining with the ODID;

34) and the VDESSN module forwards the data to the current VDE-protocol module or the current VDESSN module according to the routing result.

Further, performing the process of exchanging the plurality of data formats between the source station and the destination station further includes encrypting/decrypting and decompressing/compressing the transmitted data, including:

the compression process of private IP packets from inside the VDES network all occurs at the source VDES station; the compression process of the IP packet from Internet occurs in the vdesn module, and Multi-protocol Header needs to be added to the compressed IP packet for encapsulation, and the decompression process occurs in the destination VDES station.

The method specifically comprises the following steps:

1) the destination platform strips the Multi-protocol Header from the L4 layer, decompresses or decrypts the data, and finally delivers the presentation layer; it should be noted that, if the destination station is not a VDES device and the transmitted data format is IP packet, it needs to strip the Multi-protocol Header at the vdesn module, decompress or decrypt the IP packet, and finally transmit the IP packet through the Gn interface;

2) the source station encrypts or compresses data from the presentation layer, adds a Multi-protocol Header for packaging, and finally sends the data to an L4 layer; particularly, if the source station is not a VDES device and the transmitted data format is an IP packet, the encryption or compression process for the IP packet occurs in the vdesn module, and a Multi-protocol Header needs to be added to the encrypted or compressed IP packet for encapsulation, and finally the packet is handed to the environment model;

the Multi-protocol Header carries data types, encryption options, compression options and user-defined option parameters, so that consistency of key parameters such as end-to-end data formats, encryption and compression is guaranteed.

Example two

Fig. 6 is a schematic diagram of a packet data Gateway structure based on the VDES according to this embodiment, and referring to fig. 6, the Gateway includes a VDE-Block module, a packet data state machine, an environment model, a vdesn (VDE Service Support Node) module, a VDEGSN (VDE Gateway Support Node) module, and an HLR/AUC module.

The VDE-Block module is used for realizing Az interface primitive message processing between a VDE layer (a transport layer) and an L3 layer (a network layer), PDU packaging and unpacking format processing and protocol internal parameter processing;

the packet data state machine is used for receiving related parameters of data transmission and skipping the state according to the received parameters;

the environment model is used for realizing generation, transmission and conversion of communication signals between the VDE-Block module and the VDESSN module;

the VDESSN module is used for intra-domain routing and packet forwarding, authentication, encryption/decryption, decompression/compression and GTP session management;

the VDEGSN module is used for routing and packet forwarding outside a domain, protocol conversion, data filtering, NAT and dynamic IP allocation;

and the HLR/AUC module is used for storing the information of the platform and realizing the authority access and addressing positioning of the maritime platform, the gateway and the specific network.

Specifically, the packet data state machine includes three parts: a state machine management class, a state machine execution class, and a specific state class.

Preferably, the gateway further comprises a Log module, configured to collect all execution records and state information in the running process of the VDES packet data gateway, so that the VDES packet data gateway can be analyzed by the monitoring device;

further, the VDE-Block module comprises a VDE-format submodule and a VDE-Protocol submodule;

the VDE-format submodule is used for realizing Az interface primitive message processing between a VDE layer and an L3 layer and PDU packaging and unpacking format processing;

and the VDE-Protocol submodule is used for realizing the processing of the internal parameters of the Protocol.

Specifically, fig. 5 is a schematic diagram of a VDES packet data switching domain Protocol stack in this embodiment, where positions of a VDE layer and an L3 layer in the VDES packet switching domain Protocol stack are as shown in fig. 5, the L3 layer first adds a VDE Header to received data only including a Multi-Protocol Header, then sends the VDE Header to a VDE-format submodule through an Az interface, and finally delivers the VDE-Protocol submodule to complete Protocol internal parameter processing and change of a packet data state machine; after receiving data from an environment model, the VDE-Protocol submodule firstly completes Protocol internal parameter processing and change of a packet data state machine, then delivers the data to the VDE-format submodule, and finally sends the data to an L3 layer through an Az interface; the VDE Header is Header information of the VDE layer, and carries parameters such as an Original Source ID (OSID), an Original Destination ID (ODID), and a data length, and the information does not need to be transmitted through an air interface; the Multi-protocol Header is Header information of a Multi-protocol layer, which needs to be transmitted over an air interface.

The Multi-protocol Header carries parameters such as data types, encryption options, compression options, custom options and the like, and expands the data exchange function of the VDES, so that the exchange of a plurality of public protocol or private protocol data formats is supported between the marine platforms; end-to-end data encryption and data compression are supported between the maritime platforms; the maritime stations are capable of interworking with the Internet or other heterogeneous networks; the interworking based on IP packet can be realized inside the maritime platform.

Preferably, the VDESSN module is configured to forward the data to the VDEGSN module through a Gn interface (GTP protocol) or a Gd interface;

and the VDEGSN module is used for forwarding the data to the intra-domain VDESSN module through the Gn interface or the Gd interface.

The VDEGSN module further includes a Muliti-protocol sub-module for performing format conversion on the received or output data.

The specific process of using the apparatus of the embodiment of the present invention to perform resource management in the multimedia communication system is similar to the method embodiment described above, and is not described herein again.

To sum up, the embodiments of the present invention deploy the packet data Gateway in the server, and perform function expansion as little as possible or as little as possible on the basis of the existing database, device addressing, and network planning to complete the data exchange function of the VDES, specifically, establish a packet data transmission channel with the destination station through the shore, the VDESSN (VDE Service Support Node), the VDEGSN (VDE Gateway Support Node), or the external network; various data formats are exchanged with the destination station through the packet data transmission channel, and the transmitted data may be encrypted and compressed.

Those of ordinary skill in the art will understand that: the figures are merely schematic representations of one embodiment, and the blocks or flow diagrams in the figures are not necessarily required to practice the present invention.

From the above description of the embodiments, it is clear to those skilled in the art that the present invention can be implemented by software plus necessary general hardware platform. Based on such understanding, the technical solutions of the present invention may be embodied in the form of a software product, which may be stored in a storage medium, such as ROM/RAM, magnetic disk, optical disk, etc., and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method according to the embodiments or some parts of the embodiments.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for apparatus or system embodiments, since they are substantially similar to method embodiments, they are described in relative terms, as long as they are described in partial descriptions of method embodiments. The above-described embodiments of the apparatus and system are merely illustrative, and the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (8)

1. A method for implementing a packet data gateway based on VDES is characterized by comprising the following steps:

establishing a packet data transmission channel between a source station and a destination station through a shore station, a VDESSN module, a VDEGSN module, or an external network, comprising: establishing a packet data transmission channel in an outbound direction between a source station and a destination station through a shore station, a VDESSN module, a VDEGSN module, or an external network, comprising:

41) after receiving data from a shore, the VDESSN module accesses the HLR/AUC module and performs security authentication and routing by combining the original destination identifier ODID;

42) the VDESSN module directly delivers the data to a VDE-protocol module of a shore platform currently visited by a user according to a routing selection result, or forwards the data to an intra-domain VDESSN module through a Gd interface, or forwards the data to a VDEGSN module through a Gn interface or a Gd interface;

43) after receiving the data from the VDESSN module, the VDEGSN module accesses the HLR/AUC module and the NAT table, and performs security authentication and routing by combining the ODID;

44) the VDEGSN forwards the data to a remote VDEGSN module or an Internet server or other equipment in a heterogeneous network according to the routing result;

exchanging the plurality of data formats between the source station and the destination station through the packet data transmission channel.

2. The method according to claim 1, wherein said performing a plurality of data format exchanges between the source station and the destination station further comprises encrypting/decrypting and decompressing/compressing the transmitted data.

3. The method of claim 1, wherein the source or destination station is a ship station, a shore station, a gateway, a webmaster, an Internet server authorized in HLR/AUC, or a device in a heterogeneous network, and one of the source or destination station is a VDES device.

4. The method of claim 1, wherein establishing the packet data transmission path between the source station and the destination station via the land platform, the VDESSN module, the VDEGSN module, or an external network comprises: establishing a packet data transmission channel in an inbound direction between a source station and a destination station via a land platform, a VDESSN module, a VDEGSN module, or an external network, comprising:

51) after receiving data from an external network, the VDEGSN module accesses the HLR/AUC module and the NAT table, and performs security authentication and routing by combining the ODID;

52) the VDEGSN module directly delivers the data to the current VDEGSN according to the routing result, or forwards the data to the intra-domain VDESSN module through a Gn interface or a Gd interface;

53) after receiving the data from the VDEGSN module, the VDESSN module accesses the HLR/AUC module and performs security authentication and routing by combining the ODID;

54) and the VDESSN module forwards the data to the current VDE-protocol module or the current VDESSN module according to the routing result.

5. The method of claim 2, wherein said performing a process of exchanging the plurality of data formats between the source station and the destination station further comprises encrypting/decrypting and decompressing/compressing the transmitted data, comprising:

the compression process of private IP packets from inside the VDES network all occurs at the source VDES station; the compression process of the IP packet from the Internet occurs in the VDESSN module, and a Multi-protocol Header needs to be added to the compressed IP packet for encapsulation, and the decompression process occurs in a destination VDES platform;

the Multi-protocol Header carries data types, encryption options, compression options and custom option parameters.

6. A VDES-based packet data gateway for use in the method according to any of claims 1 to 5, comprising a VDE-Block module, a packet data state machine, an environment model, a vdesn module, a VDEGSN module and an HLR/AUC module;

the VDE-Block module is used for realizing Az interface primitive message processing between a transmission layer and a network layer, PDU packaging and unpacking format processing and protocol internal parameter processing;

the packet data state machine is used for receiving related parameters of data transmission and skipping the state according to the received parameters;

the environment model is used for realizing generation, transmission and conversion of communication signals between the VDE-Block module and the VDESSN module;

the VDESSN module is used for intra-domain routing, packet forwarding, authentication, encryption/decryption, decompression/compression and GTP session management;

the VDEGSN module is used for routing and packet forwarding outside a domain, protocol conversion, data filtering, NAT and dynamic IP allocation;

the HLR/AUC module is used for storing the information of the platform and realizing the authority access and addressing positioning of the maritime platform, the gateway and the specific network.

7. The gateway of claim 6, wherein the VDESSN module is configured to forward data to the VDEGSN module via a Gn interface (GTP protocol) or a Gd interface;

the VDEGSN module is used for forwarding data to the VDESSN module in the domain through a Gn interface or a Gd interface.

8. The gateway of claim 6, wherein the VDEGSN module further comprises a Mulit-protocol sub-module for performing format conversion on the received or output data.

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