The application gateway performs protocol conversion on the application layer. For example, one host performs ISO e - mail standards, and the other hosts Internet e - mail standards. If these two hosts need to exchange e-mail, they have to pass an e-mail gateway for protocol conversion, which is an application gateway. NCP is a protocol that works on the seventh layer of OSI to control the interaction between the client station and the server, and mainly completes the opening, closing and reading of the files in different ways.
Signaling gateways, relay gateways, and access gateways:
Signaling gateway SG, which mainly completes the relay of signaling messages between the 7 signaling network and the IP network, in the early 3G, the transfer of messages between the access side to the core network switching (the RANAP message between 3G, the BSSAP message between 3G and 2G), and the transfer of ISUP messages between 2G MSC/GMSC and the soft switch.
The relay gateway is also called IP gateway, which also meets the needs of telecom operators and enterprises VoIP devices. The relay gateway (IP gateway) is constructed by the relay board and the media network. The single board can provide 128 channels of media conversion, two Ethernet ports, and the frame adopts the leading CPCI standard. The capacity expansion is convenient with high stability, high reliability, high density, large capacity and so on.
The access gateway is a media access gateway based on IP's voice / fax service. It provides efficient and high quality voice services and provides VoIP solutions for operators, enterprises, communities, and residential users.
Besides, gateways can also be divided into protocol gateways, application gateways and security gateways.
Protocol gateways usually use protocol protocols to transform protocols between different network areas. This transformation process can take place between the second, third or 2 or 3 layers of the OSI reference model. But there are two kinds of protocol gateways which do not provide the functions of transformation: security gateway and pipeline. Because of the logical differences between the two interconnected network areas, the security gateway is the necessary intermediary between two technically similar network areas. Such as the private Wan and the public Internet.
Application gateway is a system to translate data between different data formats. A typical application gateway receives input from a format, transmits it, and then sends it in a new format. The input and output interfaces can be discrete or connected by the same network.
Application gateway can also be used to connect LAN client to external data source, which provides local host with connection with remote interactive applications. Putting the application's logic and execution code in the LAN client avoids the shortcoming of the wide area network with low bandwidth and high delay, which makes the response time of the client shorter. The application gateway sends the request to the corresponding computer, gets data, and transfers the data format to the format required by the client if necessary.
Security gateway is an interesting fusion of various technologies. It has important and unique protection function. Its scope is filtered from protocol level to very complex application level filtering.
It can be said that gateway is a computer system or device to transform important tasks. Gateway is a translator between two systems that use different communication protocols, data formats or languages, or even different architectures. Unlike bridges that simply convey information, gateways repackage incoming information to meet the needs of the target system. At the same time, gateway can also provide filtering and security functions. Most gateways run on the top level of OSI 7 level application layer.
Address：Address: Add:No.640 FengQing St,DeQing, Zhejiang,313200 China
America District, Europe District