Method, media gateway and network system for realizing network address conversion

Abstract

The invention discloses a method, a media gateway and a network system for realizing network address conversion. The method comprises the following steps of: acquiring address mapping relation which is sent by a media gateway controller and comprises a first address of a first network, and a second address mapped from the first address, a third address of a second network, and a fourth address mapped from the third address; modifying the first address used as a source address in an IP message sent from the first network to the second network into the second address according to the address mapping relation, and modifying the fourth address used as a destination address in the IP message into the third address and transmitting the third address to the second network; and similarly, carrying out source address and destination address updating of the address of the IP message sent from the second network to the first network. In the technical scheme, the media gateway can map both the destination address and the source address of the IP message to bridge two networks with overlapped address fields and solve the problem of address conflict.

Description

technical field [0001] The invention relates to the communication field, in particular to a method for realizing network address translation, a media gateway and a network system. Background technique [0002] A network system is usually divided into multiple subnets, and each subnet is connected to each other through a gateway. For example, the next generation network (Next Generation Network, NGN) with softswitch equipment as the core, its network structure is as follows: figure 1 shown. The NGN network mainly includes a media gateway (Media Gateway, MG) and a media gateway controller (Media Gateway Controller, MGC). Among them, MGC is used to realize the management of call state and the control of MG bearer resources; MG is used to convert the media stream type from one format to another format, for example, to convert the E1 time slot in the circuit switched network The media information in the IP network is converted into a real-time transport protocol (Realtime Tran...

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Problems solved by technology

[0013] In the process of realizing the present invention, the inventors have found that the above two kinds of NAT only translate the source or destination address (or also include ports), when a site improperly uses the public IP address that has been assigned to other institutions to conduct When addressing; when a site changes from one operator to another and wishes to retain internally the addresses assigned by the previous operator (which may reassign these addresses to other In these cases, conflicts between the internal addressing domain and the external addressing domain will occur, and the existing NAT cannot resolve this conflict

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