With the development of network communication technology and the evolution of 3rd Generation Partnership Project (3GPP), asynchronous transfer mode (ATM) network will gradually join Internet Protocol (IP) network, and even will be replaced by the IP network. However, since resources will be wasted when replacing the currently available ATM network with the IP network and at the same time it still lacks practical networking and operating experience to use all-IP technology (in particular as to the IUB interface, wherein the IUB interface is an interface between the radio network controller (RNC) and base station node B (Node B) defined in 3GPP), the evolution of ATM network to IP network is gradual. Thus, the network elements which need to communicate may not directly communicate with each other due to different transfer modes, for example, the currently available NodeB devices use ATM transfer mode while RNC uses IP transfer mode.
Furthermore, the universal mobile telecommunications system (UMTS) introduces high speed downlink packet access (HSDPA) and high speed uplink packet access (HSUPA) services in the 3GPP R5 version, and the bandwidth requirements of the IUB interface increase a lot as compared to that of 3GPP R99/R4. If the Node B and RNC still use the point-to-point connection mode via the IUB interface, then on one hand, it will cause the links between the RNC and a plurality of Nodes B to be independent from each other and not be able to be multiplexed or shared. When the services of one certain Node B are relatively less, the transfer resources of the Node B and the RNC are wasted. Due to the introduction of HSDPA and HSUPA services, the wasted bandwidth can be up to tens of megabytes. On the other hand, if the point-to-point networking mode is used, it will be required to rent or deploy a network with a low speed link, the total fee of which is however far higher than that of a high speed link with the same bandwidth.
In addition, in 3GPP 25.933, access link control application protocol (ALCAP) over IP is recommended as the carrier control protocol of universal mobile telecommunication system radio access network (UTRAN), and in the SIGTRAN protocol suite of rfc, there is also provided a control plane gateway for converting the No. 7 signaling to the IP signaling. However, there is no such gateway in the user plane to cooperate with the control plane gateway to form a complete gateway.
It can be known from the above that in the current relevant art if the transfer modes of the network elements which need to communicate with each other are different, then they are unable to communicate with each other directly, thus it makes the networking devices which use IP transfer mode unable to be compatible forwardly with those networking devices which use ATM transfer mode.