Overrunning conventional networks capacity boundaries caused by the nature of the existing multimedia traffic and demands in its multiservice operation has led to the qualitative transformation of the entire network structure. In its turn, this has resulted in creation of the Next Generation Network concept (NGN).

The International Telecommunication Union (ITU) has not yet elaborated the unique interpretation of the NGN architecture and services. At least, the current status has been as described at the moment of this article writing, and no special illusions have to be experienced regarding the situation in the nearest future: the natural process of the telecommunication networks convergence is taking place.

From the position of the NGN data transmission networks, these are next generation Internet networks. From the position of the mobile communication, this generation has been even assigned a special number — 3G. From the position of the conventional telephony, NGN today is perceived as the packet switched network under the Softswitch control supporting broad passband subscriber access and traffic multiservice operation.

The general NGN characteristics determined by ITU and ETSI consist in separation of information transfer functions and functions of information transfer control via network, as well as separation of service and application functions from transmission transport network functions. Thus, the subject of discussion here is the stratified architecture, within which interconnection among components is effected solely via open interfaces. The multiservice network that is being under expansion now in Astana satisfies all described requirements. The structural flowchart of the mentioned network is presented in the figure below.

Fig. 1 Structural diagram of NGN network.

This network core is the software switchboard SURPASS hiE9200 manufactured by the Siemens company, one of the global leaders in the NGN equipment market. The software switchboard consists of the following functional modules (units):

• Call Agent SURPASS hiE9200 is responsible for controlling all network connections;
• media bridge (gateway software) hiG1600 performs the function of a gateway with a public switched telephone network (PSTN);
• media resource server HiR220 serves for voice message processing;
• boundary voice connection controller (single boundary controller — SBC) HiG50 is used for protection of the operator's network infrastructure and ensures inter-network exchange with laminar VoIP-networks, as well as supporting network addresses transformation (NAT);
• SIP-application server SURPASS hiQ4200 ensures supplying business subscribers with the extended application number using the SIP protocol.

Reference: The SIP Protocol is a text-oriented protocol of the applied level assigned for organization, modification and completing different communication sessions including multimedia conferences, telephone links, broadcasting distribution of multimedia information and connecting users to different applications. One of the most important components of the NGN network is represented by multiservice access nodes (MSAN). A multiservice access node SURPASS hiX5630 presents a system possessing 10 slots including 8 universal subscriber slots for the following subscriber linear boards: 72xADSLII+, 48xSHDSL, 40xVDSL, 72xPOTS, 32xISDN, 16xFast Ethernet and 8xGigabit Ethernet in any combination.

As the NGN network transport infrastructure, the IP/MPLS network is used. It is built on the Catalyst 7600 equipment manufactured by Cisco Systems. This project has been developed and implemented by our Company jointly with the specialists of the system integrator — ABS company.

Reference: MPLS — Multi protocol Label Switching — is the data transmission mechanism that emulates different network properties with super-network channel switching with packet switching. MPLS has been developed aiming at providing the universal data transmission service either for circuit switching network clients or packet switching network clients. With the help of MPLS it becomes possible to transfer traffic of any nature, such as IP-packets, ATM, SONET and Ethernet shots.

The NGN network opens wide opportunities for clients allowing their not solely usage of a great number of additional communication services, but creating their own ones as well (service administration through the Internet and on the business subscriber group level). In the latter case, a subscriber is acting as the administrator and uses the single infomedia for additional services organization. One more opportunity of the NGN network consists in individualization of services for a single subscriber and forming the set of services that meets a user's expectations.

Within the range of other important advantages typical for the new generation network there is a high speed of data transmission, mobility (a user's access to data can be effected independently of its location), individuality (services are accessible at any time in the required scope and format of the content submission), accessibility (acceptable price, flexibility regarding the used equipment type).

The NGN network development is planned to be performed stepwise. The following service types will be offered in 2006: access to the public switched telephone network, intercity and international dialing, and basic package of additional services (Basic Centrex). Starting from 2007, the time-phased introduction of new additional types of services is planned.

The NGN network commissioning in Astana will provide for the «KazTransCom» JSC's complying with the task set by the Premier of Kazakhstan, and measures taken by the RK Agency of Informatization and Communication, in the part of tariff reducing and country-wide introduction of the broadband access to the Internet network.