Projects Projects

Building of Corporate IP-telephone Network in State Savings Bank of Ukraine Open Joint-Stock Company

Goals of the project

• To design the Bank's corporate IP-telephony network. 
• To build corporate IP-telephony network on the basis of the products manufactured and developed by Cisco Systems, provided that existing telephone infrastructure (on the basis of the existing office telephone exchanges and data transfer channels) will be saved, as well as provided that it will be possible to hold audio and video conferences. 
• To install and adjust hardware and software for IP-telephony network. 
• To create the system, which may be easily extended in future. 

Solution 

Designers of the system have decided to build this system on the basis of family of TCP/IP protocols. This solution is explained by their striving to ensure further development and improve functionality of the existing corporate telephone network on the basis of the most state-of-the-art technologies. Design of IP-telephony network of the Bank is a standard design for the selected convergent direction, as well as for a common family of Cisco AVVID architectures (Architecture for Voice, Video and Integrated Data). 

Basis of the entire Bank's IP-telephony system is an extendable management cluster that works under Cisco CallManager application software. Utilization of clusterization technology with existing scales of the Bank's IP-telephony system is aimed at increase of reliability with the help of redundancy method.

CallManager is intended for centralized processing and signaling of calls, organization of connections, monitoring of terminal devices of IP-telephony network, as well as keeping of the database, which contains information on these terminal devices. The project was implemented with the help of CallManager version 4.x; this version includes special program modules that support video conferencing.

Hardware of CallManager cluster was as follows: dual-processor servers manufactured by Hewlett Packard (model DL380 in configuration with one installed processor). A key component of the Bank's IP-telephony network is a gatekeeper, which is made on the basis of Cisco 7206 router. Cisco 3745 voice gateway within the network of the Headquarter Office plays two basic roles.

The main role: it is used as a gateway for interfacing with the inherited traditional telephone network (such interfacing is made with the help of multiport E1 modules).

The additional role: this voice gateway provides the entire VoIP-network of the Bank's Headquarter Office with computing resources of its "frame" of digital signal processors (DSP; the entire system uses two modules — Cisco PVDM2-64).

G.729 codec with high degree of compression is used in the system for transfer of voice data packages through the channels connecting the Bank's Headquarter Office with nodes of regional administrations of the Bank. Local area networks are based on the less resource-consuming codec — G.711. The second task of Cisco 3745 is to ensure "on-the-fly" transcoding of those data flows, which were processed by different codecs.

One of functions of the Bank's IP-telephony network is to ensure holding of conferences both CallManager, and/or with the help of server of conferences (SoC) — IP/VC 3540. CallManager application program includes special modules, which bear responsibility for program implementation of operation of mixing of data flows with the help of G.711 codec (in order to organize a conference communication mode).

Server of conferences IP/VC 3540 is a modular device, which ensures mixing of data flows with the help of the SoC hardware facilities. This server extends functional capabilities, which concern holding of conferences, as compared with CallManager.

Softswitches of the work group (Catalyst 3550-24PWR; components of 4-th class of AVVID architecture) performs several functions: each such switchboard connects up to 24 terminal devices with the Bank's local area network; in addition, they create virtual local area networks (VLAN) for logical isolation of voice traffic from data traffic.

Results

A device of Cisco IP/VC family was installed in Ukraine for the first time: a device that ensure holding of multipoint conferences. As a result, the Customer has obtained the network, which is integrated to the existing system of management and safety of the Bank's corporate information network and which is connected with telephone lines with the help of digital technologies. Corporate IP-telephony network, which was built, has made it possible to:

• hold audio conferences with employees of both the Bank's Headquarter Office, and employees of the Bank's regional administrations (up to 45 persons);
• monitor state (number of participants, their telephone numbers, time of entry to and leave from the conference), and manage holding of audio conferences in a real-time mode (involuntary removal of a participant from the conference);
• protect access to audio conferences with the help of passwords;
• hold subscribers on line (no more than 5 persons at the same time), readdress and intercept calls.

This conference communication system was tested in different modes of operation: both in the mode of connection of the first Ukrainian server of conferences (IP/VC 3540), and in the mode, when only resources of CallManager are used.

Methods of telephone conferences were tested both within local area network of the Bank's Headquarter Office, and with participation of employees of regional departments. 

Future development of the system was taken into account in the course of its creation. It may be extended without any essential investments to new applications (a Contact Center, video, etc.). IP-telephony network is designed for one thousand subscribers (including those, who are far from the Bank's Headquarter Office); it is possible to increase number of subscribers without hardware and software replacement. The system makes it also possible to add thousands new subscribers easily.

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