Introduction

BTL has opted for Next Generation Network (NGN) Solution for its LDI Network. This choice enables BTL to keep instep with the ever changing and demanding service requirements of the future, without compromising the present requirements. BTL has the capability of carrying voice, video and data, by deploying a truly integrated network.

Building Block of BTL's LDI Network Elements

BTL's LDI network is based on the following building blocks as shown in the table below:

BRIEF TECHNICAL OVERVIEW OF NETWORK ELEMENTS

1. Softswitch

BTL's Softswitch is based on true nextgen architecture providing complete CLASS 4 & 5 feature set. The Softswitch is hosted on high availability NEBS compliant SUN platforms well suited for carrier grade applications. The Softswitch design is modular and scalable, enabling the incremental growth of the core network, by adding one Call Server at a time. A fully configured SSW can handle 5 Million BHCA.

In addition to switching the traditional TDM Trunks, BTL's SSW supports widely used VoIP call control protocols like SIP and H.323. It uses MGCP to control the Media Gateways, with the option to use H.248 for future deployments.

BTL chose Xener as the Softswitch vendor. Xener is a young Korean company credited with developing an NGN driven Softswitch. Xener was the preferred vendor for BTL, because the company comes with zero legacy overhead. Xener showed the flexibility and the commitment to adapt to the evolving requirements of BTL.

2. Application Server (AS) & Media Server

The Application Server and Media Server combo are being used to deliver value added services. These services include Calling card, conferencing, 1-800 to name a few. The two network elements use industrial grade SUN and Intel platforms, catering to mission critical environments. Once again the vendor of choice was Xener, to ensure seamless integration with the rest of the network.

3. Trunking Media Gateway (TG)

BTL is using the industry standard Nuera Media Gateway for all the national and international TDM interconnects. Nuera products come with a rich track record of serving the most unforgiving telecom environments. BTL has deployed GX8 and GX21 series of Media Gws, carrier class Media Gateway that operates at 99.999% availability with NEBS-3 certification. The system can support capacities of up to 68 E1/T1 in a single chassis.

BTL's Media Gateways support a wide range of Codecs and compression algorithms with superior voice processing capabilities, i.e. echo cancellation, lost packets recovery, adaptive jitter buffer and Voice Activity Detection. It caters to MGCP and has the option to handle H.248 for SSW inter-communication.

4. Routers

BTL selected Juniper as the technology partner for all its routing needs. Juniper's M10i and M7i, carrier grade routers, have been deployed in the core and the edges to transport and route IP packets.

5. Network Management System (EMS)

The BTL team has configured HP NNM to manage the entire network. All the 150+ network elements are mapped onto BTL's NMS directly or through select Element Managers, i.e. Xener and Nuera elements which are managed and configured through their respective EMS '.

The complete network, starting from the AC feed to the TDM port, is monitored 24x7. All level of alarms are notified through email to the concerned support team. Critical alarms are notified via SMS enabling prompt action. The NMS comes with a tightly coupled trouble ticketing and email management system to log and track problems and their subsequent resolution. Problem escalation procedures are in place to automatically tag and notify issues that stay unresolved beyond a certain time.

All the critical installations (at the POP) are manned through surveillance cameras coupled with environment sensors.

6. Billing Server

BTL is using a multi-purpose Billing server to meet a broad spectrum of user requirements, ranging from individual customers to corporate customer extending all the way to interconnect partners.

BTL's billing system can record and process post-paid and prepaid call records. It includes a powerful rating engine to handle a wide variety of call charging scenarios. In addition to the conventional billing features targeted towards individuals and corporate, the billing system also manages carrier settlement, catering to different billing cycles and time zones.

7. Power Sourcing

The power arrangements at the NOC (Network Operation Center) and the 15 POPs carry a mix of NEBS compliant rectifiers and inverters, complimented by battery banks. This provides the short-term backup. The NOC is covered by a Genset to cover long-term outages.

8. International Connectivity

BTL's network is connected to the rest of the world through terrestrial IP (internet) and IPLC (clear pipe). Secondary VSAT linkage through INTELSAT provides the alternate backup connectivity.

Both the IPLC and the satellite linkage terminate at the London POP, located at Telecity (Telehouse). The London TelePOP includes a Nuera Media GW, a Juniper router and a Siemens switch to handle both TDM and VoIP traffic. The Nuera equipment also doubles as a compression node to achieve optimum bandwidth utilization over satellite.

9. Network Reliability

BTL has invested serious money and time in designing a highly reliable network , removing all possible SPOF (single point of failure). Redundancy has been built into the system both at the element and at the link/connectivity level.

Each element is running in Active/Standby mode, with standby taking over in case of failure without service interruption. Link outages only lead to higher congestion, but the traffic keeps flowing. From power to routing to switching to transmission, all areas are covered against possible outages.

Systems and SOPs are in place to quickly identify and then rectify the problem to bring the network back to optimum level in the shortest possible time.

Call Centre

BTL has also established Customer Service Department which comprises of highly trained Customer Service Representatives (CSR) equipped with latest IT tools to provide high quality customer services 24 hours a day. Their focus is not only to provide services to individual and corporate customer but also handle the trouble tickets regarding issues raised by international interconnect partners. They have also played a significant role in building Burraq's repute through telemarketing. This online system is playing a pivotal role in ensuring highest quality services by BTL.

BTL's LDI Solution

Our solution complies to the requirements of VoIP systems and TDM with proven technologies. Unique in its approach, the proposed Softswitch architecture supports the maximum flexibility to incorporate service scenarios and adapt to the requirements of existing networks.

The media gateway is responsible for ensuring high availability voice interfaces and ensuring voice quality through its voice processing features and compression algorithms.

The gateway is utilizing existing IP network and is centrally managed by the Softswitch which is responsible for managing routing information and setting up calls between the gateways. The Softswitch is also managing SS7 signaling.

Our LDI network architecture differs from all its competitors in one vital aspect. The existing TDM vendors approach was, and still is, to offer vertically integrated solutions, thus maintaining their hegemony over the customer's network. This approach while advantageous for the vendors by ensuring all components are sourced from a single vendor is detrimental for the service providers. This vertical integration stifles innovation and new service offerings, hinders new revenue streams, and reduces competitive pressures on component pricing.

Our network gives the best mix of access technologies to diverse customer requirements, switching technologies, applications for revenue generation and network management to reduce operation expenditure.

The network diagram shows the connection between the 15 POPs and international POP via satellite.
[Click the image to view larger version]

Our Network is configured to handle:

• 5000 Voice Ports.
• 250,000 BHCA.
• 100,000 subscribers.
• 35 million mins/month

This configuration/capacity is for Phase-I deployment i.e. with 15 POPs. The Network is scalable and adaptable to expand with the service requirements.

Quality of Service & Connectivity

BTL strongly believes in providing the best quality of service and connectivity to all its customers. PTA has also set tough quality standards for the operators and is monitoring operations on regular basis.

The entire process starting from testing to production is covered by highly skilled technical staff to ensure highest standards of service. BTL is committed to quality imperative using process controls and hopes to achieve ISO 9000:2001 standard in short time frame. To achieve this end, BTL has engaged experienced quality assurance professional right from the inception of the project.

To ensure quality and dependability, the entire system has been designed with the very best of the breed components. The components which affect the voice quality and availability are carefully chosen to ensure highest level of end user experience. Even in case of IP connectivity, network node points have been created in UK as well as US to ensure lowest levels of latency.

To ensure high ratio of call completion, BTL started with the strategy to start operations from all the 15 POPs from the very beginning. In addition it is in the process of adding additional PoPs to further avoid congestion the incumbent's transit network. BTL has already established PoP in Gujrat and will shortly add PoPs in central region.

BTL is also in the process establishing direct interconnect with other operators, e.g. the mobile operators. The aim in this case is to improve the call completion ratio as well as provide alternate to congested transit facilities from the incumbent.