Major Indian GSM Operator

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Major Indian GSM Operator

Flexible and Reliable Solution for SS7 - VoIP Interworking


The end customer is a leading Indian GSM provider operating in several states across the country.


The customer received pan-India UAS (Universal Access Service) licenses and planned to roll out GSM services across the country. Having received spectrum in most regions of India, the company initially launched its services in four regions with plans to expand into the remaining regions. Additionally, it applied for National Long Distance (NLD) and International Long Distance (ILD) licenses and planned to establish a pan-India network for NLD as well as ILD gateways.

The project required linking MSCs from Ericsson and Siemens in the backbone mobile network to a Lucent softswitch and then via SIP to an Avaya Customer Care / IVR system. This would allow calls from subscribers to be handled automatically wherever possible (for standard requests like balance enquiries) but also to be quickly and efficiently routed to the right attendant when needed. Some call flows were quite complex and as a result the acceptance testing covered a wide range of complicated call forwarding and call transfer scenarios.

The system also had to be capable of outbound calls so that call centre staff could contact subscribers about special offers, updates etc.


The solution delivered used AudioCodes Mediant 2000 gateways to handle the physical E1 connections to the MSCs and the transcoding of the media to VoIP. The compact Mediant 2000 VoIP Gateway scales from 1 to 16 E1/T1/J1 spans in a 1U chassis. It also offers:

  • Homologated support for a wide variety of telephony protocols
  • Extensive voice processing capabilities to ensure high quality
  • Dual redundant Ethernet ports and power supply ensuring high availability

The signalling intelligence was supplied by a series of distributed WTL SoIP (Signaling over IP) controllers ( The role of these devices was to provide a translation of the SS7 signalling received from the MSCs into SIP-I as required by the VoIP systems in the call centres.

Naturally, in a round-the-clock customer care application, high availability was essential. WTL and AudioCodes designed a highly resilient network with multiple fail-over and rerouting options to cover all eventualities.

Complete SS7 - SIP Solution

Complete SS7 - SIP Solution
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A spokesman for the operator commented on deployment, "We set some tough hurdles for the suppliers in this project; deployment had to be achieved to a strict timetable to meet our service launch deadlines. Also, our acceptance testing was very rigorous - we had to be sure that anything our customer might need to do would be properly supported. Customer care is obviously a key factor for any mobile operator and I have been very impressed by the reliability and flexibility of this solution – we have a great platform for growing our network".

Munish Bhasin, AudioCodes’ Country Manager in India, added, "This is a large network, when it is fully deployed we will be controlling more than 800 E1s in every major city in India. That’s impressive by any standards and it underlines the position of AudioCodes as the preferred supplier of media gateways to major fixed and mobile operators around the world. WTL’s SS7 solution complemented our gateways perfectly for this deployment and we believe that our joint offering will find success with other customers in the future."

"I think this project is a great showcase for the respective strengths of WTL and AudioCodes," noted Simon Pearson, Business Development Director of WTL, "We have worked together for many years and we know that AudioCodes’ hardware is the best around for VoIP. What we have been able to do here is to add to that WTL’s considerable SS7 and SIP signaling expertise."

About WTL

World Telecom Labs is a Belgium-based company which has long been a leader in the provision of VoIP switches, Pre-Paid applications and signaling gateways for emerging carriers and telecom service operators. WTL has an installed based of 100,000s of voice ports with service providers worldwide switching billions of minutes of VoIP traffic using WTL equipment. For more information about WTL and its products, please visit or email