Migrating TDM Networks to NGN | A US Case Study

This Case Study will describe how Squire Technologies has delivered such a solution to its US based client Coretel.

In 2007 Coretel required a flexible, low CAPEX solution to deliver their large-scale modem dial-up services. Their requirements at the highest level were: -

• Low initial CAPEX
• Scalable
• Flexible multi-functional network solution from a single vendor
• Support for a distributed architecture
• Support for centralised database routing
• Future proof – single solution that would allow them to deliver NGN/VoIP services

The system is roughly delivered in 2 x sections. At the interconnect to the SS7 Carrier, Squire Technologies supplied a pair of dual redundant STPs. Their purpose is to provide signalling aggregation to Coretel's network.

Quite simply they allow Coretel to interconnect to the SS7 carrier over a limited number of signalling links and then aggregate the signalling out to the remote POPs over their own internal network.

Significant Cost Savings

The clear benefit is the cost saving made with the reduced number of SS7 links needed at the carrier side. If the SVI-STPs were not supplied to perform signalling aggregation the network would look like this.

TDM Network without Signalling Aggregation

In this network architecture each remote POP would need to interconnect directly to the SS7 carrier over SS7 A-links – obviously there is an attributable cost for each SS7 A-link, plus there is a lengthy interconnect process to go through each time a new POP is deployed.

Cost Comparison

Clearly this system needed to be distributed – with up to 13 x MGCs/MGs deployed at local POPs across the US. Signalling back-haul from the STPs to the MGCs/MGs is achieved simply by using industry standard SIGTRAN M2PA available on all Squire Technologies SS7 products.

The SVI-MGC is a scalable SS7 Media Gateway Controller that is compatible with standard Cisco, Lucent and AudioCodes Media Gateways.

In this instance Coretel utilise Lucent TNT/APX Media Gateways to deliver the dial-up modem services.

These remote POPs were rolled-out over a 12 month period – the SVI-MGCs were installed and configured remotely onto servers supplied and supported by Coretel.

In 2010 Coretel wanted to start to deliver NGN VoIP services over SIP. Did this require a complete overhaul and replacement of the current TDM network? No it simply meant configuring the SVI-MGCs to use the native SIP support and configuration changes on the Lucent Gateways to support new media types.

Of course it wasn’t quite as straightforward as this as now the system was evolving to support both a TDM and a NGN network. What was needed was a routing engine that would allow calls to be routed either as purely TDM or SIP.

The solution was to activate the native support for SQL on all Squire Technologies products. This allowed Coretel to build and manage, using their expertise and business knowledge, a centralised SQL Routing Database. The centralised database is then queried by the remote SVI-MGCs to allow calls to be correctly routed out over SIP or TDM.

This shows quite clearly how using the existing built-in VoIP and SQL support on all SVI products allowed Coretel to move their business from pure TDM to TDM & NGN.

TDM & NGN Network Overview

The story obviously doesn’t stop here. There are a myriad of business plans Coretel might consider as they expand their NGN service: -

• Provision of AIN LNP ( Local Number Portability ), CNAM or 800 services
  • Fully supported across SVI-STP/SVI-MGC To deliver more VoIP services Coretel may need to add further business logic to the centralised database or introduce another database at the STP.
• Change their Media Gateway vendor
• Take advantage of the more exotic NGN protocols available – SIP-I/SIP-T
• Simplifying their VoIP network at the network edge with the recently released SVI-SBC – Session Border Controller.
• Adding SMS functionality with the SMSG – SMS Gateway
• Utilise the SVI-Billing add-on to provide comprehensive support for Wholesale Billing and multi vendor support

Whatever the next steps Squire Technologies are committed to building products that are flexible, integrate easily into existing networks with built in future proofing for the NGN long term.

For further information on how Squire Technologies can provide an effective NGN solution click here or download the presentation below.

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