Next Generation Networks (NGN)

What is a NGN
An NGN can be described as a network that facilitates three things:

• independent access to applications and content
• high availability, high bandwidth core & access network that supports multiple services
• a platform that allows rapid development and deployment of new integrated applications to the end user.

NGNs have taken advantage of rapid advancements in technology, the marked increase in core and access bandwidth capacity, and in a revolutionary way traditional voice traffic is carried over data networks. The terms Voice Over IP (VoIP) and IP Telephony (IPT) were introduced to describe how voice signals were converter into data packets for transport on IP in NGNs.

NGN Drivers
A key driver for implementing or migrating to a NGN is cost. It is impossible to generalise on the extent of cost savings since business specific issues such as service strategy, legacy infrastructure, operational model, and scale all play a part in this complex equation. For many businesses however the potential capital and operational cost savings of running multiple services on a single infrastructure are too good to ignore.

Another important driver is service differentiation. The initial focus of many NGNs is to support traditional data/voice services, but today, there are service providers building complete business strategies around new converged service platforms. They are taking advantage of the benefits convergence provides them today and investing in future proven technology that they believe shall provide a platform for application growth.

NGN Equipment Types
Along with traditional voice and data equipment the NGN architecture contains converged network equipment types such as Call Agents (e.g. Media Gateway Controller - MGC, Gatekeeper - GK, SIP Server and Softswitch - SS), Media Gateways (MG), Signalling Gateways (SG), Feature Servers, Application Servers, Media Servers and provides Management, Provisioning and Billing interfaces.

The Softswitch
Softswitches are a software-based call control device that plays one of the most significant parts in the NGN. The Softswitch provides call control interworking between NGN protocols such as MGCP, H.248 / Megaco, SIP, H.323, and Sigtran as well as more traditional telephony protocols such as CAS, ISDN, SS7, TCAP, and INAP. The Softswitch can contain multiple call agent functions (e.g. MGC, SIP Server & GK) and in some cases a SG function.

One of the many roles of a Softswitch is interfacing to the PSTN (Public Switched Telephony Network). It does this by interworking signalling systems via SGs and the voice circuits via MGs from PSTN switches and Intelligent Network platforms.

The choice of softswitch today is large and is influenced by factors such as target market, scale of deployment, required functionality, available budget and service strategy.

Who are implementing NGNs
Traditional carriers with traditional legacy equipment and services must carefully address how they migrate to a NGN. They must decide whether to replace current operational infrastructures, cap investment & grow organically or implement a new parallel platform & migrate over time. Whatever the decision the scale of network infrastructure involved will lead to significant costs and protracted timescales for migration activities.

New operators with less legacy infrastructure and greenfield networks can plan for, design and implement the NGN more readily. Their IP network can be designed to provide some level of quality, a vendor can be chosen to provide an end-to-end solution and interconnects to the PSTN and Internet can be put in place. Advances Operational Support Systems can be utilised effectively to monitor, control, police and bill with less integration than with traditional operators.

ISPs are looking at a potential change in their business model. Converged services will allow the ISP to differentiate themselves while entering into a new telecommunications market without the capital outlay of traditional networks. Bandwidth increases brought about by DSL to the home will play a major part and so ISPs can offer more bandwidth hungry services without the constraints of slower speed access.

Next Stage of Communications
A lack of expertise and specialised experience with this technology is preventing many organisations from independently evaluating or taking most tentative first steps into the world of converged networking and issues on quality, scalability and the potential regulation have to be analysed and addressed so we can all move to the next stage of communications.

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