The Transition Agents

As technologies for carrying voice and data mature and converge, service
providers and enterprises are increasingly viewing voice over packet (VoP) based
network as a way to reduce communications costs, boost end-user productivity and
enable new applications. Such network architectures not only handle multiple
kinds of traffic in a cost-effective way but also competitive services, which
integrate voice, data and multimedia, which are going to be the key

Operators’ Strategy

When considering the deployment of NGNs, strategy of a telecom operator is
going to depend upon its history (incumbent vs green field), market situation
(deregulated vs monopolistic, strength of competitors), status of its networks
(single equipment provider vs several, recent or less recent products), and the
evolution of its customers’ needs (traffic, services, etc).

For the operator, some of the key reasons in favor of NGNs are to:

Niraj K Gupta

operators want to protect the large investments made in the access
nodes. Hybrid platforms that exhibit features of TDM and allow
evolution to softswitch are the answer

l reduce time to
market for new technologies and services
l facilitate vendor,
carrier, or third-party development of software
l reduce operational
complexity by standardized modular systems
l separate call
processing from switching/transport function through open interfaces

The associated objectives underlying this approach would include:

l support ATM and
IP connections in addition to legacy TDM connections
l keep the present
level of voice features when evolving from TDM-based networks to VoP solution
l support voice,
video and data services

To address these needs, the vendors are developing NGN solutions (including
call servers/softswitches, trunking and access gateways, IP/ATM networks nodes,
etc) to cope with the actual requirements of different operators, and are
offering traditional voice services as well as advanced new multimedia services.

The new operators may directly install softswitches and gateways (trunking or
access gateways) to handle the Class 4 or Class 5 applications. However, Class 5
application on softswitches will take some time to develop. So they look for
platforms, which can provide Class 5 applications on TDM at present, but which
can migrate to NGN smoothly.

Large installed base of TDM-based traditional networks, make the incumbent
operators look for a smooth transition to the full NGN architecture, to protect
the large investments already made in the access nodes. Hence, they look for
hybrid-platforms, which can give all the features of TDM and evolve to a
softswitch–integrated inside the TDM switch itself–ensuring migration of
subscribers from the TDM environment to the NGN environment, without any

Platforms being designed for these large incumbent operators address the
following requirements:

n investment
protection by reuse of the installed switches as well as external devices, such
as IN service control points, network management centers or customer-care and
billing systems
n networks’ smooth
evolution without service disruption
n functional
continuity of features and services

NGN Network Strategy
Existing networks, catering to separate voice and data transports, can be
optimized by the introduction of new high-capacity switches to drastically
reduce the number of switches and thus, the OPEX costs.

At access level, voice and data convergence is already happening through mass
deployment of ADSL on copper lines. At the transit level, NGN is implemented
initially via VoP transport with stand-alone call servers (Class 4 or transit
call servers), controlling trunking gateways in charge of the PSTN-to-packet

Introduction of the media gateway controller (MGC) feature in TDM switch,
enables the operators to move smoothly to NGN with full continuity of services
at the desired deployment pace. MGC allows control of additional gateways, which
interconnect existing access unit/trunk to packet network.

This solution allows a progressive hand-over of voice traffic from the TDM
world to the data world, while retaining the existing end-user services as well
as the control and management interfaces. This would ensure networks’ smooth
evolution without service disruption, besides investment protection. n

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