In the coming years, service providers face the task of integrating new
voice-over-packet technology with their existing infrastructure. With data
traffic outpacing voice, carriers will need to transmit data
cost-effectively and cap spending on legacy equipment while investing in new
technologies. There are many factors that must be considered in their
network and services planning -- including such critical aspects as capital
budgets, scalability, interoperability, reliability, service creation
flexibility, application requirements, and physical installation
Clearly, the appeal of the softswitch in next-generation networks (NGN)
is that it is an unbundled alternative to the expensive, proprietary circuit
switch in the PSTN. Through softswitching, a distributed architecture and
centralization of intelligence provide economy through the inherent ability
to adapt, change, and scale. This unbundling translates to lower start-up
and operational costs, reduced dependence on switch manufacturers for
service development, and dramatically compressed lead times for new service
The service providers, however, will have vastly different requirements
for the softswitch solution depending on their particular market or
implementation scenario. For example, an enterprise adding a voice overlay
to an existing ATM network needs a very different implementation than an IXC
considering Class 4 tandem switch replacement, an ILEC planning to add
out-of-region service, or a CLEC requiring an Internet offload solution
The Right Solution For The Right Price
Rather than relying on a "one-size-fits-all" box, the successful end-to-end
network vendor needs to create a family of softswitches, with a price point
and capacity structured to match the needs of specific customer
implementations. Each softswitch delivers the required capacity to drive
particular applications or services. The products, based on a scalable,
common hardware platform, can be easily upgraded to the next higher-capacity
product. The matched set of application and hardware platforms is key to
providing the "right solution at the right price" for all customers.
In general, switch requirements will be greatly affected by application
content and location in the network. Service at the edge of the network will
require more applications and, therefore, will be more complex. Adding CLASS
services to a tandem replacement media gateway controller (MGC) will have
the negative effect of reducing capacity, increasing complexity, and causing
more switch interdependency. However, feature control can be separated from
the MGC with the addition of an application feature server to help reduce
the complexity of service creation and implementation and allow further
customization. This additional unbundling drastically lowers the cost
barrier to enter new markets and achieves unprecedented economies of scale.
Greenfield carriers, for example, can outfit new markets with media gateways
and feature servers controlled by a centralized MGC, instead of full-blown
Class 5 switches. Incumbents can maintain the same service quality by using
larger gateways in established markets and smaller gateways in new
out-of-region markets under control of a location-independent MGC cluster.
The Impact of Softswitch Applications
A distributed packet tandem application must allow the carrier to cap their
investment in circuit switches by delivering the features of a traditional
Class 4 switch -- flexible routing and number translation, N00/888
translations, routing restrictions, authorization, and screening. Due to a
substantial installed base and large call volumes, the critical performance
characteristic is call capacity, likely in the range of 800,000 busy hour
call attempts (BHCA) including consideration for ever-present AIN dips.
However, for Internet offload, the requirement is essentially to redirect
Internet-bound traffic from the overtaxed Class 5 central office switch to
the packet network. Call capacity requirements for this particular
application may only need to be 250,000 BHCA, largely due to the longer hold
times associated with data calls. Customers in this category are inclined to
pay for scalability but not unneeded capacity.
Fulfilling The Promise
Network implementation requirements will obviously vary, and the softswitch
product offering will be segmented in order to optimize the value
proposition to the customer. The service provider will effectively choose a
network element according to call performance, feature support, and pricing.
In-service capacity upgrades and added feature provisioning will be added as
required, quickly and easily.
A segmented softswitch product line facilitates the migration to
packetized voice networks for both early adopters and incumbents alike. It
fulfills the promise of operational cost savings, increased flexibility, and
differentiated service offerings for all customer implementation scenarios.
In the adaptable, open architecture of next-generation networks, one size
softswitch does not fit all.
Richard (Dick) Hayter is the assistant vice president of marketing for
the Network Systems Division of Tekelec.
Tekelec, a leading supplier of signaling and controls systems, develops
innovative network switching and diagnostic solutions enabling the
convergence of traditional and converged wireline, wireless, and IP voice
and data communications networks. The company also provides products and
solutions for call centers and other telecommunications markets.
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