The Many Faces Of A Softswitch
BY LAURA THOMPSON
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The term "softswitch" has evolved over the last 18 months,
and is now very loosely applied to many different products with very
different capabilities. A recent count from the analysts at RHK revealed
over 180 products all claiming to be a softswitch. While the term can be
defined only in very general terms, it is more important to focus on the
types of softswitches that have emerged.
Very broadly, a softswitch provides call routing/call state functions
and controls connectivity within IP networks and between IP and the public
switched telephone network (PSTN). Note that softswitches are different
from media gateways, which in essence provide a physical hardware bridge
between the PSTN and IP networks. Media gateways (also known as media
gateway controllers), require a softswitch to provide additional
intelligence and direct the call routing functions. Some manufacturers
have hybridized the two types of products, adding some softswitch
capabilities to their media gateways.
From these very broad definitions, softswitches are much better
understood if looked at from the perspective of the business problems they
solve. The distinction of whether a softswitch is hardware or software, or
both, is not important; rather, the importance lies in a softswitch's core
competence.
TANDEM/ROUTING SOFTSWITCH
Operating at the network level, and providing connectivity between the
PSTN and an IP network, are softswitches that are often embedded in the
hardware media gateways. These systems provide Class 4 types of network
functions, i.e., moving calls between two networks, and typically have the
robust port densities that service providers require. These initial
softswitches focus on the rapid offload of data (modem) calls from the
PSTN to the Internet and cost-effectively free up TDM circuits for their
intended purpose, i.e., voice traffic.
They are also used for packet-based "tandem routing"
functions so that calls can traverse the PSTN effectively. The goal of
this softswitch is fairly simple -- to provide call control, call routing,
and interconnection at the core of the network and interface with the SS7
network. When compared to a traditional tandem switch, they offer
significantly lower capital and operational costs. These Offload/Tandem
routing softswitches provide a cost reduction strategy to help service
providers transition their circuit-switched networks to a packet-based
infrastructure that allows for cheaper transport.
CALL COMPLETION SOFTSWITCH
Another type of Class 4 functionality, also at the core, offers
capabilities like "call completion" services such as pre-paid
calling cards and automatic dialing of 411 information calls. These used
to be called service nodes in the old AIN framework and were typically
devoted to specialized applications. These services can be delivered more
cost effectively over a packet-based network, but more importantly
deploying this type of softswitch begins to represent new revenue
opportunities for service providers. Call Completion Services softswitches
are relatively new, but they will become prevalent as IP-based voice
services gain recognition.
CLASS 5 REPLACEMENT
In the last year softswitch technology has accelerated rapidly beyond the
narrow functionality of Class 4 softswitches, to newer softswitches with
features normally attributed to Class 5 switches directly controlling IP
endpoints. There are three significant categories of Class 5 softswitches
on the market today. In general these softswitches are responsible for
initiating call set up and tear down at the edge of the network, but like
Class 4 switches, they tend to focus in on certain business problems to be
solved. The three categories offering basic Class 5 replacement services
are POTS/Residential softswitches, End Office/IP Centrex softswitches, and
the Applications-Enabled softswitches. Each category of Class 5 softswitch
provides a feature set designed to serve different kinds of applications.
POTS/Residential
The "POTS/Residential" softswitch offers the basic features
residential customers expect such as call forwarding and call waiting.
They tend to replicate current residential switch capabilities (in a
software-based environment) so that the capabilities become much more
cost-effective for a service provider to manage. POTS
"residential" softswitches will serve the needs of many service
providers who want to offer call forwarding, call waiting, caller ID, and
other popular consumer packages.
End Office/IP Centrex
The next level of Class 5 softswitch is focused on what is typically
referred to as End Office/IP Centrex capabilities. These softswitches
offer more business-oriented functionality, such as call conferencing,
call hold, call park/pickup, hunt group routing, etc. In addition to
replicating commonly used office features, these softswitches have added
some Web-based provisioning, which will make these traditionally complex
services much easier to manage for the service provider. The end-office
applications on these softswitches enable a small or medium-sized business
(SMB) to replace current Centrex offerings with the same familiar
functions, add a few more capabilities, and function from a
point-and-click browser, rather than from difficult-to-remember key codes.
Applications-Enabled Softswitch
It is the next category of Class 5 softswitches, the Applications-Enabled
softswitches, which bring about a fundamental shift in the manner that the
softswitch is implemented by being application-centric versus
telephony-centric. These softswitches are architected in a manner that not
only allows advanced applications to be quickly introduced but also
provides a natural mechanism for interfacing with other hosted
applications, both within a service provider's network and the Internet.
The applications with these softswitches give service providers new
financial reasons for implementing a softswitch, moving from simple
cost-reduction, and selling services for less, to significant new revenue
generation based on innovative, compelling new services. These
applications offer the hosted model of telephony that made Centrex
initially popular, but focus on offering advanced PBX functions and new
innovative services not typically found on business phones, such as mobile
phone features like viewing missed calls, click to dial, or even e-mail a
response. End-office users save from $20K to $50K in equipment costs,
since they no longer need an in-house telephone system, effectively
outsourcing this requirement to a service provider while gaining more
control over the management of their telephony on an easier-to-use
Web-based portal.
Because applications-enabled softswitches sit at the edge of the
network and have an open API with a separate layer for applications, they
are ideally suited for development and deployment of many advanced
telephony applications. The rich applications combine the benefits of data
and telephony to offer new capabilities that users will purchase. Since 80
percent of overall industry revenue comes from voice services, service
providers need innovative, voice-oriented applications to generate new
sources of revenue. In this highly competitive market with decreasing
transport prices and profitability, innovative services that go beyond
these basic features are essential for customer retention and increased
profits. Additionally, these new telephony applications are designed to be
easy to provision by the service provider and/or an office manager at the
SMB. The telephony applications on an applications-enabled softswitch can
not only be delivered more cost efficiently and quickly than voice
transmission, they have greater value to both the service provider and the
end-office user.
Feature Servers
There is a small group of applications servers, called feature servers
that are often confused with the Class 5 softswitches. However, this group
lacks call control functionality and provides the applications only. They
are more toolkit-oriented and designed for building
services; they require the addition of a softswitch like
a "POTS/Residential" type to provide call handling
and routing. As a result, the applications that are developed are limited
to what the underlying softswitch can support.
CONCLUSION
Going forward, end-users will demand more applications tailored for
special situations such as vertical markets, which are very easy to create
on the Applications Enabled softswitches. In today's financial climate,
service providers will need the new sources of revenue they can achieve
only with these advanced technologies. Thus, the future revenues of the
industry may very well depend on these new Class 5 softswitches. It will
be important for service providers to determine which application set(s)
and which business problems they really are trying to solve when
evaluating different softswitches.
Laura Thompson is vice president of marketing and business
development at Sylantro Systems. Sylantro's applications-enabled
softswitch is designed to allow service providers to deliver high value
telephony services. The company's solutions are an advanced breed of
managed telephony services that render Centrex and PBX offerings obsolete
and provide additional popular capabilities. Sylantro transforms the way
communications applications are used and delivered -- doing for telephony
what the browser did for the Internet. Visit them on the Web at www.sylantro.com.
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