Convergence Comes To Life
Integrating SIP Into Existing
BY ARON AICARD
As businesses move toward the converged communications model, a common
concern remains -- how to best leverage existing hardware and software.
New technologies -- SIP in particular -- present opportunities for
maintaining initial investments during the transition into a converged
solution. Although SIP is a critical component in tomorrowï¿½s IP
architecture, it is not just for new installations or forklift
transitions. Instead, SIP can immediately impact and enhance existing PBX
systems, leveraging the benefits of todayï¿½s integrated applications.
The introduction of VoIP has allowed communications models to break
free of limitations imposed by circuit-switched connectivity, allowing for
ï¿½limitlessï¿½ potential in the telephony industry that the data industry has
enjoyed for over a decade. This is due primarily to the ability to treat
communications as pure data from start to finish or end-to-end. This new
flexibility is a fundamental contributor to the excitement behind VoIP and
helps to justify the financial investments being made to further its
IP telephony fundamentally changes the communications model and in
doing so, requires that certain mid- to-high-level protocols exist in
order for software to truly leverage its benefits. SIP brings a necessary
level of structure to IP telephony so applications can expand, multimedia
communications can be blended more seamlessly, and interconnectivity can
become the norm instead of the exception.
SIP is the connectivity protocol that creates, in essence, ï¿½tunnelsï¿½
through which communications can occur, and brings with it a structure, or
model, around which an entire communications solution can be built. The
model of SIP is simple, modular, and extendable -- developers can focus
less on how to connect everything together and more on what to do once
itï¿½s all connected.
In order for any business to decide how to transition into a SIP model,
they must first understand how to evaluate the benefits that SIP offers.
New features and capabilities (the ï¿½limitlessï¿½ potential) offer functional
benefits. Capital investment and cost of ownership define economic impact.
Product options and vendor relationships provide unparalleled options when
it comes to selection.
Function as a priority requires that SIP be added to the center of the
communications platform -- the most significant area in which SIP can have
a positive functional impact. At the center you have the software that
provides most of the features that people use and need, from simple call
handling features such as transfer/conference, to system features such as
transparent networking, Automatic Call Distribution (ACD), and Record A
Call. This software additionally comprises most or all of the integration
between applications. Adding SIP to the center of the communications model
gives the applications -- and most of the system intelligence -- the
freedom to expand the way they communicate with each other and with edge
devices (e.g., phones and gateways).
Economic benefits are realized when SIP either lowers the initial
investment (short term) or lowers total cost of ownership (long term) or
both -- resulting in a positive return on investment (ROI). While the
short term benefits are easily understood through price comparisons, the
long-term advantages are less tangible and require particular assertions.
For example, a business that pays for an IP phone or IP gateway with SIP
capabilities today, will discover investment protection down the road if
they need to change out software at the center. SIP will allow that
business to keep the phones they already own and simply change out the
central components. The main assumption is that new components purchased
later will match up with the current SIP phones to deliver a strong
functional solution. Since a large majority of system features come from
the core, SIP-enabled phones alone cannot protect or guarantee long-term
With the wide range of interoperability delivered with SIP
connectivity, businesses can choose from a broad variety of products,
allowing organizations the freedom to decide who they buy from, what they
purchase and when they make changes. This freedom extends beyond brands,
manufacturers, and integrators, putting decision-making back in the hands
of the business, further improving functional and economic benefits.
A CONDUIT FOR CHANGE
As businesses migrate toward a SIP-centric model of communications,
they should consider SIP as the conduit through which change can occur.
Some of the areas SIP improves on, such as instant messaging and presence
management, can be integrated with existing software and equipment as an
intermediary step toward the future and deployment of full IP systems.
When SIP is implemented properly, digital and analog phone users can
access benefits without upgrading their phones. This allows businesses to
maintain control over transitioning without incurring significant expenses
-- key to operational performance.
SIP has already proven to be an effective tool for merging tomorrowï¿½s
pure TCP/IP and SIP architecture together with todayï¿½s installed
equipment. The following list illustrates some of the things that can be
done with existing PBXs if SIP is introduced at the center of the model.
- Including SIP phones and soft phones as normal extensions along with
digital and analog phones.
- Connecting PBXs together.
- Delivery of instant messages on traditional display phones.
- Allowing regular phones to be monitored on an instant messaging
network for improved visibility into status (e.g., on call) and
availability (e.g., away, at lunch, etc.).
- Voice calling directly between instant messaging clients and
- Inbound ï¿½trunkï¿½ calls from the Internet.
- Multi-vendor interoperability.
- Wireless PDA integration.
- Blending voice, video, and chat calls using existing phones, PCs, and
- Using IP gateways as trunk interfaces to the phone company in
THE REAL WORLD PARADIGM
In the pure SIP model of the future, all components (call processing
software, integrated applications, phones, etc.) know how to use SIP, and
many new things are possible. In the real world of today, few businesses
are in a position that allows them to set everything aside and start
fresh. The economic impact alone requires that a planned transition occur.
This requires business needs and technology to respond to each other.
When SIP is properly evaluated and added to the platform the business
is using today, both short- and long-term benefits are observable. If SIP
is added only to edge devices, businesses will have a difficult time
realizing improvements in the short term. SIP-enabling the core software
allows organizations to immediately begin leveraging new functional
improvements, which translates to improved communications and more
SIP is delivering new benefits in todayï¿½s communications environment,
while helping organizations maintain control over how they introduce new
technology. When implemented appropriately, SIP can be the critical link
between the reality of today and the vision for tomorrow.
Aron Aicard is a product manager at Inter-Tel, Inc., an international
provider of value-driven communications products and applications, as well
as managed services that center on voice and data network design, traffic
provisioning, custom application development, and financial solutions that
respond to todayï¿½s business needs. For more information visit
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