NC1703

OPINION
CONTROLLING
BORDERS TODAY
WITH PLANS FOR ITS DEMISE,
WHAT IS THE FIRST STEP IN
REPLACING ISDN? KEVIN
BAYNES, COUNTRY MANAGER
AT SONUS, SAYS THE SUNSET
FOR ISDN IS THE SUNRISE FOR
SIP TRUNKING
In 2015, BT announced that it would switch
off its UK integrated services digital
network (ISDN) by 2025, reflecting the
increasing number of businesses outgrowing
their current communications networks. This
clearly will swiftly reduce the number of
available ISDN channels. While ISDN is a
robust and reliable technology, it doesn't offer
the functionality, flexibility and ROI of Session
Initiation Protocol (SIP) Trunking. But
increased functionality is not the only reason
why organisations should consider SIP. BT's
announcement means that it will cease
investment in ISDN which will then become
an unsupported legacy technology.
THE SIP BENEFITS
SIP trunking consolidates voice, video and
data onto the same service provider's pipe
along with one monthly bill. Enterprises
unifying voice, video and data onto a SIP
trunk will reduce their data centre headaches
because as they grow, the infrastructure to
handle additional voice and data traffic
resides in the same place.
Adding SIP based services is very different
from that of PRI or BRI connections replete
with up to 90-day lead times. With SIP trunks,
providers can add bandwidth in hours, not
days. SIP also enables enterprises to
centralise and deploy applications, like
Unified Communications from a single server
across their entire enterprise network.
Combine SIP with a Session Border
Controller (SBC) and IT managers can
centrally manage things such as dial plans,
compliance recording as well as billing and
cost accounting records.
Traditionally, phone numbers are tied to a
building address whereas SIP numbers are
location independent. You may be in London
but you can make and receive calls using a
Birmingham number, and should a local or
regional event take you offline, calls can
automatically flow through other gateways
without service interruption. Branch offices
can also provide support during busy hours.
Simply put, SIP's simplified architecture allows
enterprises to reduce costs, rapidly deploy
new applications and solutions, and
seamlessly grow with demand.
THE ROLE OF SBC
Care should be exercised when choosing a
SIP provider. First, be sure to read the fine
print in the service level agreement so that
you clearly understand what you will get in
terms of network uptime, call completion
rates and quality score. Next, be sure to
deploy a SBC, which for SIP-based
communications is paramount. Traditional
firewalls provide security for IP-based data
sessions but are not built to deal with the
real-time nature of SIP traffic. SBCs prevent
communication-based denial of service (DoS)
attacks while supporting security features such
as topology hiding, encryption and more.
Keeping SIP secure is an important reason to
invest in an SBC, but an SBC performs several
other valuable functions including interworking
between UC systems, SIP implementations,
legacy phone networks and different codecs.
For example, if your network deploys more
than one vendor's UC implementation,
perhaps from a merger or acquisition, an SBC
will help the different UC implementations to
communicate with each other.
Similarly, an SBC provides interworking
between different signalling systems, such
as legacy telephone networks and IP-based
PBXs. That's crucial if you want to sweat
your investment in legacy systems. SBCs
can also save money by helping to choose
the most effective, least-cost route for
sessions over a network.
PLAN FOR THE FUTURE - DON'T WAIT
FOR THE END…
With ISDN moving off into the sunset, it
makes sense to deploy a SBC today so your
organisation is ready for SIP Trunking
tomorrow. You'll save money from the outset
and invest in the future of communications.
An SBC will simplify your migration to SIP
so that when your business is ready to
move, everything you require will already
be in place. Until then you can keep your
ISDN as backup. NC
26 NETWORKcomputing MARCH/APRIL 2017 @NCMagAndAwards
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