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COMMUNICATIONS
20
Why VoIP over VDSL is bad
for business
unable to receive a business quality
telephone service with a consequent
materially adverse effect on their trading
ability. VoIP over VDSL is a significant
potential risk to UK business.”
Lower priority
The whitepaper points out that network
usage is constantly growing, so the
problem is only likely to get worse. At the
moment, for example, priority over the
public internet is given to streaming the
explosive growth of digital TV services, such
as Amazon Prime, NOW TV and Netflix.
Other traffic may have to take lower priority
as a result. With take-up of such services
increasing, VDSL VoIP users should expect
a deteriorating service.
So what should customers choose
instead?
Spitfire offers customers its own Voice
Approved Broadband circuits for VoIP SIP
trunks. These ensure end-to-end call QoS,
with guarantees on Latency, Jitter and
Delay, both upstream and downstream.
These guarantees are not available on
VDSL broadband services.
As one of the few ISPs and fixed line
operators to offer a SIP trunk service,
Spitfire provides a complete end-to-
end SIP service via its own IP and TDM
infrastructure.
Graham Lewis, Spitfire Director IP
Engineering and author of
The Truth
about VDSL and VoIP
, said: “At Spitfire
we discourage the use of VDSL for voice
because, whilst anecdotally many people
have found it ‘good enough’, it offers no
guarantees of voice quality or any route
to resolution should voice quality become
unacceptable. Our reassurance of an end-
to-end service with QoS guarantees has
been a key factor in the success of Spitfire
SIP trunks for VoIP.”
The whitepaper, entitled
The Truth about
VDSL and VoIP
, examines the issues
surrounding the use of VDSL circuits for
voice over IP services.
VDSL (Very High Speed Digital
Subscriber Line) or Fibre Broadband
is widely established in the UK and is
increasingly being used by businesses for
high speed Internet access with download
speeds of up to 80Mbps.
However, a broadband circuit optimised
for Internet browsing is not necessarily the
best choice for VoIP.
No guarantees
Although call quality on VDSL circuits
may currently be acceptable, Spitfire
discourages the use of VDSL technology
for voice because it offers no guarantees
of voice quality or any route to
resolution should voice quality become
unacceptable.
Spitfire explains that to give
satisfactory voice quality, a circuit must
deliver:
n
a maximum latency of 150ms end-to-
end (mouth-to-ear);
n
packet loss of less than 1%; and
n
jitter of less than 45ms.
While these technical requirements may
be met on a VDSL service most of the
time, there is no guarantee that they will
be met all or even some of the time.
Long lead times
Users wanting to upgrade to Ethernet
connectivity for VoIP can be faced with
deployment lead times of up to a year for
Ethernet circuits. Poor quality voice calls
in the interim could reflect badly on a
business and damage its reputation.
Harry Bowlby, Spitfire’s Joint Managing
Director, said: “Businesses that choose
a VoIP solution without appropriate QoS
guarantees are gambling with their future.
Should voice quality issues arise, they
may find that an acceptable solution is
unavailable or takes an unacceptable
period of time to deliver, leaving them
Businesses that
choose a VoIP
solution without
appropriate QoS
guarantees are
gambling with
their future
VoIP over VDSL could spell disaster for UK businesses, warns Spitfire in its latest whitepaper.
Harry Bowlby
Joint Managing Director
Spitfire
To download a copy of the whitepaper and find out about these issues in more detail,
please visit
