VoIP QoS
With all the good news surrounding VoIP, it's important
to understand an important difference in VoIP QoS (Quality
of Service) offered by providers. There may be many
VoIP providers, but not all of them will be able to
provide a level of service that will match your current
phone service. Part of the problem is there are essentially
a couple different approaches to VoIP QoS.
One approach is similar to a car navigating through
rush hour traffic. There are lots of stops and starts
and the vehicle never seems to arrive at its destination
on time. In the world of VoIP, this traffic jam is caused
by the voice packets associated with VoIP being routed
around a variety of web traffic causing gaps between
the time a message is spoken and when it is actually
heard which can cause a great deal of frustration for
those involved in the conversation.
Consumers usually talk over a public network where
VoIP QoS is not guaranteed since there are too many
variables over the many different networks that are
outside the control of most service providers. Many
businesses, however, have turned to private networks
where there are more controls over VoIP QoS and thus
higher quality voice transmission and reception can
be attained.
The main components that need to be addressed by the
business VoIP service provider for satisfactory VoIP
QoS include throughput, availability, delay, delay variation
and loss. Issues such as the bandwidth between two network
points and the delays or loss of packets sent have to
be accounted for and resolved in an optimal fashion
in order for clear audio communications to occur.
Some of delay components of VoIP QoS include packetization
delay, coder delay, serialization delay, WAN delay,
dejitter delay and output queuing. Each of these delays
must be address by the network engineering team in order
to achieve satisfactory VoIP QoS from the customer perspective.
Another approach to Quality of Service (QoS) issues
is to provide either resource reservation or a private
network. The first issue is cost effective in infrequent
usage. Resource Reservation Protocol (RSVP) allows ends
systems to request VoIP QoS guarantees from a network.
The second is the better long-term solution for businesses
because it provides a system dedicated to handling voice
traffic only. In either scenario, the result is a service
that is very similar to existing phone systems with
quality audio and response time.
VoIP has had a growing number of subscribers and the
reasons are many. In fact, many phone service providers
are looking at a move from landlines to VoIP as a means
of retaining customers and eliminating aging infrastructure.
As for VoIP QoS, issues, computer networks are not an
exact science. Technicians need to continue to tweak
the minor delays and explore new VoIP QoS methodology
and systems in order to achieve the highest voice quality.
When visiting with a business VoIP provider, be sure
to ask if the service is provided through DSL or a private
network. The answer to this question will be crucial
in determining if the end-result of your phone search
will be a positive experience. The correct response
will be private network since DSL latency is still too
unpredictable for business VoIP. Also find out if the
provider is peered with the largest IP networks such
as Level 3, Savvis or UUNet. This will let you know
if they are serious about VoIP QoS or a provider that
thinks of quality as just an afterthought.
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