Bandwidth Requirements; Interoperability; Voip Solutions; Routers - Multitech VoIP User Manual

Bandwidth Requirements

One common misconception about VOIP is that it is a
bandwidth hog, when, in fact, voice is a very efficient type
of traffic. Voice compression standards like G.729 (8:1)
and G.723 (10:1) are used to minimize the bandwidth
required for voice. G.723, for instance, is the maximum
compression rate and requires only 5.3K bps (plus an
added 7-8K bps for IP overhead). Even at maximum
compression, your VOIP solution will still provide near
toll-quality voice.
As a rule of thumb, 14K bps of bandwidth per call is ideal.
This includes the compressed voice packet and the IP
overhead. To determine total VOIP bandwidth needed per
location, take the number of VOIP channels being used
and multiply by 14K bps. Then double this number to
accommodate for both voice and data traffic.
It should also be noted that bandwidth is used only when
someone is speaking. A silence suppression/Voice
Activation Detection (VAD) feature is an option that frees
unused call bandwidth for data traffic. This is significant,
since callers are usually silent for 60 percent of the call.

Interoperability

Standards are still emerging that ensure VOIP features
work with different vendor solutions. The H.323 standard
is the one most widely deployed and is the only approved
protocol adopted by the International Telecommunications
Union (ITU). The H.323 standard provides support for
audio calls to other H.323 clients, gateways, gatekeepers
and conference servers. Another emerging standard is the
Session Initiation Protocol, or SIP. Look for products that
are adopting these two standards.

VOIP Solutions

From the wide variety of VOIP solutions available today, the
one you select depends on the size of your business, the level
of networking expertise available, the amount of
integration with legacy equipment, and the level of voice
quality you require.

Routers

Router solutions usually replace an existing network
router and keep voice and data all in a single box.
However, this solution requires networking expertise, and
can be costly to install, while placing network services at
risk during deployment and maintenance.
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