BELGACOM Forum 523, Руководство по монтажу и пусконаладке, Страница: 117 / 244

Media Gateway (MGW) 115
Voice over IP (VoIP)
Media Gateway (MGW)
The Media Gateway transforms VoIP voice data into PCM audio
data. This function converts voice data between VoIP telephones
and all other terminal types. Without the Media Gateway, VoIP tel-
ephones can only exchange call data directly with other VoIP tele-
phones. Media Gateway functionality is also required for produc-
ing dial tones and making external phone calls with a VoIP
telephone.
A Media gateway card makes 8 channels available. One Media
gateway channel should be available for a maximum of 3 VoIP ter-
minals. The Media Gateway also takes over the routing function
for external SIP connections, making 8 external SIP connections
possible.
Software MGW
The system software for Forum 523/524 provides a Media Gate-
way function. Depending on the system processor utilisation and
available system memory up to 32 MGW additional channels may
be available.
The Media Gateway function provided by the system software has
the following features:
z
Up to 32 channels can be used simultaneously.
z
The MGW channels are not compressed, so only the G.711
codec is available.
z
There is no echo suppression.
z
Voice quality may be reduced during high system utilisation.
z
Q.SIG-IP, DECT over IP and SIP are not possible.
For optimal call quality and high availability, you should consider
using a MGW interface card (see also
MGW Interface Card starting
on page 116).
The Media Gateway function (“Software MGW”) is used preferably
for connections with the G.711 codec - even if a MGW interface
card is installed.