Talkswitch 24-CA - Manual (Page 168)

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5.2 OPTIMIZING YOUR IP NETWORK FOR VOIP
5.2.1 The broadband connection
Figure 122: Broadband
For optimal quality of VoIP calls on your system, we recommend that you
subscribe to a high-speed broadband connection from your service provider.
‘Lite’ broadband is not suitable for simultaneous voice and data traffic.
‘Lite’ broadband typically runs 128 Kbps downstream and 64 Kbps upstream.
The limiting factor for a broadband connection is the upstream bandwidth to
the Internet Service Provider (ISP).
Example: If you have a 1 Mbps ADSL connection from your service provider,
it likely means you have an upstream bandwidth of approximately
380 Kbps. Keep in mind that not the full 380 Kbps are available at all times.
You can estimate about half of the upstream bandwidth as being available.
In this case, you could safely support two simultaneous G.711 calls
(100 Kbps/calls) or four simultaneous G.726 calls (50 Kbps/calls) or 10
simultaneous G.729 calls without factoring in other data traffic on the
network at the same time. With additional traffic on the Internet or private
IP network, the number of simultaneous calls supported is reduced.
5.2.2 The router/NAT/firewall
Figure 123: Router
G.711, G.726 and G.729 are VoIP codecs. For more information on codecs,
see Codec Options (button) on page 167.
Internet or
Private IP
Network
Modem
xDSL
Cable
Satellite
etc.
Internet or
Private IP
Network
Modem
xDSL
Cable
Satellite
etc.
Router/NAT