ASCOM Ascotel AIP 6350, Системное руководство

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AIP 6350 / Office 35IP
Network Environment 41
6.1.2 Bandwidth Management
The available bandwidth can be limited, especially on WAN links. The bandwidth
control of AIP 6350 prevents call connections from being set up if there is too little
bandwidth available (see "Bandwidth Control", page 43). The following methods
help to reduce the bandwidth requirement:
• Voice compression:
In the LAN area with sufficient bandwidth it makes sense to use a codec with-
out compression (G.711) as the speech quality is better. Compressing codecs
are used to advantage in WAN areas with limited bandwidth. See the Chapter
"Bandwidth Control", page 43.
• Compressing the IP header:
Voice packets are relatively small compared with their header (large overhead).
On a point-to-point connection between 2 routers the 40 byte header can be
considerably compressed. This means the resources of the available bandwidth
can be used more sparingly. This setting is carried out in the router. Possible
method: cRTP.
6.1.3 Security
Uncoded phone calls in the network can be recorded and played back using the
appropriate equipment. For this reason it is preferable to use your own leased
lines for WAN links or to encode the IP packets using for example VPN (Virtual Pri-
vate Network).
For the port configuration of the firewall see the Chapter "Applications, Protocols
and Ports", page 53.