Page 186 of 910 Features
553-3001-365 Standard 4.00 August 2005
Bandwidth requirements
The use of IP Call Recording doubles the bandwidth requirements of the call.
For example, in a call using the G.711 codec, one voice packet data stream
requires approximately 80 kbps. As the IP Call Recorder uses two separate
streams for the in/out calls, there are four streams requiring a total of 320 kbps
for the voice packet data. In a typical 100 Mbps LAN network environment,
if 80% of the bandwidth was configured for voice data, then this network
could support a maximum of 500 simultaneous IP Phone calls.
(100 x 1000 x 0.8 / 160) = 500
When the IP Call Recording feature is enabled, that same network is limited
to a maximum of 250 calls.
For remote users connecting to the IP Call Recorder Server through a WAN
connection, the impact of the bandwidth usage to the QoS should be
considered. In this case, the IP Call Recorder Server must provide the QoS
parameters when instructing the IP Phone to echo the voice data.
Depending on the IP Call Recorder Server’s ability to handle the RTP stream,
more than one IP Call Recorder Server can be required in a large call center
environment. Middleware (software that connects two sides of an application
and passes data between them) should have an algorithm to balance the traffic
between the different servers.
Feature interactions
Mute key
When the Mute key is pressed, the IP Phone keeps both the primary and the
duplicate audio stream open. When Mute is pressed, the recording state
remains active, but only the incoming conversation is recorded. Pressing the
Mute key a second time resumes normal recording.