Nortel 1110 Fundamentals page 222

222 Nortel IP Softphone 2050
However, the IP Softphone 2050 is an application within the context of
the PC operating system, so the operating system has an effect on
the end-to-end QoS for the IP Softphone 2050. Functionality, which is
commonly handled in DSP hardware (such as, the codec packetization
implementation from within the Voice Gateway Media Card) is implemented
in software for the IP Softphone 2050. It runs as part of the application
code on the PC CPU. If the CPU is busy with other tasks, voice quality
can be negatively affected.
The number of buffers used to buffer audio data between the application
and PC audio hardware device driver is adjustable from the Settings >
Sound Devices window. Using fewer buffers reduces the audio path delay
but increases the chances of dropouts and choppy speech, depending on
the speed and utilization of the PC CPU.
This system-wide registry key setting affects other applications and
operating system components but is only effective if Windows QoS Packet
Scheduler is installed. For more information about Windows QoS Packet
Scheduler, see
For Windows 2000 the Windows QoS Packet Scheduler is not installed by
default and the EnablePriorityBoost registry setting is not created.
For Windows XP the Windows QoS Packet Scheduler is installed by default
and the EnablePriorityBoost registry setting is created. The default setting
is 1 (enable QoS).
Windows 2000 and Windows XP require a system-wide registry key to
enable QoS capabilities. You must have Administrator privileges to create or
modify the following value:
HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/Services/Qossp/
EnablePriorityBoost
Value 0—do not enable QoS
Value1—enable QoS
Trace utilities can be used to verify QoS settings. See
(page
QoS settings
The IP Softphone Version 1 includes a QoS tab in the Configuration utility.
You can enable or disable 802.1Q/p settings. The QoS tab provides the
following settings:
•
•
Copyright © 2003–2007, Nortel Networks
.
"Windows QoS Packet Scheduler" (page
224).
Enable—sends 802.1Q/p whether it is supported by the network or not
Disable—does not send 802.1Q/p whether it is supported by the
network or not
Nortel Communication Server 1000
IP Phones Fundamentals
NN43001-368 02.01 Standard
Release 5.0 7 December 2007
238).
"Ethereal traces"