Nortel 2001 Installation And Operation Manual page 155

802.1Q
The IP Softphone 2050 uses 802.1P (priority) settings assigned by the TPS.
The IP Softphone 2050 supports 802.1P on Windows 2000 Professional and
Windows XP. This requires the installation of Nortel Networks IP Softphone
2050 QoS Service. The DSCP values assigned from TPS 802.1Q operation
can be enabled or disabled from the QoS tab in the Configuration Utility. The
IP Softphone 2050 does not support VLAN's (the VLAN ID in 802.1Q).
The service can be installed from the CD-ROM. If you install the IP
Softphone 2050 with Administrators access, then this service is installed
automatically.
Codec
The IP Softphone 2050 provides the following codecs:
• G.711 provides the highest quality (if the network facilities can handle
the packet flow) since there is no compression.
• G.729A is ranked best; it has 8:1 compression but no voice activity
detection.
• G.729AB is the same as G.729A but includes voice activity detection;
while this provides the lowest average network bandwidth utilization, in
some call environments the speech quality suffers due to clipping of the
beginning of words.
Nortel Networks IP Softphone 2050
IP Phones Description, Installation, and Operation
Page 155 of 302