Diffserv (Dscp); Ethereal Traces; Application Thread Priorities; Codec - Nortel 1110 Fundamentals

The VLAN ID for an application must match the VLAN ID for the PC because
the PC has only one IP stack for each NIC. A second IP stack is required
to assign a specific VLAN ID tag for an application which is different than
the PC tag.
You can use two different IP cards, each with different VLAN ID values on a
single PC; however, this can cause security gaps on the voice VLAN, which
is normally a more secure network than the data VLAN.

DiffSERV (DSCP)

The IP Softphone 2050 uses DSCP settings assigned by the TPS. The IP
Softphone 2050 supports DSCP on Windows 2000 Professional, Windows
XP Pro, and Windows XP Home. For information about configuring DiffServ
values, see IP Line Fundamentals (NN43100-500).
802.1p
For information about configuring 802.1p values, see IP Line Fundamentals
(NN43100-500).

Ethereal traces

Current versions of Ethereal show 802.1Q headers, if they are present.
802.1Q must be enabled on the NIC for the headers, which includes 802.1p
to be captured.

Application thread priorities

Priorities are determined by thread priorities. The i2050QosSvc.exe
application consists of threads, which run the Graphical User Interface
(GUI) and audio threads. Thread priorities increase from the base priority
of the process, as needed. The audio threads boost to high priority, as
recommended by Microsoft, while the GUI maintains a normal priority.
Increasing the process priority implies that the operating system may not
perform properly. This concern restrains the IP Softphone 2050 to use
Windows recommended priorities to avoid an unpredictable degradation
in general OS performance.

Codec

The IP Softphone 2050 provides the following codecs:
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Copyright © 2003–2007, Nortel Networks
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G.711 provides the highest quality (if the network facilities can handle
the packet flow) because 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 Communication Server 1000
IP Phones Fundamentals
NN43001-368 01.02 Standard
Release 5.0 20 June 2007
Operation 225