Nortel Meridian ITG Line 2.0 Description, Installation And Operation Manual page 81

DiffServ/TOS
The Type of Service (TOS) byte or Differentiated Service (DiffServ) code
point determines the priorities of the management and voice packets in the
ITG network. The range for both management and voice packet
DiffServ/TOS is 0-255.
You can configure the DiffServ/TOS value, if required, to obtain better QOS
over the IP data network (LAN/WAN).
The value entered depends on the policy in the customer's data network.
Note: The default value for both is 0. Do not change DiffServ/TOS from
default value of 0 unless instructed by the ITG network administrator.
Loss and Level Plan
The ITG Line 2.0 card ships with a predefined loss and level plan. The loss
and level plan determines various parameters, such as transmission gain, that
vary from country to country. The values are stored in a file on the
MAT 6.6/OTM 1.0 PC. The default loss and level plan is for the United
States. You can select other countries when you configure the DSP Profile
settings in the MAT 6.6/OTM 1.0 ITG IP Phones application.
Echo canceller
The echo canceller tail delay is 8, 16 or 32 ms. The default setting is 32 ms.
The voice activity detection is -20 to +10 dB. The default setting is -17. The
default setting is "Enable echo canceller". You can disable echo canceller
when you configure the DSP Profile settings in the MAT 6.6/OTM 1.0 ITG
IP Phones application.
Reducing delays
The link delay is the time it takes for a voice packet to be queued on the
transmission buffer of a link until it is received at the next hop router. Link
delay can be reduced by:
• upgrading link capacity. This reduces the serialization delay of the
packet, but also reduces the utilization of the link and the queueing delay.
Before upgrading a link the technician must check both routers
connected to the link to be upgraded and make sure that router
configuration guidelines are complied with.
• implementing a priority queueing discipline.
ITG Line 2.0/i2004 Internet Telephone Description, Installation, and Operation
IP Network engineering guidelines Page 81 of 302