Quality Of Service Evaluation Process Overview - Nortel Remote Office 9150 Installation And Administration Manual

March 2000
Quality of Service evaluation process
overview
Introduction
There are two main objectives when working with the QoS issue in a Remote
Office network:
to predict the expected QoS
to evaluate the QoS after integrating Remote Office traffic into the intranet
The process for either case is similar. One case is without Remote Office traffic.
The other case is with Remote Office traffic.
To evaluate the Quality of Service
It is assumed that the ping command is available on a Windows PC, or that a
network management tool provides the ability to collect delay and loss data.
1 Use ping or an equivalent tool to collect round-trip delay (in ms) and loss (in
%) data.
2
Divide the delay by 2 to approximate one-way delay, and add 93 ms to
adjust for Remote Office processing and buffering time.
3 Refer to the "Quality of Service levels" table on page 394 to predict the QoS
categories (excellent, good, fair, or poor).
4 If you want to manage the QoS in a more detailed fashion, you can
rebalance the values of delay compared to loss by adjusting Remote Office
system parameters, such as preferred codec, payload size, routing
algorithm, and so on, to move resulting QoS among different categories.
5 If the QoS objective is met, repeat the process periodically to make sure the
required QoS is maintained.
Installation and Administration Guide
Network engineering guidelines
393