network performance and QoS parameters can be : active monitoring, passive
monitoring and using standard management protocols like SNMP. A service
class can be mapped to many NPM. This mapping depends on the type of
services and can be very complicated. And the quality information of service
should be presented in customer friendly form, not NPMs. Therefore it is
necessary to translate the measured NPMs to SLA parameter.
In this report, SLA is used interchangeably with QoS parameters at the
application layer. And the QoS parameters at the network level is used
interchangeably same as NPMs (network performance metrics).
1.2
Quality of Service (QoS)
As said in [1], QoS is a vaguely defined term. But, here in our context,we are
defining QoS as a 'predictable traffic quality' that satisfies following criterion:
1. Delay
2. Jitter
3. Packet loss percentage
4. Throughput
Delay ensures the maximum delay bound that is acceptable to the ap-
plication. Jitter reflects variation in delay and is important for real time
applications. Packet loss probability shows the probability of the packet
loss. Throughput is the data rate that the system can transfer. This is an
important factor in streaming applications.
3