Fun Factor Characterization of User Perceived
Quality of Service for Elastic Internet Traffic
Joachim Charzinski
Abstract
Classical quality of service (QoS) measures such as packet loss probability,
delay or delay variation are available for non-elastic network traffic.
However, most of today's data traffic is transported over the
Transmission Control Protocol (TCP) in the Internet, and TCP
uses a flow control mechanism to adapt a connection's bit rate
to the resources available in the network in order to get the same
``fair share'' of bandwidth as the other TCP connections sharing
the same bottleneck link.
Recent efforts in describing elastic traffic have recalled
Processor Sharing models and tried to establish bandwidth related
QoS measures such as ``delay factors'' or ``fun factors'' to
describe the user perceived quality of service for elastic traffic
applications.
In this paper we discuss possible definitions of fun factors
as well as DNS and TCP properties that influence the
bit rates achievable with elastic traffic.
Measurement results give an indication of the
rates occurring in the Internet. They also
reveal the delays and success rates
to be expected from DNS requests, which can be a major cause
of delay in HTTP retrievals.
Keywords
Internet Traffic; TCP; User Perceived QoS; Fun Factor;
Elastic Traffic; HTTP Traffic; DNS Latency; Measurement