Abstract
Switched Ethernet is a dominating technology in local area networks,
and a strong contender in system area networks.
This thesis describes measurements on switched Ethernets, in the
context of high speed system area networks with real time
requirements. One such system is the ATLAS level 2 trigger, which
formed the basis of the measurements. Further on the thesis
describes the design, implementation and results from a simulation
model of the measured devices.
In general the results indicate that switched Ethernet
provides a service close to the ideal for this switch architecture.
The devices were found to be near non-blocking and it was possible
to prevent packet loss with Ethernet flow control. Some performance
anomalies were found, and the thesis emphasises that validation tests
are needed in this application since it is beyond normal usage
patterns for these commodity products.
A simulation model of the network was developed. It was possible to
obtain a quite accurate model of the latency distributions. Packet
loss proved to be difficult to model accurately. The lack of a head
of line blocking prevention mechanism in the model is thought to be
the reason for the packet loss inaccuracies.