Abstract
The ever increasing demand for bandwidth in computer networking has
led us from the 3Mbps Ethernet of 1976 to todays 1Gbps Ethernet. This
evolution in Ethernet bandwidth has presented the network vendors with
an increasing range of challenges when producing high capacity
Ethernet switches.
In this thesis we look at the problems related to throughput,
scalability and fairness when designing switching fabrics suitable for
Gigabit Ethernet switches. We study three different topologies, the
Butterfly, the Double Butterfly and the Hierarchical Clos together
with several routing strategies in our quest to find a viable
solution. The study is performed using two IEEE-1355 based test-beds
to build the actual topologies and do measurements.
We draw the conclusion that the Butterfly is the topology that has the
best price/performance ratio while the Double Butterfly is the winner
when price is not an issue. Universal routing is necessary to achieve
fairness in the network. This combined with grouped adaptive routing
gives us high throughput without sacrificing fairness. Finally, over
capacity in the network means a lot for the performance and
drastically reduces the differences between the different routing
schemes. When a high level of link utilization is necessary a high
degree of over capacity should be considered.