Design and Qualification of the Interconnect for a High-Performance Modular 10Gigabit Ethernet Switch

The 10 Gigabit Ethernet standard, IEEE802.3ae, was adopted in 2002 and represented a ten-fold increase in performance over the previous 1Gigabit standard IEEE 802.3z. The standard itself covers only the details of the individual point-to-point links and does not address any system issues of how Ethernet switches may be built or deployed. Designing a switched system involves choosing an appropriate architecture, selecting the best available silicon technology and determining suitable electronic packaging. The EU funded ESTA project was established to perform the basic research and development that would define the specifications for building an Ethernet switch to meet 10Gbps switching requirements. The part of the project carried out at CERN, within which this thesis work was done, involved the development, construction and validation of the backplane support for this 10Gbps Ethernet switch. In addition the program required that there be developed an understanding of where the limits of performance lay in terms of materials, manufacture and packaging technologies. The most performant switches are built in a modular form consisting of a chassis and a number of plug-in modules. These modules plug into a common backplane which provides power, control, management and data interconnects. The functionality of such a system depends critically on the underlying interconnect even for such relatively low speed applications such as VME or Gigabit Ethernet. The backplane constitutes one of the weakest links of switching systems because it is subject to bandwidth limitations due to a limited number of connections and is also the source of signal degradation in the forms of amplitude and frequency loss, crosstalk, noise and reflections. To meet the project requirements it would be necessary to systematically identify and quantify each aspect of the design process. This had to be done in terms of the effects on the system and its performance at 10Gbps as well for higher speeds. In addition to the theoretical study there was also going to have to be a practical method developed that would show that the required performance was not only met but exceeded. This was necessary to validate to what extend the theory converged with practice and also to ensure that the final constructed backplane was free from any possible system errors when running under maximum design conditions.