The bandwidth is growing every year between 50% and 100% depending on the switching point which is analysed. More than 10 years ago the 10 Gbit/s ETHERNET standardisation activities started and today the technology is well installed about different development steps. From serial XFP-module with Fabry-Perot Laser over optical multiplexed XENPAK-module with 4 times 3,125 Gbit/s to VCSEL-based (850 nm) modules for short distances in the equipment connections and DFB-Laser (1310 nm) and EML (1550 nm) for long distance (40 km) in all form factors. The 10 Gbit/s technologies are well installed in the server cluster of server farms (5.000 to 10.000 servers in one server farm, or depending on architecture is the equivalent of 20.000 to 40.000 10Gbit/s optical ports; e.g. Google has worldwide 5000 server farms and this are 100 million ports all types of modules).
Fig. 1 shows the bottlenecks (cubes) in the nodes of the different networks. Between 2003 and 2006 the GbE growth and the 10 GbE growth were correlated, it looked like a symbiotic relationship. In 2007 the 10GbE growth being constrained by lack of higher speed interfaces (Source: Sprint, Yahoo, EDS, Amazon, AMS-IX, Cox, NTT, Equinox).
The higher speed interfaces is depending on availability of components which allows design of low cost modules with low power consumption based on existing technology. The requirement is now according the ETHERNET now 100GbE data-transmission independent of the realisation. Fig. 2 the shows the next generation of switching nodes.