Prepare now for 40G

CXO sits down with Nexans’ Martin Rossbach to discover what next generation data centres will look like and how comprehensive migration strategies will play their part.

CXO. How important is the data centre and what should system designers take into account?
Martin Rossbach. The data centre market has been booming for over a decade and is still expanding despite the financial crisis. This shows how vital this is for major companies.  Companies going through a data centre re-design today are very concerned about energy and cooling and the design of the SAN but often do not pay enough attention to the cabling infrastructure today. The design of the network and the cabling infrastructure are often treated as two separate entities but this needs to change. Since cabling brings the whole network together they need to establish a forward looking infrastructure to cope with future needs. The design needs to be application independent and modular in order to cope with the increasing lifetime expectations of modern data centres which can be 20 years or greater.

How should the data centre ICT infrastructure be configured?
Although 'Top of Rack' switching has had some success, the need to get data in and out of the data centre as fast as possible has placed more emphasis on the need to adopt an 'End of Row' solution. Data centre networks are moving to a flatter hierarchy as opposed to a Christmas tree design so fewer switches will have less effect on latency. Top of Rack adds to the latency problem. By moving to an 'End of Row' switching solution you can also achieve connections between any two points in the network at reduced latency. This is facilitated by a cabling cross-connect which can be configured through simple patching and cuts out the need to travel through more switches. Structured cabling is a much better option than point to point, since powerful, energy hungry servers can be dispersed across the data centre and interconnected through the cross-connect reducing hotspots and balancing out power loading conditions for equipment and cooling systems. Bandwidth is another important factor. Adopting the highest copper cabling spec available will future-proof the network for many generations of ICT equipment; resulting in less disruption and cost.

What should designers consider in terms of future network speeds?
Ten Gigabits per second (10G) is today's benchmark transmission rate for large data centres. But high definition video on demand (IPTV), IO-Consolidation and server virtualisation will soon require the use of 'bigger pipes' on the network and will drive that benchmark to 40G and even 100GB in the data centre backbone. Many IT experts expect that the data centre switch/server links will likely migrate to 40G within the next five years.

What does this mean for cabling?
First of all you need to look at what is happening in the standards bodies such as IEEE to understand what developments are taking place for 40G and 100G Ethernet. The specifications for 40G over fibre are already finalised and define parallel optics using totally new connectivity. This is a paradigm shift from what people are used to, so considerable care must be taken when designing an infrastructure that will not only support legacy systems of today but also give a migration path and easy transition when upgrading to 40G. Nexans have already developed and launched a new range of fibre products for exactly this application.

Copper cabling on the other hand has yet to be fully resolved. There are standards available for 7m short reach point to point systems and if a standard becomes available for longer reach it is very like to be a balanced twisted pair solution such as CAT7a. Again both solutions use different connectivity than 10G, so good forward-looking planning is really required.

What is the best advice for companies planning a system that will need 40G capabilities in the future?
There is no point in putting in a system today that can only carry 10G with no capacity for future upgrades to 40G. The cost of replacing it (if possible, many cabling systems are left installed) would horrendous not to mention the disruption it would cause. Our advice would be to install both the Nexans copper and fibre 40G ready systems so you have this capacity from day one and the transition to 40G would be a very easy and simple retrofit of patch cords, The whole infrastructure core stays intact and does not have to be moved. This is the less disruptive option at the lowest cost.

Martin Rossbach is Director of Product Marketing and New Market Development at Nexans Cabling Solutions SA, Belgium. Rossbach has more than 17 years' experience in the IT and Telecommunications Industry, gathered in technical, sales and marketing roles within hardware vendors like Canon and Alcatel. Rossbach holds a postgraduate diploma in Management from TiasNimbas Business School.