special feature
data centres
whether external or internal – will act as a central data and application repository.
The need for speed Set against this consolidation and centralisation background, the physical IT infrastructure within the data centre becomes critical as never before. Faster speeds, increased reliability, flexibility and scalability are all important attributes to be demanded of the servers, storage and networks to be found within a data centre. But speed is king.
Diagram1: Data centre cabling structure.
Diagram 2:
OM3: the legacy multimode FO solution for 10 Gigabit Ethernet technology
migration from LED to laser sources.
has created huge demand for fast and reliable hosting and transfer of text, voice, picture and video data. Internet TV is in its infancy, but promises to grow at a phenomenal rate over the next few years, as will video-on-demand traffic. And then there’s the whole world of mobile data traffic – with video, and HD video, again predicted to grow quickly. The sheer quantity of consumer IP traffic, with the attendant need for as near real time speeds as possible, could create a serious bottleneck in the data centre. In the business world, there are similar drivers – increasing quantities of data created, that require to be stored, retrieved and served as fast as possible across the globe. Videoconferencing and HD videoconferencing will have a significant impact on business IP traffic levels moving forward, quite apart from the natural growth in traffic levels as more and more business is conducted via the Internet.
In the cloud
Underlying all of these IP traffic drivers is the increasing trend towards consolidation and centralisation. In the consumer world, over time, less and less individuals will own their own copies of songs, films, video clips and the like, but will simply access what they want to listen to or watch, when they want, via a centralised service provider.
For businesses, a similar consolidation process has been taking place over the last few years. Less and less information and applications, IT hardware even, are held at a company’s satellite, regional or branch offices. The trend has been to consolidate, or centralise, the IT function into one or two data centres, with attendant back up facilities to provide the required level of business continuity. Cloud computing accelerates this centralisation process still further – in both the consumer and business environments. Service providers –
In the storage world, Fibre Channel has for long been the dominant connectivity protocol, joined in more recent years by IP, or iSCSI, technology. Fibre Channel provides deterministic, low latency and high speed communications between servers and storage systems via optical fibre cabling; iSCSI takes advantage of the standard Ethernet protocol, used in most data centres for transmitting data from client to server or between servers.
The pure Fibre Channel roadmap already allows for speeds up to 8Gb/s, with 16Gb/s the next logical step. Meanwhile, development of Fibre Channel over Ethernet (FCoE) aims to consolidate both storage, or SAN, and Ethernet data traffic into one common network interface, enabling the same cable to be used for both. Hence talk of ‘convergence’ at the 10Gb/s point in the near future – with FCoE likely to be a leading driver for 40 Gigabit Ethernet and beyond in edge devices over the next few years.
Meanwhile, in the server world, virtualisation has meant the consolidation of more and more applications onto less and less physical servers. Suggestions are that the ratio, currently running at approximately 4:1, could grow to as much as 20:1. With so many applications running on one physical server, the increased data transmissions to and from servers will require higher bandwidth capacity. 10Gb/s server technology, followed closely by 40 Gigabit Ethernet servers, is the way forward.
Move to 40
Gigabit Ethernet With the storage and server and other edge devices moving in the direction of 10Gb/s speeds and beyond, the data centre’s core network needs to be capable of supporting much higher traffic speeds. Hence development of the 40 and 100 Gigabit Ethernet standards, designed to address short reach transmission, via parallel transmission
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