Kenya Data Network (KDN), a local public data carrier company, in conjunction with Siemens Communications, one of the largest players in the global telecommunications industry, is currently laying fibre optic cables around the country.

The current digging up of Nairobi's central business district is the first phase of a USD50 million national fibre optic backbone, which started three weeks ago and will run from Mombasa to Busia on the Kenya/Uganda boarder.

KDN was established in 2003 by the Sameer Group in the wake of the liberalisation of the telecommunications market in the country.

Sameer invested about USD10 million in sophisticated data communications infrastructure in July 2003 and launched commercial leased line, frame relay, and Internet protocol data services aimed at businesses and large institutions in Nairobi and around the country. The Sameer IT portfolio includes Swift Global Kenya and ICL.

The Nairobi project - also called the Metropolitan Fibre Network - will cover Upper Hill, Westlands and the central business district. The fibre ring will run from the First American Bank on Nyerere Road through Serena Hotel and will later cover the NSSF building, the Fairview Hotel, George Williamson House, Rahimtullah Towers, the British High Commission and the NHIF building.

Fibre optic is substantially cheaper than satellite communication and can carry more information. It is expected to fully integrate the country into the global broadband telenetwork.

"KDN's corporate customers are not the only ones who will benefit from the new technology. In the next stage, we intend to implement a nationwide backbone and become a carriers' carrier, providing wireless operators with the capacity for data transport," said Kai Wulff, KDN's managing director.

The network will be 35km long, running through Nairobi's business quarter, and will use Siemens Carrier Ethernet technology for access. The data transport via ethernet will allow bandwidths of up to 16x1gigabit.

"We want to give IT professionals the tools to concentrate on developing and maintaining the crucial business processes that run their networks, while we focus on maintaining the 99.9 per cent network availability that we guarantee to our customers," said Evelyn Rono, KDN's external affairs manager.

Fibre is a very pure strand of glass through which light can pass over great distances. Fibre optic cables have a fibre core made of such glass, which is used for the actual signal transmission. What surrounds the glass, to protect and buffer it, varies.

The two most common ways of protecting the fragile fibre are to enclose the fibre in a loose-fitting tube or to coat it with a tight-fitting buffer coating. Like copper wire, fibre optic cable is available in many physical variations. The application determines the type used. Both loose tube and tight-buffer constructed cables are available in single mode and multimode versions. Single mode and multimode refer to the diameter of actual glass fibre located within the "core" of the cable. More specifically, these terms refer to the number of light paths that may pass through the actual fibre.

Fibre is light and easy to handle. Fibre-optic cable therefore offers the installer a great deal of freedom and flexibility during the actual installation process. Fibre is available in a wide range of constructions, each designed to withstand certain types of environmental conditions and application challenges. In general, all fibres use less duct space and, in fact, may often be laid without ducts - simply passing between walls and flooring wherever convenient. They can also accommodate structural curves and turns, but tight bends must have a turning radius of at least one inch.

Because it is so resilient to environmental concerns, fibre is ideal for connecting systems between buildings, when a cable must be laid outside underground. In fact, if the proper type of fibre cable is used, it can be laid directly in the ground, with no concern for exposure to moisture or humidity. And, if a cable is accidentally severed, there is no risk of a spark causing fire or danger to personnel coming in contact with the severed fibre.