Articles

Semaphore to… DWDM

We asked our technical expert Mike Stamp to provide a simple update on buzzwords… This time it’s Dense Wave-Division Multiplexing (DWDM).

Optical fibres

Commercial optical fibres were introduced in the early 1990s. Data is transmitted by shining a light down a long, thin, piece of glass. Optical fibre brought a massive increase in the volume of data that can be carried by a single communications link - one hundred thousand concurrent telephone calls could now be supported on a single fibre.

The standard data rate down a single fibre nowadays is 2.5Gbps (that’s 1,000 megabits or a billion bits per second!).

So what’s the wave division?

Most optical fibres currently use only one infrared light signal of a particular wavelength, or ‘colour’. The next step is to use multiple light sources (in practice lasers) of different wavelengths on a single fibre.

Each ‘colour’ is the same as a single fibre using one colour. Existing multiplexers use up to 64 wavelengths, greatly reducing the number and cost of fibre links.

…and dense?

The international DWDM standard defines 300 standard wavelengths at 50GHz spacing (for those of a technical bent …. the frequency of infra-red light is around 200,000GHz, so 50GHz separation is easy.)

When full exploitation is achieved, a single fibre pair will provide 750Gbps… and you can get 144 pairs of fibres in a single ‘trunk cable’. That’s about 100,000Gbps - enough to support the Earth’s entire population on the phone at the same time.

New Chaucer Consulting masterclass

As many of you know, ItemPlus runs masterclasses in programme management, portfolio management, benefits management and supplier selection.

We are assembling a new masterclass on supplier management focusing on:

  • Supplier performance assessment - running a periodic review of BPO suppliers
  • Supplier relationship management - the mechanisms of working with suppliers in the build/run phases
  • Improving Productivity, Quality and Service of the supplier
  • Retained organisation design - the key components (people, activities) that have to be retained (or built).

We are planning to run the first event on 22nd March 2007.