The introduction of optical networking into the Belgacom backbone

Fuelled by the rapid growth of broadband data traffic and the accelerated d eployment of asymmetric digital subscriber line (ADSL) technology, the Belg acom transmission network is facing an ever-increasing demand for higher ca pacities, faster provisioning times coupled with a growing rate of churn. I n order to better tackle these issues, Belgacom is deploying a new architec ture for its transmission backbone. This paper presents this new architecture, and focuses on the drivers for i ntroducing dense wavelength-division multiplexing (DWDM) technology. Wherea s the rationale for deploying DWDM in tong-distance networks is straightfor ward, it is much less so for an incumbent operator with a network involving relatively short distances, such as Belgium. The introduction of DWDM is compared with alternative solutions such as lay ing additional fibre cables coupled with the increase of transmission tine rate (STM-64/256). It is shown that DWDM offers significant advantages in t erms of better scaling the capital investments with the capacity growth, su pporting the transport of new data signals (such as gigabit Ethernet, for e xample), introducing a new level of flexibility in the network and future-p roofing the transmission backbone. The envisaged future evolution of this o ptical network is also presented.