Enclosure for multi-processor equipment

A rack-mountable enclosure (100) includes an interconnection backplane (190) for the mounting and interconnection of a plurality of horizontal, hot-swappable processing modules (150, 160) and at least one interface module (200). The interface module is arranged to provide a plurality of external connectors and to transport signals via the backplane between each external connection and an individual processing module. The backplane provides locations (F1-F8) for said processing modules to lie horizontally across a major portion of the backplane area facing a front side of the enclosure. The backplane provides a location (B1) for said interface module (200) over a minor portion of the backplane area facing a rear side of the enclosure, so as to provide said external connectors at the rear of the enclosure. A power supply module (420) is positioned over another portion of the backplane area, on the same side as the interface module. Adjacent pairs of processing modules (150-160) are linked by independent compact PCI buses. A specific application is in monitoring of broadband telecommunication networks. The location of the power supply module behind the backplane saves height and/or width in the rack.