  Pervasive computing appears like a new computing era based on networks of
objects and devices evolving in a real world, radically different from
distributed computing, based on networks of computers and data storages.
Contrary to most context-aware approaches, we work on the assumption that
pervasive software must be able to deal with a dynamic software environment
before processing contextual data. After demonstrating that SOA (Service
oriented Architecture) and its numerous principles are well adapted for
pervasive computing, we present our extended SOA model for pervasive computing,
called Service Lightweight Component Architecture (SLCA). SLCA presents various
additional principles to meet completely pervasive software constraints:
software infrastructure based on services for devices, local orchestrations
based on lightweight component architecture and finally encapsulation of those
orchestrations into composite services to address distributed composition of
services. We present a sample application of the overall approach as well as
some relevant measures about SLCA performances.
