  The High Level Trigger (HLT) of the future ALICE heavy-ion experiment has to
reduce its input data rate of up to 25 GB/s to at most 1.25 GB/s for output
before the data is written to permanent storage. To cope with these data rates
a large PC cluster system is being designed to scale to several 1000 nodes,
connected by a fast network. For the software that will run on these nodes a
flexible data transport and distribution software framework, described in this
thesis, has been developed. The framework consists of a set of separate
components, that can be connected via a common interface. This allows to
construct different configurations for the HLT, that are even changeable at
runtime. To ensure a fault-tolerant operation of the HLT, the framework
includes a basic fail-over mechanism that allows to replace whole nodes after a
failure. The mechanism will be further expanded in the future, utilizing the
runtime reconnection feature of the framework's component interface. To connect
cluster nodes a communication class library is used that abstracts from the
actual network technology and protocol used to retain flexibility in the
hardware choice. It contains already two working prototype versions for the TCP
protocol as well as SCI network adapters. Extensions can be added to the
library without modifications to other parts of the framework. Extensive tests
and measurements have been performed with the framework. Their results as well
as conclusions drawn from them are also presented in this thesis. Performance
tests show very promising results for the system, indicating that it can
fulfill ALICE's requirements concerning the data transport.
