Detail

Stheno, a Real-Time Fault-Tolerant P2P Middleware Platform for Light-Train Systems

Large scale information systems, such as public information systems
for light-train/metro networks, must be able to fulfill
contractualized Service Level Agreements (SLAs) in terms of end-to-end
latencies and jitter, even in the presence of faults. Failure to do so
has potential legal and financial implications for the software
developers. Current middleware solutions have a hard time coping with
these demands due, fundamentally, to a lack of adequate, simultaneous,
support for fault-tolerance (FT) and real-time (RT) tasks. In this
paper we present Stheno, a general purpose peer-to- peer (P2P)
middleware system that builds on previous work from TAO and MEAD to
provide: (a) configurable, transparent, FT support by taking
advantage of the P2P layer topology awareness to efficiently implement
Common Of The Shelf (COTS) replication algorithms and replica
management strategies, and; (b) kernel-level resource reservation
integrated with well-known threading strategies based on priorities to
provide more robust support for soft real-time tasks. An evaluation of
the first (unoptimized) prototype for the middleware shows that Stheno
is able to match and often greatly exceed the SLA agreements provided
by our target system, the light-train/metro information system
developed and maintained by EFACEC, and currently deployed at multiple
cities in Europe and Brazil.