This paper provides three contributions to research on pluggable protocols frameworks for performance-sensitive distributed object computing (DOC) middleware. First, we outline the key design challenges faced by pluggable protocols developers. Second, we describe how we resolved these challenges by developing a pluggable protocols framework for TAO, which is our high-performance, real-time CORBA-compliant ORB. Third, we present the results of benchmarks that pinpoint the impact of TAO’s pluggable protocols framework on its end-to-end efficiency and predictability.

Our results demonstrate how the application of optimizations and patterns to DOC middleware can yield both highly flexible/reusable designs and highly efficient/predictable implementations. In particular, the overall roundtrip latency of a TAO two-way method invocation using the standard inter-ORB protocol and using a commercial, off-the-self Pentium II Xeon 400 MHz workstation running in loopback mode is ∼189 µsecs. The ORB middleware accounts for approximately 48% or ∼90 µsecs of the total roundtrip latency. Using the specialized POSIX local IPC protocol reduces roundtrip latency to ∼125 µsecs. These results illustrate that (1) DOC middleware performance is largely an implementation detail and (2) the next-generation of optimized, standards-based CORBA middleware can replace ad hoc and proprietary solutions.