We have a set of (ASMX but could be WCF) 64-bit web services which need to execute some 32-bit managed code (the APIs have 32-bit COM dependencies and cannot be executed in 64-bit) for processing on the same physical machine. The 64-bit web services are hosted in IIS 7.0. Note: some of the messages contain large byte arrays.
What is the most efficient way to set this up? WCF with named pipes and binary serialization of the messages?
Yes. Use Named pipes if it is all on one machine. Use binary serialization if you have large byte arrays.