AbstractIn this article, we discuss the effect of architectures on behaviours and the notions of equivalence for CCS terms. Two types of architectures are considered viz, shared memory systems and distributed memory systems. Processes can be logically migrated in shared memory systems while in distributed memory systems, processes are bound to a location and require explicit migration. Communication in shared memory systems can follow the CCS principle. A complete equational characterisation of the bisimulation equivalence induced by the execution on multiprocessors requires an extended syntax; which captures the process of compiling and loading. To permit a realistic description of communication in distributed systems, asynchronous actions are required. Due to this the complete axiomatisation for the bisimulation equivalence is more sensitive to the causal structure of the processes. A practical interpretation to the complete axiomatisation of the bisimulation equivalence is also given.