I'm trying to get my head around AMQP. It looks great for inter-machine (cluster, LAN, WAN) communication between applications but I'm not sure if it is suitable (in architectural, and current implementation terms) for use as a software bus within one machine. Would it be worth pulling out a current high performance message passing framework to replace it with AMQP, or is this falling into the same trap as RPC by blurring the distinction between local and non-local communication? I'm also wary of the performance impacts of using a WAN technology for intra-machine communications, although this may be more of an implementation concern than architecture. War stories would be appreciated.