ALPC

It means "Advanced Local Procedure Call". It seems like a light-weight RPC or if you prefer a heavy-weight LPC.

You won't find a lot of documentation on this one. Mark quickly refered to it in Inside the Windows Vista Kernel: Part 3. Microsoft has been granted a patent which infers to look for UMDF documentation. (I have to admit I still haven't read it) But the WDK is silent about this subject. It seems to be implemented in msrpc.sys (and not in the kernel like LPC). Microsoft documented references to ALPC for Event Tracing and for their new Wait Chain Traversal (which seems great).

More on this later.