Indirect IPC or direct IPC

[chenggh]

Hi:
	Today I read the DICE Manual 3.1.0 and it talks about something about 
indirect IPC and direct IPC.
	According to my understanding it seems like this:
	indirect IPC: sender - > message buffer -> receiver
	direct IPC: sender ->sender buffer -> receive buffer ->receiver.

	But I think this understanding is wrong and I don't search something helpful 
by google, too. If somebody knows please tell me.

	In this manaul it says ln L4 version 4 all constructed data types will be 
transmitted by indirect IPC not direct IPC. I also want to know why.

	Thank you.
	Best wishes.
									cheng