This is a new namespace introduced from CLR 2.0.
How can you use this ? This namespace can be used when your client and the Remotable components are present in the same machine.
IPC stands for interprocess communications in the same windows OS.
.Net 1.1 had only TCP channel--which means the remotable components were using TCP channel for remoting , but from .Net 2.0 we have the option of deciding between IPC or TCP..
So according to your remoting requirements and if you use .Net 2.0 you can use IPC communications.