U

User Datagram Protocol (UDP)
A network transport that uses connectionless datagram sockets and is layered on top of IP.
unbind
In RPC, to terminate the logical connection between a client and server.
unique pointer
In RPC, a pointer that can be null or point to existing data and whose value can change during a remote procedure call. A unique pointer cannot be aliased. The unique attribute designates a unique pointer. See also full pointer, reference pointer.
Universal Unique Identifier (UUID)
(or GUID) A 128-bit value used in cross-process communication to identify entities such as client and server interfaces, manager entry-point vectors, and RPC objects. See also uuidgen.
uuidgen
A utility program, provided with the Win32 SDK, that uses a time value and your machine's network card ID to generate UUIDs that are guaranteed to be unique.