(Logical Unit) In IBM SNA networking, one end of a communications session. The complete LU to LU session is defined by session type. Following are the common types. See SNA.
1 Host to 3770 RJE terminal
2 Host to 3270 mainframe terminal
3 Host to 3270 printer
6.2 Program-to-program
7 Host to 5250 midrange terminal