Lu

In the IBM Systems Network Architecture (SNA), a program that manages communications software for communications with end users. A logical unit session originally was defined as an end-to-end communication between an end-user terminal and the originating application residing in the host. Later versions, such as LU 6.2, support peer-to-peer communications between intelligent devices, without requiring the host to assume responsibility for communications support activities. LU 6.2 is also known as Advanced Program-to-Program Communications (APPC).