A dependent local APPC LU requires the support of a mainframe in order to communicate with a remote TP. Dependent APPC LUs cannot be used to communicate with AS/400s. Unlike independent APPC LUs, dependent APPC LU only allow a single session per LU.
Dependent APPC LUs are useful when configuring SNA Server to communicate with a mainframe using a version of VTAM earlier than V3R2, since independent LUs are not supported in earlier VTAM versions. Support for dependent APPC LUs is provided with SNA Server for compatibility with older VTAM versions. If possible, independent LUs should be used.
When configuring APPC dependent LUs, you should specify the network name and LU name, even though they are not required, because they are used by software running on the SNA Server computer, such as the Windows NT Event Log. For example, if a remote APPC LU will be partnered with a dependent local APPC LU, naming the remote APPC LU helps to identify any events associated with the LU in the Windows NT Event Log.