The dependent LU server (DLUS) function of VTAM® facilitates conversion from a subarea environment to an APPN environment, allowing you to maintain central management of remote dependent LUs while benefiting from APPN throughout a network.

Figure 1. VTAM functioning as a dependent LU server

Two LU 6.2 sessions (one inbound, one outbound) are established between a dependent LU server (DLUS) node (an APPN network node) and a dependent LU requester (DLUR) node (an APPN end node or network node that owns dependent LUs). These LU 6.2 sessions are collectively known as the CPSVRMGR pipe. The CPSVRMGR pipe sessions must be established over APPN and VRTG links only.

SSCP-PU and SSCP-LU session flows use the CPSVRMGR pipe. An SSCP-PU session is established between the DLUS node and the dependent LU's owning PU, and an SSCP-LU session is established between the DLUS node and the dependent LU. Session initiation flows for the dependent LU are sent over the SSCP-LU session, and VTAM can use subarea or APPN flows to initiate the LU-LU session.

Figure 1 shows an example of a nonadjacent DLUS-DLUR configuration.