Figure 1 through Figure 3 show the flow of requests and responses between the SSCP and logical and physical units to handle error recovery processing (ERP) and route Forward and Deliver RUs. Figure 4 through Figure 6 show the requests and responses between the NetView® program, VTAM®, the communications adapter, and the local modem for LPDA-2 processing. Figure 7 through Figure 10 show the flow of requests and responses between the SSCP and logical and physical units to handle extended recovery facility (XRF) session establishments and takeovers with USERVARs.