The SCA Control Program (SCACP) utility is designed to monitor and manage cluster communications. It is derived from the Systems Communications Architecture (SCA), which defines the communications mechanisms that allow nodes in an OpenVMS Cluster system to cooperate. SCA does the following: o Governs the sharing of data between resources at the nodes o Binds together System Applications (SYSAPs) that run on different Alpha and VAX computers Historically, LAN cluster port information has been available only in the System Dump Analyzer (SDA) utility and by using the Availability Manager management tool. The ability to start and stop PEdriver on a LAN device was provided by SYS$EXAMPLES:SYS$LAVC_START_BUS.EXE and SYS$LAVC_STOP_BUS.EXE. No way existed to prioritize use of LAN devices or individual channels. SCACP provides an alternative method of collecting cluster management data and exercising management control over cluster communications. OpenVMS Version 7.3 introduced SCACP's ability to manage SCA use of LAN paths. Beginning with OpenVMS Version 7.3- 1, you can use SCACP to manage all OpenVMS Cluster interconnects. Starting with OpenVMS Version 8.4, OpenVMS is enhanced to use IP (Internet Protocol) for cluster communications. OpenVMS cluster over IP (also referred to as IP Cluster Interconnect) is the ability to use IP stacks for cluster communications. PEdriver which implements the cluster communication protocol uses UDP (User datagram protocol). Format RUN SYS$SYSTEM:SCACP To invoke SCACP, enter the following command at the DCL prompt: $ RUN SYS$SYSTEM:SCACP SCACP displays the following prompt, at which you can enter SCACP commands using the standard rules of DCL syntax: SCACP> To exit SCACP and return to the DCL command level, enter the EXIT command at the SCACP> prompt or press Ctrl/Z.