eTrust CA-Top Secret Security for z/OS and OS ... - SupportConnect

The SYSPLEX XCF FunctionThe SYSPLEX XCF FunctionThe XCF function within a sysplex environment allows communication betweenall systems in the sysplex. The main function is the message routing capability.Any system within the sysplex can "join" a group and send and receive messagesfrom each of the other members within the same group. For example, if systemA wanted to send a message to all other systems in the group it can do so byissuing a send message to the Coupling Facility. The Coupling Facility is thenresponsible for posting or notifying all other "joined" systems within the groupthat a message is waiting for them. Each notified system is then responsible forreceiving the message that was sent. The actions performed by the receivingsystem depend on the content of the message.eTrust CA-Top Secret and the SYSPLEX XES FunctionThe XES data-sharing feature lets you define a primary and an alternate Liststructure in the Coupling Facility.If this feature is enabled, eTrust CA-Top Secret attempts to obtain the requesteddata from the Coupling Facility before any physical I/O is performed. If therequested data is obtained from the Coupling Facility no I/O is performed. Thussaving the time from having to do the actual I/O to the database. If you areusing the CACHE facility with eTrust CA-Top Secret, the cache call is performedprior to any call to the Coupling Facility. If the data is found in the CACHE, nocalls to the Coupling Facility or the I/O to the database are performed.Whenever direct physical I/O is requested to the eTrust CA-Top Secret database,a number of decisions must be made. It is important that any updating of anyrecord is reflected on the database prior to the Coupling Facility. Most importantis the need to obtain the data from the Coupling Facility when a direct READ of arecord is requested. If any record is being updated, a lock to the CouplingFacility is issued to prevent the same record from being updated in the CouplingFacility by another eTrust CA-Top Secret system. The Security File ENQ recordshows which system is currently holding the lock and a time stamp indicates thetime the lock was placed.A List structure allows eTrust CA-Top Secret to optimally control what is placedin the Coupling Facility and the maintenance of the data once it is there. Theprimary List structure, defined by the systems programmer, is used to hold allthe data for the eTrust CA-Top Secret database. The optional alternate Liststructure is used in the case that something happens to the primary list structure.If no alternate is defined, and the primary is unavailable, eTrust CA-Top Secretdefaults to its current I/O processing.Using the Sysplex Coupling Facility 3–3