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Chapter 7. Configuration with HCD > ETR and STP Sysplex Timer - Pg. 218

7.15 ETR and STP Sysplex Timer The external timer reference (ETR) and the Sysplex Timer Protocol (STP) are not defined in HCD. However, the STP uses coupling facility (CF) links for communication between processors. The links can be either dedicated to STP or used for both STP and CF links. You cannot define CF links for STP only between two processors if you have CF links for coupling facilities that connect the same processors; this is verified on the processor level (not only on the LCSS level). If you attempt to define links, a message is displayed. See Figure 7-171. +-----------------------------------------------------------------------+ | Mixture of STP and CF links not allowed between processor CPCPKR1 and | | processor CPCPKR2. | +-----------------------------------------------------------------------+ Figure 7-171 HCD: Mixture of STP and CF links not allowed If used for STP only, the control units of type STP are added automatically by HCD. No devices will be defined. The CU type for CF links is displayed on the CF Channel Path Connectivity List panel. For more information about STP planning and implementation see Server Time Protocol Planning Guide, SG24-7280 and Server Time Protocol Implementation Guide, SG24-7281.