In a mixed complex, use the CTC option in GRSCNFxx to specify the device numbers of all CTC links attached to the system and available to global resource serialization. Specifying CTC links that you might have included at system generation but not yet installed causes global resource serialization to issue an error message (ISG046E) during system initialization.

When you have more than one CTC link between systems, global resource serialization uses the last device number specified as the primary link. Thus, the order in which you specify the device numbers affects how global resource serialization chooses the primary and the alternate links. If two links are on-line and available when a system joins the ring, global resource serialization chooses the second CTC link specified as the primary link and marks the first as an alternate. For example, if GRSCNFxx specifies CTC(860), followed by CTC(780), global resource serialization selects 780 as the primary and 860 as the alternate.