Use the CFLEVEL parameter to specify the level of the coupling facility in which you want the structure to be allocated. The CFLEVEL requested should identify the level of architected function that the user requires. (The coupling facility levels and the associated functionality are defined in PR/SM™ Planning Guide.) The CFLEVEL parameter is ignored if the structure is already allocated.

If a coupling facility of the requested CFLEVEL is not available, the system might allocate the structure in a lower level coupling facility. The field CONACFACILITYCFLEVEL in the connect answer area contains the CFLEVEL of the coupling facility in which the structure is allocated.

The CFLEVEL requested by each connector to a structure is saved in the CFRM active policy. Other connectors are informed of this level through their event exits — for new connection, existing connection, rebuild new connection, and rebuild existing connection events.

The CFLEVEL can be specified only through IXLCONN. To change to a different coupling facility level, you must disconnect and connect to the structure again with a different value. You also cannot change your requested CFLEVEL when rebuilding the structure. The structure might be rebuilt in a coupling facility with a different CFLEVEL, but that is dependent on the first connector to issue the IXLCONN REBUILD request and what coupling facility resources are available for allocating the new structure.

Systems at OS/390® Release 9 and higher can specify MINCFLEVEL in conjunction with CFLEVEL to ensure that if the structure is allocated, it is allocated in a coupling facility that provides the required level of functionality. See Requesting a Minimum CFLEVEL.

Note that the CFLEVEL can affect the size of a structure. Different CFLEVELs will have different control structure requirements, which in some cases may cause a structure to become unallocatable or unusable.