7.1.2 Planning considerations Keep the following considerations in mind during your planning phase. Coupling links If you are currently using CBS/CBR or CFS/CFR CHPIDs, be aware that these are not supported on a z9-109. They need to be replaced with CBP or CFP CHPIDs. These are not supported: ICB-2 links ISC-3 links in Compatibility mode Additional CHPIDs You may want to add more FC, ESCON or OSA CHPIDs into the configuration. A new eConfig is built by your IBM Representative and you receive a new CCN, so you can download an updated CFReport file from Resource Link to use as input into the CHPID Mapping Tool. HMC The z9-109 requires a new HMC and you require MCLs on the existing Support Element (SE) if you want to use the new HMC to access existing processors. The new HMC only uses Ethernet for its network connection. Hardware and software support Some software features exist that are only available with z/OS V1.7, such as Multiple Subchannel Sets (MSS). You also require HCD V1.7 to be able to define MSS which creates a Version 5 IODF.