2096DEVICE, and 2094DEVICE Preventative Service Planning (PSP) buckets prior to implementation. 9.2 Connectivity HiperSockets has no external components or external network. There is no internal or external cabling. The HiperSockets data path does not go outside the System z server platform. HiperSockets is not allocated a CHPID until it is defined, and it does not take an I/O cage or an I/O drawer slot. If you have used all of the available CHPIDs on the System z server, you cannot enable HiperSockets. Therefore, HiperSockets must be included in your overall channel I/O planning. HiperSockets TCP/IP devices are configured similar to OSA-Express QDIO devices. Each HiperSockets requires the definition of a CHPID like any other I/O interface. The CHPID type for HiperSockets is IQD, and the CHPID number must be in the range of hex 00 to hex FF. No other I/O interface can use a CHPID number defined for a HiperSockets, even though HiperSockets does not occupy any physical I/O connection position. Real LANs have a maximum frame size limit defined by their architecture. The maximum frame size for Ethernet is 1492 bytes, and for Gigabit Ethernet there is the jumbo frame option for a maximum frame size of 9 kilobytes (KB). The maximum frame size for a HiperSockets is assigned when the HiperSockets CHPID is defined. Frame sizes of 16 KB, 24 KB, 40 KB, and 64 KB can be selected. The default maximum frame size is 16 KB. The selection depends on the characteristics of the data transported over a HiperSockets, and is also a trade-off between performance and storage allocation. The MTU size used by the TCP/IP stack for