Physical Unit (PU)

Although the name physical unit (PU) strongly implies a hardware component, a PU is an IBM naming convention for hardware and software combinations that perform a specific task in an SNA network. For example, PU 5 represents not only the mainframe itself, but also the mainframe software components (such as SSCP and VTAM) within the SNA network.

The following table lists the SNA defined PU types and a brief description of each.

PU numberDescription
PU 1Terminal Controller (IBM 6670, 3767)
PU 2Cluster controller running configuration support programs (IBM 3174, 3274, 4701, 4702)
PU 2.1Peer-to-Peer (APPN), used primarily in AS/400 networks
PU 4IBM Front End Processor, usually running ACF and the Network Control Program (IBM 3754, 3725, 3720, 3745, 3746)
PU 5IBM Host (mainframe) system

See Also

SNA Service

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