HP Mainframe Connectivity Design Guide

Sysplex System complex. Multiple system images running on multiple CPCs that share I/O devices, are

connected through the cross-system coupling facility (XCF), and are contained in a single mainframe

chassis.

See also Parallel Sysplex.

Sysplex timer A central clock service that provides common time references to all CPCs in a Sysplex, Parallel

Sysplex, or GDPS configuration.

system generation The tools and process used to configure the mainframe.

TCP Transmission Control Protocol. An IP address protocol.

TDM Time division multiplexing.

TI Traffic isolation. A type of zoning.

topology The physical structure of interconnected components that form a network.

UCB Unit control block. Also known as the device address, identifies a peripheral device to the system.

UCW Unit control word. A system-generated cross-reference table that contains an entry for each

configured device address. Used to correlate the subchannel number to the UCB for each

peripheral device.

unit address/unit

number

See device address.

UNITADD Unit address. The starting address of a range of devices configured in the LCU.

volume See device.

VOQ Virtual output queuing. A C-series feature used for nonblocking architecture.

VPN Virtual private network.

VSAN Virtual storage area network. A logical SAN partition that can be configured and managed

independently.

VSM Virtual Storage Manager. A Sun Microsystems product that combines hardware and software to

present virtual tape drives and virtual tape volumes to mainframe applications.

VTC Virtual tape controller.

VTS Virtual Tape Server. An IBM product that combines hardware and software to present virtual tape

drives and virtual tape volumes to mainframe applications.

WDM Wavelength division multiplexing. The technique of placing multiple optical signals on a single

optical cable simultaneously.