Introduction to Tandem X.25 Capabilities

Glossary
Glossary–10 065307 Tandem Computers Incorporated
SUT. Site update tape. Sent from Tandem to a customer, containing a particular
release of operating system software and customer-specific software that runs with the
operating system.
switched line. Line configuration for circuit-switched networks such as a public
telephone network. The physical configuration may vary for each usage as a message
is routed through switching stations.
switched virtual circuit (SVC). A temporary end-to-end connection between two DTEs
through a network. It requires call-setup packets to establish the call and call-clear
packets to clear the circuit at the end of the call.
SVC. See switched virtual circuit.
SYSGEN. System generation program that generates a system-image file. The SYSGEN
program is usually invoked by INSTALL
SysWay. Product providing access to the InfoWay service. SysWay runs as a
nonprivileged process on the customer’s Tandem system and provides a gateway to
the InfoWay service, which resides within the Tandem network.
throughput. Amount of data traffic going through the network within a given time
period. Expressed in bits per second (bps).
timeout. Time interval during which a specified action must occur.
transit delay selection or indication. Optional network facility for requesting the
maximum acceptable delay in the network in the call request packet. The network
responds in a call connected packet with the value or a lower acceptable value.
UA. Unnumbered acknowledgement. Link-level frame used to respond to a SABM,
DISC, or RSET command.
User data. Data field contained in data packets. See also call user data.
V.35. The CCITT V.35 Recommendation is a standard for a wideband 48 kbits per
second modem. V.35 is being replaced by a new V.36 standard, which uses electrical
interface characteristics that are equivalent to RS-449.
virtual circuit. See switched virtual circuit.
window size. Maximum number of packets or frames that can be transmitted without
being acknowledged.
X3PAD. Program provided with X25AM, supporting communications from a local
terminal to remote entities in the network by means of an X25AM process.
X.21. Standard related to X.25. Recommendation for the physical layer interface,
designed for digital circuit-switched networks.
X.21 bis. Standard related to X.25. Recommendation for the physical layer interface,
functionally equivalent to the electrical interfaces RS-232-C and V.24. Also adapts to
provisions of RS-449 and CCITT V.25.
X25AM. Tandem product for X.25 communications. It is a subsystem, consisting of a
process, line, and subdevice(s).