APN Configuration and Management Manual

Glossary

SNAX/XF and SNAX/APN Configuration and Management Manual—425836-005

Glossary-3

basic information unit (BIU)

basic information unit (BIU). The unit of data and control information that consists of a

request/response header (RH) followed by a request/response unit (RU).

basic transmission unit (BTU). Information that the data link control sends over a link. A

basic information unit can consist of one path information unit (PIU), several PIUs, or a

part of a PIU.

BIND command. The Systems Network Architecture (SNA) command that includes

information necessary to establish a session between two logical units (LUs).

Bind entry. A BIND image record in a BIND table.

Bind table. A table that contains BIND images named in BIND entries.

BIU. Basic information unit.

block mode. A mode of operation in which computer programs and devices exchange data

in quantities greater than the line size of the particular device.

BTU. See basic transmission unit (BTU).

call-in. Receipt of a request for the establishment of a switched connection using

SNAX/CM.

call-out. A request for establishment of a switched connection using SNAX/CM.

CCITT. Comite Consultatif International Telegraphique et Telephonique (International

Telegraph and Telephone Consultative Committee). An international organization that

makes recommendations for data communications standards.

CDI. Change direction indicator.

channel status word (CSW). An area in storage that provides information about the

termination of I/O operations.

character-coded logon. A character string sent by a remote LU to request logon to an

application. In SNAX/XF and SNAX/APN, character-coded logons are interpreted by

the LUNS interface with reference to ESS tables.

character set. A defined collection of character representations valid for a particular

program, printer, or language.

class of service (COS). SCOS is a means of expressing the desired quality of a route

through an APPN network. In the NonStop end node implementation, COS is

configured by use of the TG attributes such as TGBYTECOST.

CLIP. See communications line interface processor (CLIP)