SNA IMF/XL Node Manager's Guide (30293-90010)

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Request Unit (RU): A message
unit containing control
information such as a request
code, or function management
headers, end-user data, or both.
Response Header (RH):
Control information that
indicates whether a response is
positive or negative. A response
unit optionally follows it.
Response Unit (RU): A
message unit that acknowledges
a request unit. If the response
unit is negative, it will contain
sense data that defines the
exception condition. If the
response unit is positive, it may
contain additional information;
for example, it may contain
session parameters in response to
BIND SESSION.
RH: See Request Header or
Response Header.
RU: See Request Unit or
Response Unit.
S
SDLC: See Synchronous Data
Link Control.
session: A logical connection
between two networkaddressable
units that allows them to
communicate.
SNA: See Systems Network
Architecture.
SSCP: See System Services
Control Point.
Synchronous Data Link
Control (SDLC): An IBM term
for a link protocol used for the
transfer of data between stations.
The information transfer is
synchronous, thus eliminating
the need for start and stop bits. It
is also code-transparent,
transmitted serial-by-bit, and
may be transmitted in duplex or
half-duplex over switched or
nonswitched links. The link
configuration may be
point-to-point, multipoint, or loop.
SystemServices Control Point
(SSCP): A part of an SNA host
node that helps to manage
configurations, controls network
operations, does problem solving,
and provides other session
services for end users. An SSCP
exists only in the host and is
exercised by the host’s
communications access method.
Systems Network
Architecture (SNA): A
comprehensive specification for
distributed data processing
developed by IBM. SNA defines a
layered protocol for
communicating and controlling a
communications network within
the IBM environment.
T
TERM-SELF: AnSNArequestto
the SSCP to terminate an LU-LU
session.
TH: See Transmission Header.