APPC Subsystem on MPE/XL Node Manager's Guide (30294-90007)

244
implement the same functions as
control operator commands. (See
control operator commands.)
conversation: The logical
communication between two
transaction programs.
Customer Information
Control System (CICS): An
IBM application subsystem that
provides file handling and data
communications services for
application programs.
D
dependent LU: An LU capable
of conducting only one APPC
session at a time. A dependent
LU always functions as a
secondary LU; that is, it cannot
send a BIND to initiate a session
but must wait for the host to send
the BIND. It can send an
INIT_SELF to the host to solicit a
BIND, or it can be configured to
accept unsolicited BINDS. See
independent LU.
domain: The part of a network
managed by a Systems Services
Control Point. This includes the
Physical Units (PUs), Logical
Units (LUs), and links that the
SSCP activates, deactivates, and
otherwise manages.
E
end user: The ultimate
destination of data in a
communications network. An end
user can be a human user, a
peripheral device (like a printer
or a terminal), or an application
program.
F
first speaker session: A locally
controlled session. See locally
controlled session.
FM header: See Function
Management header.
FunctionManagement header
(FM header): A header that
selects the destination or source
for subsequent data transmission
and supplies information for
other data management tasks.
G
Generalized Data Stream
(GDS): The name of the LU 6.2
data stream. LU 6.2 data packets
must include GDS headers (see
GDS header).
GDS header: A portion of an LU
6.2 data packet that contains
information about the kind of
data being sent or received.
H
half-session: An SNA session
must be supported by two sides. A
half session is the resource on a
Network Addressable Unit that
provides FMD services, data flow
control, and transmission control
for its half of a complete session.