Remote system session establishment is slightly different
for a type 2.0 (T2.0) node than for a type 2.1 (T2.1) node. Session
establishment for each node type is explained below, and examples
of session establishment activities between the HP e3000 and the
IBM remote system are shown later in this chapter.
For a Type 2.0 Node |
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The System Services Control Point (SSCP) uses PU-SSCP sessions
to control the PU in each node in its domain. Each PU, in turn,
controls the resources of the node it resides in. These resources
include the links which have been configured for the particular
node. The SSCP transmits an ACTivate Physical Unit (ACTPU) command
request to the PU to establish a session with the PU. When a PU-SSCP
session is activated, the node that contains that PU becomes an
active node in the SNA network. SNA Transport manages the PU-SSCP
sessions of the HP e3000.
The SSCP uses LU-SSCP sessions to control dependent LUs and
to establish dependent LU-LU sessions. The SSCP sends the command ACTivate
Logical Unit (ACTLU) to establish LU-SSCP sessions. SNA Transport
manages LU-SSCP sessions on the HP e3000.
A dependent LU-LU session enables data to be exchanged between
two end users, between an end user and an application running on
the host processor (such as TSO), or between a job and the Job Entry
Subsystem (for example, JES2) running on the host. The LU-LU session
can be thought of as a temporary logical connection that allows
two LUs to exchange data.
LUs on the HP e3000 communicate with the SSCP to establish dependent
LU-LU sessions. A dependent LU sends a session initiation request
to the SSCP via its LU-SSCP session. The SNA services manage the
LU-LU sessions on the HP e3000.
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