Sun Microsystems SunLink SNA 9.1 PU2.1, Руководство по настройке

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SNA Concepts C-9
C
C.2.3 Sessions
Like data in hierarchical SNA networks, data in peer-to-peer SNA networks is
transferred between logical components using SNA sessions. A session
provides a logical communications pipe between end users and host
applications. The following table describes the two types of peer-to-peer SNA
sessions.
In addition to acting as either primary or secondary LUs, independent LUs
also support parallel sessions between LUs. An independent LU
communicating with another independent LU over multiple, parallel sessions
can be the primary LU on some sessions and the secondary LU on others.
The following is an example of a peer-to-peer SNA session:
•
An LUType 6.2 transaction program (TP) requests a conversation with a
remote LU.
•
The PU2.1 CP receives the request, assigns an address, and activates links, if
necessary.
•
The LU, in conjunction with the PU2.1 CP, establishes a session.
•
The LU attaches to a remote TP with information supplied by the local
program.
•
LU-LU data is exchanged over the conversation.
CP-CP sessions are used in APPN-based nodes to exchange control
information about directory and topology services. Such functions are used for
remote LU location and route selection. For more information about APPN,
refer to Section C.4, “LEN and APPN,” on page C-10.
Table C-3 PU2.1 Nodes Session Types
Type Connected Nodes Function
LU-LU Applications and
applications Data transfer.
CP-CP PU2.1 control points Facilitate APPN-based SNA
communication.