Ending Host Sessions And Disconnecting From The 3708; Sna Hosts; Unconditional Disconnection And Session Termination; Conditional Disconnection - IBM 3708 Description

Ending Host Sessions and Disconnecting from the 3708
SNA Hosts
When operating with the 3708, an end-user device can have two sessions to be
concerned with: the session with the host application (either an SNA host or an
ASCII host), and the session with the 3708. To distinguish between the two sessions,
the device is said to be "in session" with the host and "connected to" the 3708.
This section describes the conditions under which the 3708 disconnects a device from
an SNA host.
Unconditional Disconnection and Session Termination
If a device is in session with the host and the 3708 detects any of the following, the
host session is ended and the device is be disconnected from the 3708:
• Loss of host connection (for example, DSR drop)
• Reset of SDLC link, SNRM command received
• Disconnect of SDLC link, DISC command received
• SDLC Inactivity Time Out value exceeded
• Unexpected DACTLU
• Deactivation of PU, DACTPU command received.
If the device is a display, the 3708 sends the message HOST UNAVAILABLE. RETRY
LATER before disconnecting the device.
Conditional Disconnection
If the SNA host sends an UNBIND or DACTLU for a specific LU while an
SLU-PLU session is active, the host session ends. In addition, the 3708 interrogates
the DISCONNECT option value for the affected port to determine whether to
disconnect the port. The possibilities are as follows:
o -
Unconditionally disconnect at UNBIND or DACTLU
1- Never disconnect at UNBIND, but disconnect at DACTLU
2 - Disconnect at UNBIND, if UNBIND type is other than 2 or 3, and disconnect
atDACTLU
3 -
Disconnect at UNBIND, if UNBIND type is other than
1, 2
or 3, and
disconnect at DACTLU
4 - Disconnect at UNBIND, if UNBIND type is other than 2 or 3, but do not
disconnect at DACTLU
5 - Disconnect at UNBIND, if UNBIND type is other than 1, 2 or 3, but do not
disconnect at DACTLU.
Note: Options 4 and 5 are provided primarily for TSO users. TSO normally sends
a DACTLU rather than an UNBIND to end the session.
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IBM 3708
Description