Notify - IBM 3708 Description

NOTIFY
The 3708 transmits a NOTIFY to advise the SSCP when a downstream device is
available for communication. By waiting to notify the SSCP until its downstream
devices are actually ready to communicate with a host application, the 3708 prevents
the access method from creating and maintaining unnecessary control blocks.
Resources are therefore requested from the access method only as required.
The fonnat of the NOTIFY command is:
THO:
X'2C'
(Secondary
-+
Primary, nonnal)
THI:
X'OO'
OAF': X'OO'
OAF':
Address of LV sending NOTIFY
SNF:
X '0000 ,
RHO:
X'OB'
(Request FMD, fonnatted, OC)
RHl:
X'80'
(DRl)
RH2:
X'OO'
RVO:
X'8l'
Network Services
RVl:
X'06'
Session Service
RV2:
X'20'
Notify
RU3:
X'OC'
Vector key
RU4:
X'06'
Length
RV5:
b'OOOO OOxl'
x
=
0 Secondary unavailable, power off.
x
=
1 Secondary available, power on.
RV6-7:
X'OOOl'
LV-LV session limit
RV8-9:
X'OOOO'
LV-LV session count
RVIO:
X'QQ'
Reserved
After each ACTLU command, the 3708 transmits a NOTIFY (power off) command
to the SSCP. This command performs two tasks. It notifies the SSCP that the
downstream device is powered off, and it tests whether the access method supports
the NOTIFY command. A negative response to the NOTIFY command indicates
that the host access method does not support NOTIFY, and the 3708 does not
transmit any more NOTIFY commands to the host.
If the host access method supports NOTIFY, the 3708 transmits a NOTIFY
command in the following conditions:
• When the downstream device powers on and a host selection is made from the
3708's host selection (C3) logon screen.
• When an EIA 232C device powers on and all 3708 logon screens are excluded.
• When the user enters a CR on a EIA 422A connected device.
• When the tenninal type is detennined either by user selection or 3708
configuration and the Host Selection (C3) logon screen is suppressed.
• When an UNBIND (OF) or a TERM-SELF (40) is generated by the 3708. The
UNBIND (OF) and TERM-SELF (40) are 3708 security features (see
"Transmission of VNBIND(OF) and/or TERM-SELF(40)" on page B-2) that
prevent dial-up users from gaining access to other user's applications. After
transmitting the UNBIND (OF) or TERM-SELF (40), the 3708 transmits a
NOTIFY to the SSCP to notify the access method of a power off condition.
Chapter 3. SDLC and SNA Communication
3-19