Total Control MP/16, Operator'S Manual

Page: 39 / 182

Using Total Control MIBs 3-3
If the Result changes to success, the requested command is
complete.
If the Result changes to aborted(6) or failed(7), the Code object
reveals a further description of the reason for which the requested
command could not be done.
Additional Command Table Features
The
Param
object can be used to pass parameters to the command
table. Most commands do not require additional parameters. If
used, this parameter must accompany the
Function
object in a
single SET PDU.
The
Force
object can be used to force the command to be issued in
cases where the proxy agent would otherwise warn the Network
Manager and say it was unAbleToRun(5). One such example of
this is if the requested function is to reset a modem that is currently
in a connected state. If used, this parameter must accompany the
Function object in a single SET PDU or be set prior to SETting the
Function
object.
Lastly, the command table makes provisions for the environment
where multiple management stations are possible. Two objects,
MgtStationId and ReqId , are used for this purpose. MgtStationId is a
writeable object that is provided for optional use by the
management station. If desired, it can set this object to a unique
value in the same PDU as is used to set
Function , Param and Force .
The value of the request-id field of the SNMP SET (used to set the
Function) is internally stored and returned upon GETting the read-
only
ReqId
. While GETting the command
Result
and
Code
, it makes
sense to GET MgtStationId and ReqId in the same PDU to guarantee
that the results the management station receives are related to the
command that it had requested (and not some other management
station).
The proxy agent will generally not allow a second command of the
same type as one already in progress for a given device. However,
after completion of one command, it is possible that a second
command could be issued and received before a management
station had been able to GET the results of the first command. This
is the reason for the additional complexity using
MgtStationId
and
ReqId .