ViewPoint Manual

Customizing ViewPoint
ViewPoint Manual—426801-001
6-30
Commands for and Responses From the
Status Server
certain function to be performed, the ViewPoint software sends a message to the status
server requesting that function. The status server performs the specified function, then
returns a response message to the requester.
The ViewPoint requesters send six types of commands to the status server. The
commands are:
•
SCAN-ITEM and NEXT-ITEM
Ask the server for information about status items that the server supports. (Each
status server must maintain a list of all the status items it supports, with default
option values for each.)
•
CHECK-ITEM
Asks the server to check the configuration of a status item that is about to be added.
•
SAMPLE-ITEM
Asks the server to retrieve current data for a status item.
•
SAMPLE-LIST
Asks the server to return information on several status items with one request.
Retrieving data on status items is the task most frequently performed by the status
server.
•
GET-VERSION
Asks the server to identify the message interface version that the server implements.
The SCAN-ITEM, NEXT-ITEM and CHECK-ITEM commands are created for the
Status Item Configuration screen when the operator presses the corresponding function
keys. The SAMPLE-ITEM and SAMPLE-LIST commands are created for the Network
Status Summary screen after the items have been configured. (Refer to Section 3,
Definition of ViewPoint Screens for information about these screens.) The
GET-VERSION command is issued prior to any SAMPLE-LIST command to ensure
that the version is one that supports SAMPLE-LIST.
Each command message consists of a header structure, a command code, and command
data. Each response message consists of a header structure and response data.
Figure 6-8 shows the DDL for the command and response message headers, which are
common to all messages.