Use Case: Executive, Executive Package: Exec_OperLogin

It is possible for Operators to log into the system from any number of locations (e.g. outside the computer firewall) and monitor the system performance. The login sequence including possible acquisition of control privileges is shown by this Use Case.

Goal:   Login Operators.

Contact Author:   P. Grosbol

Role(s)/Actor(s):
Primary:  

Secondary:  

Priority:   Major

Performance:   On the order of seconds

Frequency of Use:   A few times per day

Preconditions:

  1. The ALMA software system is running.
  2. The ALMA software is installed on system from which the remove operator access is requested.

Basic Course:

  1. The Operator stars the client application
  2. The availability of CORBA services it checked and started if needed
  3. The connection to the main ALMA system is established by issuing a login request, which includes user-id and password, to the ExecServer
  4. The ExecServer authenticates the user login request by comparing the information with the ALMA user database.
  5. A access token is returned on successful.
  6. The client requests the status information by registration for the specific information it wants at the ExecServer using its login token
  7. Whenever new information is available to the ExecServer it will send an event to all client which have asked for it.
  8. The client will request the new information when it receives the event.
  9. The Operator may also request control privileges for a specific set of tasks (e.g. a sub-array control).
  10. The Operator sends a control request to the ExecServer.
  11. The ExecServer asked the main operator to confirm and accept the request.
  12. If granted, a new token is issued which give control privileges
  13. The remote operator issues the commands using the new token.
  14. Alternative Course:

Postconditions:

  1. The operator have access to a client GUI on the current system

Issues to be Determined or Resolved:  

  1. none at this time

Last modified: 31oct03