Legacy Terminals

The business need in this project was to delay the migration of the existing terminal network until the application migration from the legacy system to the new IBM system was complete.  Concurrent upgrades of the legacy application system and the legacy terminals were deemed too large to be effectively managed.  Once the new IBM system and application stabilized, the migration of portions of the legacy terminals to current technology could be easily managed.

Backstory

• New York State Police engaged in a multi-year project to migrate from a legacy Unisys mainframe to a complex of distributed IBM servers and a state-of-the-art portal.
• The timeline for installing the new system and completing the application portion was well in advance of completing the portal.
• The implementation of the portal included replacement of all statewide terminals and reprogramming all metropolitan computers.
• Full replacement of all devices and reprogramming of all metropolitan systems was expected to take up to a decade.
• A mechanism was needed to translate between the communications protocol and message formats used by the legacy terminals to the communications protocol and message formats used by the new system.
• The above included the need to replicate the security system employed by the legacy system.

Business Objective

• Allow for the graceful transition of all users and metropolitan computing systems to the new computer system

Functional Requirements

• Maintain isolation of four separate networks:
  • New York Police Department (NYPD)
  • Other Metropolitan Police Departments
  • State Police barracks (completely converted as of 1/2014)
  • Other devices (courts, prisons, parking, street maintenance)
• Check security on every transaction to determine if the submitter is authorized to submit the transaction for the accompanying data
• Support access security
• Maintain the same level of access security provided by the Unisys mainframe that was replaced
• Provide continuous operations 24/7/52

• Transition the legacy terminal input/output to IBM Websphere® MQ request/response messages
• Provide correlation identifier for message requests and responses
• Journal all traffic
• Send message delivery reports to application system

Outcome

The Plexus Message Broker successfully interfaced the legacy terminals to the new IBM system.  As part of the transition plan, the State Police terminal network was replaced eliminating the need for the State Police Plexus Message Broker.  The other three network terminals are slated for replacement.  Once completed, the need for the Plexus Message Broker as a transitional solution will be eliminated.