AVIONICS & MOBILE CASE STUDY: WIRELESS LAN MANAGER
Development Model: Waterfall
Languages: CT, LML, COBRA
Technologies and Tools: Oracle, SNMP
Genova Technologies developed this world-class application as part of an onboard information network, providing an international transportation customer with a unique system that provides in-flight wireless access to information on an aircraft server, as well as information available on the Internet. Using this technology, airline customers can surf the Internet or check their email while in flight.
Crew members can also use the system to support applications that eliminate many of the paper forms required upon arrival and before departure. Using the system’s wireless LAN, these applications exchange data between the aircraft and the airline’s network at the airport, enabling the airline to save both time and money.
The Wireless LAN Manager (WLM) provides management and health monitoring of the wireless LAN hardware within the unique environment of the aircraft. WLM ensures that the wireless LAN is disabled during critical phases of flight. When the wireless LAN is enabled, WLM ensures that it is operating at a frequency legal in the country where the aircraft is currently located.
WLM is a complex software development effort that requires frequent communication with others involved in the development of the total system, to define the many external interfaces WLM is required to support. WLM supports the following external interfaces:
• SNMP communication with the wireless hardware
• Proprietary communication with the wireless hardware
• Interfaces to two CORBA service processes
• Interface to a discrete I/O driver
• Interface for secure communications to an avionics data controller unit
• SNMP communication with SNMP manager applications
• Interface to an Oracle database
• Interface to XML files for configuration data
• Interface to support/manage upgrades of wireless hardware’s Internetwork Operating System (IOS)
Challenges, Successes, and Lessons Learned
Because of the many external interfaces, the application design was required to be multi-threaded to prevent delays in communication over the interfaces. Genova implemented several design patterns within the application to meet performance requirements and provide flexibility as external interfaces changes over the life of the program.
Initial development began with the use of a third-party library to handle direct communication with the wireless hardware. After some early testing, it was determined that the third party library could not support all the requirements. Genova developed a replacement library that required a detailed understanding of how to configure and communicate with the wireless hardware. The new library met all requirements, delivered a 10-fold increase in performance and is estimated to save the customer approximately $2 million over the life of the program.
WLM was initially targeted to run only on the Windows operating system. Recent efforts have required a port to run on Linux. Due to up-front design considerations at the beginning of the project, porting the existing application to Linux was accomplished in approximately 6 weeks.
Multiple variations of the WLM project are currently deployed on three separate airframes.
The most recent iteration introduced a new unit for WLM to manage in the Universal Mobile Telecommunication System (UMTS). The UMTS provides the capability to establish either a cellular or Wi-Fi connection to a ground access point depending on availability at the geographic location.
WLM is currently in production and has been installed on commercial aircraft.
Team Composition and Responsibilities
During the development of the WLM application, Genova engineers provided the following efforts:
• Software requirements definition and documentation
• Complete software design of the application and some of the external interfaces with required design documentation
• Software development and coding
• Unit testing of all code
• Software acceptance test plan and procedures documentation
• Support for system integration with actual hardware both locally and in Toulouse, France.
• Installation and configuration support documentation
Applicable Technologies Used