CIWS Reengineering

The existing real-time Corridor Integrated Weather System (CIWS) demonstration system has been a cornerstone in a multi-year concept exploration project to determine the operational utility of improved current 3D weather information and 0–2 hour forecasts for air traffic management (ATM) in the highly congested Great Lakes and Northeast Corridors regions. The flexibility built into the design of the original prototype has been critical in allowing for the rapid evolution of CIWS in response to feedback from the operational users of the products and from developers of integrated weather–ATM decision support tools.  Their recommendations from the field have motivated the continual expansion in the system – both in capability and in geographical coverage.  

However, the real-time demonstration system faces several end-of-life issues, which must be addressed if we are to continue to support the FAA’s long-term vision for CIWS as a platform capable of providing the FAA and our research partners with timely, reliable aviation weather products well into the future. These issues have provided the focus for the CIWS reengineering project, which is expected to lead to a system that is both suitable for operation by FAA at its William J. Hughes Technical Center and is structured to allow ready insertion of new technology at regular intervals.

Addressing Obsolescence in Hardware and Software

The first issue is the obsolescence of the existing infrastructure and the related operational overhead associated with the aging prototype.  The 2007 system consisted of a heterogeneous network of compute nodes, many of which can no longer be maintained or repaired. In addition, a number of the software libraries used by the algorithms are no longer well supported – some of their components having been made obsolete or redundant by the advances in the ANSI C++ standard library implementations. In some cases, the oldest software components cannot be rebuilt on the new systems available from the vendors. The logistical issues posed by the aging infrastructure are felt in both the management and operation of the prototype, leading to significant extra administration and monitoring in order to meet the high availability requirement associated with the demonstration.

Linux clusterLinux Cluster used for reengineered CIWS.

The reengineered CIWS system will be largely homogeneous in both hardware and software.  A 150 node Linux cluster forms the heart of the new product generation system.  Each node is a Dell PowerEdge 1955 Blade configured with two dual-core 2.9 GHz processors, 8 GB of memory and dual gigabit Ethernet.  The cluster is highly scalable in both compute and input/output bandwidth, which allows for a potential increase in both the complexity of the algorithms supported and the richness of the product suite that can be offered.

The use of the cluster not only addresses the immediate system obsolescence issues, but also mitigates some of the system administration and real-time monitoring load associated with the 24 x 7 operation of the CIWS demonstration system. The hardware is inherently reliable due to the form factors used, the dual hot swappable power supplies, and uninterruptable power supplies. In addition, open-source cluster management tools (e.g., ROCKS and Ganglia) provide much-improved capabilities for system management and simplify the system control and monitoring tasks. Special fault handling software, based on the concept of cluster virtualization, is under development to further reduce the system monitoring burden. This software allows a set of processes running on a single virtual node to be automatically rescheduled to another physical node should a non-recoverable fault occur.

Scalability, Expansion, and Standards-based Design

The second consideration for the reengineered system deals with scalability concerns for both product-generation and display software. With the deployment of the cluster, the performance limitations of the hardware system have been mitigated. However, scalability issues inherent in the current software design remained. In order for the CIWS grid to grow beyond its current size, which is about 1/3 the size of the grid planned for 2008, significant changes to the computing paradigm were required. The reengineered system has been designed to decompose the grid into subgrids, parallel­ize the computation, and efficiently recombine the components into final results. For this new paradigm to be effective, a common representation of the grid over the entire domain is required. Moreover, automated mechanisms for decomposing the grids and processes are needed in order to readily balance the loads, change the partitioning of the system, and be able to achieve desired end-to-end performance in response to enhancements in the product generation algorithms. As part of the software redesign, the reengineering effort has provided an opportunity to take advantage of common coding standards, to leverage shared utilities and libraries and to document the software using standard tools such as Doxygen – all of which will contribute to what is anticipated to be a smooth transition of the software to the FAA.

One of the important features of the new CIWS system is the connection between the design of the new prototype and the long-term plans within the FAA for managing the dissemination of sensor data and products.  The FAA’s future net-centric infrastructure, System Wide Information Management (SWIM), is shown on both sides of the CIWS product generator in Figure 1.  Because the reengineered CIWS system is considered a “native SWIM application”, it is expected that it will leverage emerging standards for the creation of the necessary dissemination services so that it can keep pace with the evolution of NextGen. Once SWIM is in place, the SWIM infrastructure will deliver observations and sensor and model data to CIWS through a single network point of presence and will manage the dissemination of the products from CIWS to the other nodes in the NextGen.

The continental U.S.-wide products from the reengineered CIWS prototype are scheduled to be available to users in the summer of 2008.

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