SPECIAL FEATURE
partnership with Parvus Corporation, Cisco technologies are strengthened and hardened for use in all military platforms including ground tactical, aerial, missile defense, amphibious and satellite programs. To make the previously mentioned mobile networking capabilities viable for military use, they must be enclosed in subsystems that are SWaP-optimized as well as mechanically stable under extreme environmental conditions, and fully certified to MIL-STD-810G (thermal, shock, vibration, humidity, exposure to dust, water). Recently, Parvus announced the DuraMAR 5915 (Figure 2), a Cisco IOSmanaged mobile router that includes the latest Cisco IOS networking capabilities such as RAR and IP Multicasting. The following ruggedization and mechanical design procedures were implemented to ensure the latest developments in networking technology can be deployed in military applications.
In this example, imagine a radio path where enough bandwidth exists to transport video and voice traffic. Being a line of sight radio in a vehicle in motion, the path can become blocked or degraded (Figure A). With RAR, the traffic can be diverted to the back-up satellite path within milliseconds, and moreover, a QoS policy can be applied to allow the higher priority voice traffic to get through (in this example, the SATCOM link does not have enough bandwidth to reliably transfer the voice AND video). Without RAR, the router would have no way of knowing the line of sight radio path was lost EXCEPT by using routing protocol timeouts taking seconds…or even tens of seconds. With RAR, the radio notifies the router as soon as the link loss event occurs at the radio network layer. RAR provides a standard interface between radios and routers as well as improved performance in reacting to changes in the radio network.
Drop Video Continue Voice
64 Kbit/s Voice
SATCOM Link 512 Kbit/s
1 Mbit/s Video
Modular Network Subsystems A sought-after feature in many of today’s military networking subsystems is modularity. Modular designs provide superior longevity and flexibility as subassemblies can be upgraded in the future without a complete system redesign—an especially attractive feature to organizations faced with tightening budgets. For example, the DuraMAR 5915 incorporates a modular rugged enclosure with building block chassis segments that have pre-integrated PC/104 card sets, along with MIL connector interfaces and optimized thermal management devices. Depending on customer requirements, a particular functional card set can be configured for standalone use—for instance as a computer, router, or Ethernet switch—or attached to each other and consolidated within a single, compact mechanical solution. Compared to the traditional approach of working around a fixed-sized box with a pre-defined number of open card slots, this modular approach provides greater f lexibility, superior technology reuse and provisions for mechanical adaptations.
Ethernet 100 Mbit/s
Radio Link 2 Mbit/s
64 Kbit/s Voice
Figure A
Radio Aware Routing (RAR) offers a standard interface between radios and routers along with improved performance in reacting to changes in the radio network.
Thermal Management Techniques With heat issues often credited as the largest contributor to system failures, ruggedizing the DuraMAR 5915 to meet these thermal challenges was a critical step. Thermal management for defense applications has always been a challenge because of the high operating temperatures of the latest processors and dense packaging needed for environmental ruggedness. By incorporating conductioncooling techniques to maximize the heat transfer, the new DuraMAR unit can remain fanless and passively cooled with no moving parts, increasing the reliability of networking capabilities. Further identifying any potential thermal management issues, engineers
used thermal modeling software to analyze potential cooling issues, ensuring the ruggedized networking subsystem will meet specific military standards. Infrared imaging cameras were also used to locate any hot spots or thermal concerns. By running a variety of analyses, engineers can quickly determine where potential points of failure could exist when subjected to the extreme temperatures encountered by the military, and design the system to lessen the risk of component failure.
Ruggedizing for EMI Protection For any device to be military-ready, it must first prove itself through compliance testing to a number of Military November 2012 | COTS Journal
21