Ethernet—with a steady migration towards Gigabit Ethernet—is now the defacto choice for today’s “electronic battlefield.” The Department of Defense’s (DoD’s) Unmanned Aircraft System (UAS) Roadmap encourages the use of “common, network-enabled electrical interfaces such as Gigabit Ethernet.” One of the reasons for this mandate is Ethernet’s maturity, which has resulted in the wide availability of Commercial-Off-The-Shelf (COTS) hard ware and software adapted for military use. Ethernet’s growth in popularity, both commercially and in military applications, is also largely driven by its native support of Internet Protocol (IP) networking. IP is an important enabling technology for the Global Information Grid (GIG), the foundation for the military’s network-centric warfare initiative.

Figure 1. EFV mission requirements dictate high-speed transport of Marine infantry from ships to inland objectives and to provide armor-protected land mobility and direct fire support during combat operations. (Photo courtesy of USMC)

However, to keep pace with the escalating demand for Ethernet, switches, routers, and wireless connectors must be continually improved. To help the military meet its current need for Ethernet-enabled vehicles and to anticipate future demands, there is increasing pressure on defense contractors to provide rugged Ethernet switches and routers that meet the requirements of SWaP2- C2 (Space, Weight, Power and Performance — Cooling and Cost). Additionally, these network switches and routers must endure the harshest environments to enhance situational awareness in unmanned aircraft, tactical ground vehicles, and maritime assets where standard commercial-grade equipment cannot survive.

Expeditionary Fighting Vehicle

One of the many significant deployments of Ethernet in the military is with the Expeditionary Fighting Vehicle (EFV) — the Marine Corps’ highest priority ground combat modernization program [see Figure 1]. Designed and developed by prime contractor General Dynamics, the EFV is an armored amphibious vehicle capable of seamlessly transporting Marines from Naval ships located beyond the visual horizon to inland objectives. The new vehicle is a self-deploying, high-water-speed, amphibious, armored, tracked vehicle, capable of providing essential command, control, communications, computers, and intelligence (C4I) functions for embarked personnel and other EFV units. These functions are to be interoperable with other Marine Corps systems, as well as with Army, Air Force, Navy, and NATO systems.

Figure 2. The latest revision of the Tactical Switch Router (TSR) integrates Gigabit Ethernet Switch cards and reliability upgrades. The previous version is shown on the left.

To support the EFV’s mission, General Dynamics initially selected Fast Ethernet as the main inter-vehicle network protocol for linking various IP-enabled computing and communications devices in the EFV. General Dynamics needed a rugged router that wasn’t yet commercially available to sustain its networking requirements. As a result, General Dynamics contracted with Parvus Corporation to develop the Tactical Switch Router (TSR), enabling the deployment of communications-on-the-move and information-sharing capabilities, supporting the Marine Corps’ net-centric operations initiatives.

The EFV includes multiple connections for a network backhaul over satellite or line of sight wireless technologies, de - pending on the vehicle variant, to fulfill its mission. Empowering situational awareness, the TSR subsystem connects to a variety of IP-enabled computing workstations and radio frequency (RF) device LRUs to support an Ethernet-based intra- and inter-vehicle network. Remote users can exchange voice, video, and data communications with a central site and securely access resources in real time.

Leveraging PC/104

Historically, military electronics have been based on VME or CompactPCI standards. However, both of these options are costly and large in size. The adoption of the Mobile IP specification allowed Cisco Systems to develop the 3200 Series Wireless and Mobile Router for mobile applications. Cisco originally invented this mobile router platform in collaboration with NASA using VME hardware. After field trials and customer surveys, Cisco redesigned it to the PC/104-Plus form-factor to provide a rugged, more compact, lower-cost version.

Figure 3. The TSR’s PC/104+ router and GigE switch card stack uses aluminum clamshell heatsinking and rigid flex circuits to ensure reliability and fanless operation.

PC/104-Plus form-factor components are well suited to the unique requirements of Mobile IP networking where shock, vibration, and other environmental extremes would otherwise destroy a system based on open desktop technology. The modular and robust design accommodates specialty add-on modules, such as Ethernet switches, GPS receivers, CPU cards or wireless modems. The notable advantages of PC/104—its compact size, PC compatibility, strong vendor support, stackable design, low-power requirements, environmental durability and simple maintenance— make it an ideal foundation for Mobile IP networking in military applications.

COTS Developments

By basing the TSR router on Parvus’ COTS DuraMAR Mobile IP router product, the EFV could benefit from a rugged router system that integrates Cisco System’s Rugged 3200 Series Integrated Services Router (ISR). The pervasiveness of Cisco technology and its IOS software in the government arena is a critical factor for specifying this routing technology in the TSR. According to industry reports, Cisco has at least a 70 percent market share in the US Government’s IP network infrastructure. By including network management software that the US Marines have been trained to operate, the learning curve would be diminished and the EFV’s time to deployment would be improved.

The use of 3200 Series router technology in the TSR was also imperative to meet the requirements set forth by General Dynamics for ruggedness and high performance. Parvus designed the subsystem with a flexible, compact form factor ruggedized to withstand the extreme thermal and vibration environments encountered by the EFV’s tracked vehicle operation. The rugged 3230 ISR is specifically designed for establishing a highly secure mobile IP network with remote devices in a moving or stationary vehicle. Remote users can exchange voice, video, and data communications with a central site and securely access resources in real time.

“Future-Proofing” the EFV

As the DoD moves toward upgrading to Internet Protocol version 6 (IPv6) this year, support of IPv6 has become a core requirement for network-centric warfare. Therefore, compatibility with IPv6 was another must-have feature for the TSR to “future-proof” the EFV. IPv6 makes it possible to implement new net-centric warfare concepts and guidelines, and also allows for advanced networking capabilities when compared with IPv4. IPv6 also offers improved functionality for Internet capable devices, applications and services. Therefore, it was essential that the TSR was IPv6 compatible to help ensure a net-centric device.

In keeping pace with the initiative to “future-proof” the EFV, Parvus’ latest revision [see Figure 2] of the TSR integrates two PC104+ Gigabit Ethernet switch cards into a new chassis to provide a total of 17 Ethernet ports—more than triple the number of available ports on the original TSR configuration. By integrating 3200 series mobile access router technology together with PC/104+ Gigabit Ethernet switch cards, the TSR offers expanded LAN port count and consolidated switch and router functions into a single hardened subsystem designed to MIL-STD-810F and MILSTD-461E environmental conditions. Sealed MIL-C-38999 connectors bring out an IOS-managed 10/100 WAN port, three IOS-managed 10/100 switch ports, and 13 10/100/1000 Gigabit Ethernet switch ports, as well as two multi-protocol serial ports and an RS-232 management console port. These additions supply the EFV with enough capacity to meet future networking demands.

Since receiving the original TSR development contract in 2007, Parvus has received additional contracts for reliability improvements and functional upgrades to ensure system performance. Among these improvements were upgrades in ruggedness and thermal design. Flex cabling was instituted to improve shock vibration and provide solid reliability. Conduction cooling advancements were also instituted, such as clam shell heat sinks for each printed circuit card assembly and finned extruded chassis to reduce thermal issues and improve reliability [see Figure 3]. As Gigabit Ethernet products consume more power than Fast Ethernet ones, thermal management and mechanical enhancements became critical.

Rugged Ethernet Marches On

As critical functions such as sensor interfaces, display processing, digital map servers and data recorders became increasingly important in net-centric operations, Gigabit Ethernet provides the needed bandwidth to accommodate these data-intensive and time-critical applications.

To keep pace with the demand for Gigabit Ethernet, switches and routers have evolved to provide more functionality and management capabilities. The network router is quickly changing from a device dedicated to connecting disparate networks to an integrated services device capable of multiple functions beyond routing. Sophisticated routers can provide voice, video, data and Internet access, wireless, and other applications. Likewise, now that switches have onboard processing and Ethernet-enabled management features, switches can support such capabilities as VLANs, Link Aggregation, Spanning Tree, IPv4, IPv6, Traffic Policing, Quality of Service (QoS), Guaranteed Bandwidth and SNMP. The ongoing development of Ethernet switches and routers is blurring the distinction between the two technologies.

Although Gigabit Ethernet applications are forging ahead at break-neck speed, switching and routing technology need to keep pace with these developments to ensure successful implementation.

This article was written by Mike Southworth, Director of Marketing, Parvus Corporation (Salt Lake City, UT). For more information, contact Mr. Southworth at This email address is being protected from spambots. You need JavaScript enabled to view it., or visit http://info.hotims.com/22926-401.

Embedded Technology Magazine

This article first appeared in the September, 2009 issue of Embedded Technology Magazine.

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