Military Embedded Systems

Embedded computing systems take IPv6 switches to heart


December 01, 2006

Duncan Young

GE Intelligent Platforms, Inc.

Military operations have seen a massive emphasis shift from the physical domain of the soldier, tank, or combat aircraft to the informational and intelligence domains. This drive toward tactical awareness domination will be the key to the efficiency and speed of military operations in the future networked digital battlefield

Military operations have seen a massive emphasis shift from the physical domain of the soldier, tank, or combat aircraft to the informational and intelligence domains. This drive toward tactical awareness domination will be the key to the efficiency and speed of military operations in the future networked digital battlefield. Obviously, much enhanced communications capacity and security will be needed at all levels to implement these network-centric operations. This is why IPv6 has been selected as the common future protocol for sharing voice, data, and video across all levels of operations from the soldier and sensors, to weapons platforms, to logistics, to planning and strategic operations.

IPv6 is the foundation of interoperability for the DoD’s Global Information Grid (GIG), which uses Internet technology to provide seamless integration of information all the way from an Unmanned Aerial Vehicle (UAV), a helicopter, or a soldier in the field, to the Pentagon and back (known as reachback). IPv6 has been selected now to allow time for the creation of new infrastructure plus the gradual transition of legacy systems from IPv4 to IPv6. After many years of worldwide adoption, IPv4 is finally running out of steam, requiring three major areas of improvement for military applications that are resolved by IPv6:

Much larger addressing range without resorting to address translation – IP was conceived long before the Worldwide Web became the force it is today, resulting in just not enough address space to go around. Current IP addresses have a 32-bit field giving approximately 4.3 billion unique addresses but, because of different classes of address, typically only 3 billion of these are readily available. The number of Internet users is doubling every year and will very soon exceed the number of addresses available. However, Network Address Translation (NAT) is used extensively by local networks and ISPs whereby just one global IP address can be mapped to many local unregistered IP addresses, thus extending the number of potential users to many times that which would be available directly. IPv6’s 128-bit address field reduces the need for address translation and would allow a very large user such as the DoD to assign its own unique IP addresses to every intelligent node and subsystem in its entire inventory without NAT.

Built-in protocol and payload encryption While IPv4 supports some levels of encryption, it is implemented as an add-on rather than an inherent part of its functional capability. The additional encryption support provides military applications with the security needed for the protection of data and command structures, although it requires more processor power within a switch for effective network operation.

Selectable Quality Of Service (QOS) for different classes of communications – High priority and security are vital for critical applications where real-time response and data integrity must be achieved. Other services may be less time-critical and may not need to rely 100 percent on data integrity. Streaming MPEG video is a good example of such a service where decompression and reconstruction can tolerate some timing jitter and data errors created by transmission through a network.

At the heart of almost every operational platform – such as warships, submarines, armored vehicles, heli-copters, combat aircraft and so on – is a combat system or a mission system. In addition, there will be a mix of current and legacy subsystems, weapons, and sensors attached, using both point-to-point connected (for example, federated) and networked architectures for interconnection. With the exception of a few newly designed platforms, these older platforms are the ones that will present the greatest challenges to the introduction of IPv6 and integration within the GIG. For example, a Naval combat aircraft, such as an F/A-18 Super Hornet, might have sophisticated networked connectivity between its mission computer and its primary sensors and weapons systems using Fibre Channel but may also have many legacy subsystems connected via MIL-STD-1553B. External communications, such as radios, are often limited to voice and a number of highly secure data links used to share data with other aircraft and surface ships within the local tactical environment. Such platform systems typically use unique internal data structures and maintain physical separation of mission data and sensor video.  This makes them unsuited to an Internet-like communications environment without extensive modification to their application software packages.

IPv6 gateway
The most likely initial steps will be to incorporate IPv6 by means of a gateway. This will consist typically of an intelligent subsystem incorporating a switch with a high-bandwidth external connection to the GIG. Other connections to the switch will be the platform’s sensors and its combat or mission system (Figure 1), offering only filtered views of the total information content available locally. It is likely that in addition to newer subsystems designed specifically with IPv6, many legacy pieces of equipment will be connected to the gateway, probably a mix of older IPv4 systems and subsystems using 100 Mbps or1 Gbps Ethernet in copper or fiber. Additionally, such a gate-way could be used to connect further legacy subsystems using MIL-STD-1553B or RS-485. For these legacy connections, the gateway needs to provide translation and support for the upper layers of the communications model in order to transfer any meaningful information.

Figure 1



Small platforms such as an armored vehicle may have only one gateway; larger platforms such as a Naval vessel may have many. The ideal way to implement such a gateway is as a COTS-based embedded subsystem with an IPv6-capable Ethernet switch and whatever legacy interfaces might be required to connect to the older subsystems. IPv6 can handle IPv4 traffic through its network though it retains the limitations of IPv4, reducing the need to replace or upgrade every existing subsystem for compliance.

Platform-level switched fabrics
But Ethernet and IPv6 are not just limited to the interplatform network domain of the GIG. Within platforms, there is growing demand for high-speed switched fabrics typified by Fibre Channel, Serial RapidIO, and PCI Express. These are used to enable data and resource sharing between multiple processors of a mission or combat system and the many subsystems making up the complete platform. These fabrics are usually characterized by their high line speeds (>1 Gbps) and low latency, which are both required for real-time, deterministic operation of the platform’s system. Ethernet will have the capability and latency to become a platform’s primary switched fabric. This reflects best practice in the commercial and telecommunications worlds, where Ethernet is firmly established as the de facto standard.

Hence a number of COTS vendors such as Curtiss-Wright Controls Embedded Computing, Radstone, and GE Fanuc Embedded Systems have introduced IPv6-capable Ethernet switches into their product portfolios. These switches offer built-in flexibility to support a number of physical connections and line speeds and include a processor for local network management functions. COTS switches are available in many formats including VME and CompactPCI, both of which are ideal for implementing gateway functions or intraplatform networks in deployed military applications. Typical of these is GE Fanuc’s RM921 (Figure 2) managed VME Ethernet switch with copper or fiber connections, 12 or 24 ports with support for IPv6. This product line is soon to be complemented with a next-generation managed switch offering much improved performance. Based upon the latest Broadcom devices, IPv6’s lower protocol layers are handled directly by hardware for lower latency and improved throughput.

Reaching the heart
Bringing effective Ethernet communi-cations to a force on the move will itself be a challenge, requiring vastly more wireless bandwidth than is available today; however, the intention behind the introduction of IPv6 is also to take communications deep into the heart of platforms, their systems, and subsystems. This will facilitate not only the sharing of data, but may also permit the operation and control of sensors, weapons, propulsion, and navigation systems from any remote location or even multiple locations and users. This migration of intelligence and control out of a deployed platform to a war fighter’s console could make today’s concept of an “onboard embedded intelligent subsystem” redundant, being replaced by a population of simple “remote terminals” instead.

This level of intrusion could well be seen first in small UAVs and Unmanned Combat Aerial Vehicles (UCAVs). In these vehicles, the volume of sensor data that could be acquired requires massive off-board computing resources to process and assimilate into the tactical situation.  As a result, the vehicle’s mission could be redirected in real time as situations develop. This also offers the potential for security vulnerabilities, but intrusion will inevitably be required anyway for software maintenance and network management just like any other Information Technology (IT) system. While network security will be enhanced by IPv6’s encryption, it will still rely heavily on secure, partitioned operating systems such as ARINC-653 and MILS for protection.

DoD committed to switch
IPv6 has been selected and will be implemented by the DoD, eventually finding a place in every platform, touching most embedded systems in some form or another within the next few years. It may even radically change the way these embedded systems are implemented. Ethernet switch device technology is on the fast track for more performance through hardware execution of the protocol, fueled by the telcos’ desire for more payload through their networks and the division of their services by quality requirements. The DoD will benefit from this rapid growth as will COTS vendors, such as GE Fanuc, and their customers by offering ultra-competitive, mainstream technology solutions for gateways, switched fabrics for platform networks and, eventually, fully integrated systems and subsystems incorporating IPv6.

For more information, contact Duncan at [email protected].


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