The motivation for this work comes from a desire to improve resilience of mission critical cyber enabled systems
including those used in critical infrastructure domains such as cyber, power, water, fuel, financial, healthcare,
agriculture, and manufacturing. Resilience can be defined as the ability of a system to persistently meet its performance
requirements despite the occurrence of adverse events. Characterizing the resilience of a system requires a clear
definition of the performance requirements of the system of interest and an ability to quantify the impact on performance
by the adverse events of concern. A quantitative characterization of system resilience allows the resilience requirements
to be included in the system design criteria. Resilience requirements of a system are derived from the service level
agreements (SLAs), measures of effectiveness (MOEs), and measures of performance (MOPs) of the services or
missions supported by the system. This paper describes a methodology for designing resilient systems. The components
of the methodology include resilience characterization for threat models associated with various exposure modes,
requirements mapping, subsystem ranking based on criticality, and selective implementation of mitigations to improve
system resilience to a desired level.
The advent of cyber threats has created a need for a new network planning, design, architecture, operations, control,
situational awareness, management, and maintenance paradigms. Primary considerations include the ability to assess
cyber attack resiliency of the network, and rapidly detect, isolate, and operate during deliberate simultaneous attacks
against the network nodes and links. Legacy network planning relied on automatic protection of a network in the event
of a single fault or a very few simultaneous faults in mesh networks, but in the future it must be augmented to include
improved network resiliency and vulnerability awareness to cyber attacks. Ability to design a resilient network requires
the development of methods to define, and quantify the network resiliency to attacks, and to be able to develop new
optimization strategies for maintaining operations in the midst of these newly emerging cyber threats. Ways to quantify
resiliency, and its use in visualizing cyber vulnerability awareness and in identifying node or link criticality, are
presented in the current work, as well as a methodology of differential network hardening based on the criticality profile
of cyber network components.
Results of a field demonstration of an air-to-ground communication link using an airborne bare
optical fiber are presented. The demonstration was conducted by the Johns Hopkins University,
Applied Physics Laboratory at the TCOM, L.P. Test Facility in Elizabeth City, NC in May 2006
using a 38 m, tethered aerostat raised to an altitude of 2100 ft. A bare, single mode optical fiber
attached between the aerostat and its mooring station was evaluated as an optical link for several
hours. Wavelength Division Multiplexed channels operating in the 1550 nm band with data rates of 1
and 10 Gbps were tested to achieve error free data transfers. A separate, continuous wave channel
was also multiplexed for performance monitoring. BER vs. link power measurements and eye
diagrams will be analyzed for data transfer performance over the airborne bare optical fiber.
A free-space optical (FSO) communication demonstration was conducted with JHU/APL and AOptix at the TCOM Test Facility in Elizabeth City, NC in May 2006. The primary test objective was to evaluate the performance of an FSO link from a fiber-tethered aerostat to a ground platform at effective data rates approaching 100 Gigabits/sec using wavelength division multiplexing (WDM) techniques. (Multiple optical channels operating near 1550 nm were modulated at data rates of 1, 10 and 40 Gbps). The test was conducted with a 38 meter aerostat raised to an altitude of 1 km and a ground platform located 1.2 km from the aerostat (limited by property boundary). Error free data transfers of 1.2 Terabits in 30 seconds at 40 Gbps were demonstrated. The total data transferred during the test was greater than 30 Terabits with an average BER of 10-6 without any forward error correction (FEC) coding.
Optical communications technologies are being actively explored by the defense and security communities as a potential solution to alleviate bandwidth bottlenecks and to provide covert, jam resistant communications without spectrum restrictions. While static fiber-optic networks are widely deployed in the Department of Defense (DoD) communications network, the integration of wireless, free space optical (FSO) communications technology is required to provide end-to-end high bandwidth paths to support mobile defense and security operations. This paper presents an analysis of inherent benefits of optical wireless communications technologies in enabling net-centric applications and discusses specific technology and architectural challenges that need to be overcome before these technologies can be seamlessly integrated in the Global Information Grid (GIG) to fully realize the net-centric vision.
A large number of communications technologies co-exist today in both civilian and military space with their relative strengths and weaknesses. The information carrying capacity of optical fiber communication, however, surpasses any other communications technology in use today. Additionally, optical fiber is immune to environmental effects and detection, and can be designed to be resistant to exploitation and jamming. However, fiber-optic communication applications are usually limited to static, pre-deployed cable systems. Enabling the fiber applications in dynamically deployed and ad-hoc conditions will open up a large number of communication possibilities in terrestrial, aerial, and oceanic environments. Of particular relevance are bandwidth intensive data, video and voice applications such as airborne imagery, multispectral and hyperspectral imaging, surveillance and communications disaster recovery through surveillance platforms like Airships (also called balloons, aerostats or blimps) and Unmanned Aerial Vehicles (UAVs).
Two major considerations in the implementation of airborne fiber communications are (a) mechanical sustainability of optical fibers, and (b) variation in optical transmission characteristics of fiber in dynamic deployment condition. This paper focuses on the mechanical aspects of airborne optical fiber and examines the ability of un-cabled optical fiber to sustain its own weight and wind drag in airborne communications applications. Since optical fiber is made of silica glass, the material fracture characteristics, sub-critical crack growth, strength distribution and proof stress are the key parameters that determine the self-sustainability of optical fiber. Results are presented in terms of maximum self-sustainable altitudes for three types of optical fibers, namely silica-clad, Titania-doped Silica-clad, and carbon-coated hermetic fibers, for short and long service periods and a range of wind profiles and fiber dimensions.
This paper identifies the sources of inefficiency for both transparent and opaque networks. The disparities in strategies for optimizing transparent and opaque networks are discussed. Strategies used for optimizing transparent optical networks include sub-wavelength edge grooming, optical access techniques with hub grooming, astute wavelength allocation and reuse, selective wavelength conversion and re-grooming preferably at the natural regeneration sites, use of tunable devices, multi-bitrate and multi-reach transmission in the same infrastructure, and system upgradeability from point-to-point to transparent networks.