Network security is one of major concerns for any business or organization transporting sensitive and confidential information over network. Such network security concerns involve lowest network layer, typically referred to as physical layer (layer one), as well as higher software layers of networking protocols. Most of interception activity by outside intruders occurs within higher protocol software layers. Password protection or data encryption are examples of counter measures to protect network from outside and unwanted tampering. Intrusion of physical layer itself can be another concern for network operators, although it is a far less likely target for unauthorized access to networking data. This can be a threat if information is transported over a copperbased infrastructure that can be easily intercepted, but optical wireless transmissions are among most secure connectivity solutions, regarding network interception of actual physical layer. LightPointe’s optical wireless networking equipment is based on physical layer transport. This white paper discusses security aspects involving physical layer.
Optical Wireless Systems and Network Security
With its cost-effective and high-bandwidth qualities, optical wireless products operating in near infrared wavelength range are an alternative transport technology to interconnect highcapacity networking segments. These optical wireless products, based on free-space optics (FSO) technology, are license-free worldwide. Optical wireless system installations are very simple, and equipment requires very little maintenance. These features make optical wireless solutions appealing to end-users and service providers globally. As a result, number of optical wireless system installations to for enterprise, cellular, and metropolitan area network traffic demands has increased significantly—even during recent telecommunications sector slowdown.
Because optical wireless systems send and receive data through air between remote networking locations, network operators and administrators are naturally concerned about security aspects. One of main reasons for this concern is based on fact that wireless networking solutions is a category in which security and interference problems are very common in radio frequency (RF) or microwave-based communication systems. Such concerns are not valid for optical wireless systems.
Optical wireless systems operate in near infrared wavelength range slightly above visible spectrum. Therefore, human eye cannot visibly see transmission beam. The wavelength range around 1 micrometer that is used in optical wireless transmission systems is actually same wavelength range used in fiber-optic transmission systems. The wavelength range around 1 micrometer translates into frequencies of several hundred terahertz (THz). These frequencies are significantly (roughly three to four orders of magnitude) higher than highest frequencies used in commercially available microwave communications systems operating around 40 GHz. This difference in frequency of operation is one of main reasons why optical wireless systems belong into equipment category of optical communication systems first rather than wireless, RF or microwave, transmission solutions. While typical RF and microwave antennas used to interconnect two remote networking locations in a point-to-point architecture spread out radiation over angles between 5 and 25 degrees, optical wireless systems use very narrow beams that are typically much less than 0.5 degrees. For example, a radial beam pattern of 10 degrees roughly corresponds to a beam diameter of 175 meters at a distance of 1 kilometer from originating source, whereas a beam of 0.3 degrees divergence angle typically used in optical wireless systems corresponds to a beam diameter of 5 meters at same distance.1 This wide spreading of beam in microwave systems, combined with fact that microwave antennas launch very high power level is primary reason for security concerns. An outside intruder can easily intercept beam or power reflected from target location and pick up sensitive network information by using a “spectral scanner” tuned to specific RF or microwave transmission frequency. To overcome these security concerns, microwave industry uses wireless encryption protocols (WEP) to protect transmission path from being intercepted. Although it is extremely unlikely that it is possible to break into a sophisticated encryption code, there is always concern that it can be done.