Communications systems are the backbone for much of the critical infrastructure within the United States and many of the other infrastructure components are completely dependent on communications systems to perform their missions. The communications sector provides the basis for information exchange for all other sectors including voice, data, video, and Internet connectivity. As such, communications systems serve part in parcel with other key national security and emergency preparedness resources and are an important component of our overall national critical infrastructure. It is therefore incumbent to recognize the importance that communications has for national security policy and issues of homeland security. At the same time, it is important to recognize the key factors upon which the communications infrastructure is dependent. In this topic, the core principles of public safety communications form the basis for a discussion of the interdependencies of communications systems. In particular, the focus of this topic is the interdependencies between the communications sector and the national utility infrastructure.
One way of investigating the interdependencies of the communications architecture is to look at them from a critical infrastructure perspective. The National Infrastructure Protection Plan1 (NIPP) is intended to meet the requirements set forth by the President in Presidential Directive 72 (HSPD-7), Critical Infrastructure Identification, Prioritization, and Protection, and is an overarching approach for integrating the nation's Critical Infrastructure and Key Resources (CIKR) protection initiatives. One of the critical sectors within the CIKR is the Communications Sector3. In addition, the Energy Sector is comprised of the oil, gas, and electric power production, refining, storage and distribution facilities and the Water Sector includes all those facilities for fresh water and waste water management. These two sectors are administered by national or local public service commissioners.
The national protection plan highlights those sectors that are critical for national security and emergency preparedness and delineates measures to protect these resources. Similarly, the Communications Sector-Specific Plan details factors that are important for the protection of the communications sector. Alternatively, the National Association of Regulatory Utility Commissioners4 (NARUC) has published a set of Critical Infrastructure Technical Briefs that "...identify key strategies for our consideration as we meet ongoing challenges within each of the electricity, natural gas, water, and telecommunications sectors."5 The following diagram from the NARUC "Issue Paper on Critical Infrastructure Protection" shows many of the interdependencies for the utility "sector."6 It only partially illustrates the extent of the interdependencies between the utilities (electric power, oil and gas, water), and other sectors including communications, transportation, banking and finance, government services, transportation, and government services.
It is clear from this diagram that there is a great deal of interdependency between the Communications Sector and a number of the functionaries within the utility community. This diagram illustrates that almost all of the utilities have critical requirements for communications of some form. Alternatively, the communications community has a number of instances where they are dependent on the utilities. The remainder of the topic will highlight some of these issues.
Without question, the dominant dependency for the Communications Sector is electrical power. Every node in the communications architecture - whether it is a switching center, radio relay site, cell site, other remote site, or any other facility - relies on electrical power for its operation. Electricity powers the communications systems equipment, the central control/management/operating systems, and even the environmental control systems surrounding the communications equipment. In most cases, the power to run the communications infrastructure is provided on a continual basis by the commercial power industry. As such, there is a direct and critical link between the electrical power networks and the communications networks that are dependent on them.
On the other hand, the electrical power industry is dependent upon the communications providers for inter-facility communications, management and control of operations, and management of facilities. Although many power production and distribution facilities have their own organic communications facilities that utilize the power grid infrastructure, nevertheless, the power industry is still reliant on commercial communications facilities for transferring information.
In order to overcome any loss of commercial power, most communications locations have some form of alternative power capability inherent to the facility. This backup power is usually in the form of battery support for short duration power outages while larger facilities will subsequently utilize organic power generators to provide power until the commercial supplier is back on line. In both cases, the backup power capability is limited. First, batteries have only a short term life of approximately a few hours. Second, the local generators have a limited supply of fuel and must be resupplied depending on how long the generators must continue to operate.
A number of recent large scale power outages including the 2003 Northeast region blackout and Hurricane Katrina in 2005 have highlighted the strong interdependencies of the power and communications sectors. In response to these outages and the resulting studies done by the National Security Telecommunications Advisory Committee (NSTAC),7 in 2007 the National Communications System Committee of Principals (COP) established the Communications Dependency on Electrical Power Working Group (CDEP WG). The report of this working group found a number of conclusions and recommendations for the communications sector to address long term power outages and their impacts on the communications sector.8
The requirements for locally generated power suggest another dependency for the Communications Sector. Where it is necessary to generate power independently, the generators rely on some source of energy (water, fuel, etc.) to run the generators and this is usually a fossil fuel of some form usually diesel fuel. Thus, the reliance on the Energy Sector is critical for communications providers when there is a loss of commercial power and for as long as they must run their generators. This is not the norm though and usually the communications providers have limited on-hand supplies of fuel and rely on support agreements with local fuel and transportation providers to be able to support them in times of disaster, outages, or other emergencies. Closely related to fuel for generators is the requirement in many cases for natural gas or other fuels for heating purposes. Most communications facilities require environmental control to maintain nominal conditions for equipment to operate; this may require either water for cooling or gas for heating.
The potential dependency on water resources as a source for energy to generate power is most likely a small factor when compared to the use of water for other purposes. Access to water and the ability to handle waste water can be critical dependencies for communications providers. In most cases, the environmental control systems for communications facilities rely on fresh water for air conditioning and other environmental services. The availability of fresh water is therefore extremely important for facility owners and operators. Similarly, the ability to handle waste water from chillers or coolers is also important. Both the supply of fresh water and the handling of waste water are essential for most large scale communications facilities.
The next critical dependency for the Communications Sector as well as the other sectors is related to security of the facilities, but in this instance it is security of a different kind. Much of the communications infrastructure, including the SS7 control architecture itself, is vulnerable to cyber attack from either inside or outside of the network. The fact is that perhaps the largest vulnerability and dependency of the national communications infrastructure as well as the infrastructure for other sectors is on cyber security. The control of communications networks and all of its functional components are vulnerable to various degrees of cyber attacks on the software operating systems by either the idle hacker or the more malicious intruder participating in information warfare. This is also true of all of the networks within other sectors. In all instances, the networks must be protected and guarded from attack.
Finally, the communications infrastructure and the utilities are extremely dependent on the Information Technology Sector. This dependency is due to the reliance of the communications systems on the software that runs the control mechanisms of the operating systems, the management software, the billing software, and any number of other software packages that are used by industry. This also includes the Supervisory Control and Data Acquisition9 (SCADA) systems that provide the real time control mechanisms for most of the power and utility facilities.
From this discussion, it is clear that the any number of interdependencies could threaten one of the key components of our critical national infrastructure, the communications sector. These factors are the "realities" of the communications domain and go beyond just the core precepts of good communications systems development and design. Clearly, there is a great deal of interdependence on other outside factors that could threaten communications and other key resources. Without the active participation of each of these sectors, the key and essential facilities of the communications industry could be very vulnerable a fact that is not acceptable for the protection of our national interests.
1 For an overview of the NIPP and the accompanying programs, see the Department of Homeland Security's NIPP web site at http://www.dhs.gov/xprevprot/programs/editorial_0827.shtm .
2 For an overview and copy of HSPD-7, see http://www.dhs.gov/xabout/laws/gc_1214597989952.shtm .
3 See http://www.dhs.gov/xprevprot/programs/gc_1179866197607.shtm  for a discussion of the sector specific protection plans and see http://www.dhs.gov/xlibrary/assets/nipp-ssp-communications.pdf  for a copy of the May 2007 Communications Sector Specific Plan.
4 "NARUC is an association representing the State public service commissioners who regulate essential utility services, such as electricity, gas, telecommunications, water, and transportation, throughout the country. As regulators, our members are charged with protecting the public and ensuring that rates charged by regulated utilities are fair, just, and reasonable." The NARUC web site is at http://www.naruc.org/ .
5 See http://www.naruc.org/cipbriefs/ . "The purpose of these complementary and reinforcing papers is to provide public utility commissioners and other participants in the regulatory policy community with introductory overviews, suggested protocols, and additional resources on critical infrastructure protection issues."
7 See NSTAC's Report to the President on Telecommunications and Electric Power Interdependencies: The Implications of Long-Term Outages at http://www.ncs.gov/nstac/reports/2006/NSTAC_XXIX_Reports_082206.pdf .
8 Communications Dependency on Electric Power Working Group Report, "Long-Term Outage Study" National Communications System Committee of Principals, February 17, 2009.