Growing Vulnerability of the Public Switched Networks: Implications for National Security Emergency Preparedness (1989)

The Cuban Missile Crisis of October 1962 brought home to policy makers the importance of communications resources during emergency conditions. Problems encountered during that two-week period led President Kennedy to establish what is now known as the National Communications System (NCS). While few national security communications initiatives were undertaken in the first 15 years, there have been numerous national security emergency preparedness (NSEP) initiatives during the past 10 years. The more important ones are described herein to illustrate progress made and to provide a baseline for future work. In 1979 President Carter issued Presidential Directive 53 (PD 53), a national security telecommunications policy directive that stated that survivable communications is a necessary component of national security (Executive Office of the President, 1979). PD 53 placed heavy reliance on the national telecommunications infrastructure supplied by the common carriers to supply communications for NSEP programs.

The divestiture of Bell System components raised genuine concerns in the national security community about the effect of the breakup on NSEP. In 1982, and responding to such concerns, the divestiture court ordered the establishment of a centralized support

organization to serve as a single point of contact for the NSEP activities of the seven regional companies. The organization, known today as Bell Communications Research (Bellcore), provides staff resources and technical assistance, and serves as an interface between the regional companies and the federal government. In March of 1982 NCS officials met with telecommunications industry leaders to consider approaches for joint industry-government planning for NSEP communications. The result was the establishment of the National Security Telecommunications Advisory Committee (NSTAC) by Executive Order (EO) 12382 (Executive Office of the President, 1982). The purpose of the NSTAC is to advise the President and the Secretary of Defense (who is the Executive Agent for the NCS) on NSEP telecommunications matters.

This action was followed in 1983 by the issuance of National Security Decision Directive (NSDD) 97 (Executive Office of the President, 1983), which replaced PD 53. NSDD 97 stated that the nation’s domestic and international telecommunications resources are essential elements of U.S. national security policy and strategy, and that a survivable telecommunications infrastructure able to support national security leadership is a crucial element of U.S. deterrence. It went on to establish a steering group to oversee implementation and assigned specific responsibilities to the Manager of NCS, NSTAC, and federal departments and agencies.

In 1984, EO 12472 consolidated the assignment of NSEP telecommunications functions (Executive Office of the President, 1984). It provided a framework for planning, developing, and exercising federal government NSEP communications measures. It also established a means for providing advice and assistance to state and local governments, private industry, and volunteer organizations regarding their NSEP communications needs.

An early recommendation of the NSTAC was to establish a joint industry government coordinating center to assist in the initiation and restoration of NSEP telecommunications. The National Coordinating Center was established in January 1984 and has operated continuously since that time.

A related, and still ongoing, activity is the establishment of the Telecommunications Service Priority system. Recently approved by the Federal Communications Commission, it provides the regulatory, administrative, and operational system for authorizing and providing priority treatment of NSEP telecommunications services.

Finally, in December 1985, NSDD 201 was issued to ensure the

availability of resources necessary to achieve NSEP telecommunications objectives. This was an important step because it established funding responsibilities. Thus, a number of measures have been established to address the organizational, planning, and implementing structure for NSEP telecommunications. From that structure emerged the first NSEP National-Level Programs, which are described below (Bird, 1987).

The Commercial Satellite Interconnectivity (CSI) program uses surviving C-band commercial satellite resources to augment or reconstitute public switched network (PSN) interswitch trunking in a postattack environment (Williams, 1988). The program offers a major improvement in survivability at a relatively low cost.

There are about 19 C-band satellites that are candidates for use in the postattack environment. Even though commercial satellites are generally thought to be vulnerable to enemy attack, either by jamming or nuclear effects, it is assumed that one or more of these satellites will survive. As fax as the desirability of further hardening of satellites against radiation is concerned, assessments that take into account threat, the consequences of loss, the additional weight penalty on the spacecraft, and the additional costs involved have indicated that hardening beyond that already employed would not be warranted. Although the destruction of these satellites is possible, the task is not an easy one. In this case the enemy would have to destroy all 19 satellites. If any single satellite or two were to go intermittently quiet, the enemy’s targeting would become extremely difficult. Even if the enemy has a 0.9 probability of destroying any single satellite, the probability of destroying all is only 0.135. At this time there are no known antisatellite weapons (ASATs) that have the ability to destroy a geosynchronous satellite. By contrast, ASATs pose a demonstrated threat at low altitudes.

Various attack modes against geosynchronous satellites have been postulated, but evidence of such a development has been lacking. Among conceivable attacks are the following:

• On-orbit mines

• Command-link seizure, followed by a command causing a catastrophic action by the satellite

• Jamming, a temporary interruption unless sufficient power is used to “burn out” the input circuits of a transponder

• Direct physical attack from earth by missile or some other mechanism designed to “burn out” the solar arrays.

Thus, the probability of destruction of a commercial communications satellite (all at geosynchronous altitude) is very low. An illustrative assumption of 0.9 is perhaps excessively conservative. However, the thesis that the probabilities are such that some will survive, and should be considered in the planning process, is valid even with an excessively conservative assumption at the beginning. Thus, the payoff for parallelism here is significant. From this point of view, the survivability of commercial satellites as a whole may be underestimated.

To use this potential capability, the NCS National-Level Program must add whatever missing pieces are necessary to allow any single surviving satellite to constitute the “patch cords” between the surviving islands of communications after a major attack. In the plan, all the reconstituted spans are patched using T-1 links terminating at 4ESS switches. To implement the plan, the NCS provides the circuit under the CSI program from the common carrier’s switch location to the selected satellite “up-link” station location.

Phase I of CSI augments only the American Telephone and Telegraph Company’s interexchange carrier network. The program leases standby services. The NCS is initially concentrating on C-band coterminous U.S. (CONUS) earth station facilities, of which there are some 1,000 in the United States. C-band is used because it incorporates end-to-end standardization. All CONUS facilities follow the same frequency plan based on T-1 modems. Twenty T-1 channels fit into a 36-MHz transponder with intermodulation requirements met. Only satellites having encrypted telemetry, tracking, and control will be used by the NCS in accordance with national security guidelines. In Phase I, the NCS is planning to add 75 T-1 equivalent links to the system.

Mobile earth stations are feasible and technically viable. They would have much value but are costly; thus they are a “budget-permitting” issue in the federal government. The use of Ku band is also being studied. However, Ku-band satellite channels will be more difficult to implement because of a nonstandard channel allocation among the different satellites.

The Commercial Network Survivability (CNS) program provides a

limited number of links to connect user clusters to access points (Martens, 1987). CNS focuses on connecting isolated clusters of users to surviving portions of the PSN. The CNS may be thought of as providing the local connectivity to a user, whereas the CSI is the long distance network transmission patch. There are two program components: carrier interconnection (CI) and mobile transportable telecommunications (MTT).

The carrier interconnection concept is to improve connectivity between carriers so that damaged facilities can be bypassed. In addition, the use of existing government networks can be used for interconnection to improve the robustness of the PSN for NSEP users. The NCS has such a program under the CNS to demonstrate and implement a Federal Aviation Administration (FAA) and PSN interconnect in the Dallas-Fort Worth area, to be followed by further interconnects in Brockton, Massachusetts and Louisville, Kentucky in 1988 and 1989. Potentially, two FAA locations per month could be added to the program. The FAA-PSN interconnects will require modifications to routing tables, or require new routing tables to reflect the availability of these new connections. The FAA network is a “nailed-up,” or dedicated, private line arrangement, which it appears will use in-band signaling transmitted over the FAA microwave system. This interface with the PSN requires software and hardware to accommodate network control, but not through the signal transfer points.

The mobile transportable telecommunications capability augments PSN transmission for NSEP traffic. An early demonstration in the Colorado Springs area used older generation military radios as PSN “pipes” that passed voice and low-data-rate data traffic. The purpose was to evaluate and test system interfaces and verify the MTT concept and capability to support diverse users during adverse conditions. A more comprehensive exercise was conducted in California during October 1987, simulating an earthquake disaster. Transmission quality for voice was satisfactory over six tandem links; 2,400-bits/s data transmission was satisfactory over two links; and 1,200-bits/s data transmission was satisfactory over four links.

The Nationwide Emergency Telecommunications Service (NETS) is the NCS’s major National-Level Program. NETS is intended to

provide selected users with a highly survivable, inter agency, switched voice and data telephone service based on a distributed system of call controllers and making use of a nonstandard routing scheme designed to find any available route to a destination. NETS is described and analyzed fully in the previously published report of this committee (National Research Council, 1987).

Bird, J. 1987. National level national security emergency preparedness telecommunications. Presentation to the Commitee on Review of Switching, Synchronization and Network Control in National Security Telecommunications, Washington, D.C., December 8.

Executive Office of the President. 1979. National Security Telecommunications Policy. Presidential Directive 53. Washington, D.C.: U.S. Government Printing Office.

Executive Office of the President. 1982. President’s National Security Telecommunications Advisory Committee. Executive Order 12382. Washington, D.C.: U.S. Government Printing Office.

Executive Office of the President. 1983. National Security Telecommunications Policy. National Security Decision Directive 97. Washington, D.C.: U.S. Government Printing Office.

Executive Office of the President. 1984. Assignment of National Security and Emergency Preparedness Telecommunications Functions. Executive Order 12472. Washington, D.C.: U.S. Government Printing Office.

Martens, W. 1987. Commercial network survivability. Presentation to the Committee on Review of Switching, Synchronization and Network Control in National Security Telecommunications, Washington, D.C., December 8.

National Research Council. 1987. Nationwide Emergency Telecommunications Service for National Security Telecommunications. Washington, D.C.: National Academy Press.

Williams, L. 1988. National Communications System commercial satellite interconnect—sites and capabilities. Presentation to the Committee on Review of Switching, Synchronization and Network Control in National Security Telecommunications, Washington, D.C., January 20.