Network Breakdown – Destruction of Telecommunications
The breakdown of essential communications is one of the most widely shared characteristics of all disasters. Whether partial or complete, the failure of telecommunications infrastructure leads to preventable loss of life and damage to property, by causing delays and errors in emergency response and disaster relief efforts.
Yet despite the increasing reliability and resiliency of modern telecommunications networks to physical damage, the risk associated with communications failures remains serious because of growing dependence upon these tools in emergency operations.
Physical Destruction of Telecommunications Infrastructure
The most common and well-documented failures in recent disasters has been the physical destruction of Telecommunications infrastructure. Because of the time and funding needed to repair or replace systems, service disruptions caused by physical destruction also tend to be more severe and last longer than those caused by by disconnection or congestion.
As “the most complicated machine ever constructed by human beings,” historically the telephone system has been highly vulnerable to physical destruction during disaster. Earthquakes and severe weather can sever cables and flood underground equipment.
Wartime & Terrorism
During wars, these systems are usually the first sites to be targeted. The destruction of telecommunications networks as a battlefield tactic dates back to the first use of the telegraph in the U.S. Civil War. The fragility of telecommunications networks is due to the fact that historically, these systems have not had a high degree of redundancy.
The telephone network, for example, utilizes a branching structure in which destruction of a single network segment can disconnect entire neighborhoods instantaneously. Cities rarely escape even highly localized disasters without at least some physical damage to the telephone network.
The September 11 attacks caused collateral damage to an important telephone routing hub near the World Trade Center, disconnecting large portions of lower Manhattan from the telephone network.
High winds in hurricanes and tornadoes, icing in snowstorms, and motion from seismic events all wreak havoc on fragile overhead telephone lines. Underground fires crippled Internet communications on the east coast after the 2001 rail tunnel fire in Baltimore, and severely disrupted signaling in the New York City subway system.
Newer telecommunications networks are designed to be more resilient to physical destruction. The development of what would later be called the Internet, starting in the early 1970s, introduced a new philosophy to the design and operation of telecommunications networks.
Through both increased redundancy in network connections, and advanced routing techniques to circumvent damaged portions, so called “packet switched” networks can suffer severe damage before portions of the network become disconnected.
The remarkable survivability of IP networks was convincingly demonstrated during one major urban conflict, the 1999 NATO bombing of Belgrade.
While major telecommunications facilities were indeed destroyed early on by targeted strikes, Internet service providers were quickly able to fall back to a more decentralized array of secondary links – satellite links, cellular networks, and even amateur packet radio.
Yet despite its potential for resiliency, the Internet is not invulnerable. In fact, as ongoing research has shown, a handful of key interconnection facilities (“telco hotels”) located in majors cities present major points of vulnerability for Internet communications.
At the local level, Internet service for small businesses and homes is still largely delivered over the old, non-redundant copper wire of the telephone and cable television networks.
Wireless Resilience
Wireless links, whose links are constructed out of intangible electromagnetic radiation, reduce some of the vulnerability of wired networks. Yet as recent disasters have shown, they too are vulnerable to physical destruction. However, wireless networks have a high degree of variability in their vulnerability to physical destruction of nodes, and the loss of service that results.
Broadcasting facilities are typically centralized at the metropolitan scale, making them extremely vulnerable. The destruction of One World Trade Center, where many television and radio broadcast antennas were located, disrupted the broadcast capabilities of numerous media outlets.
Newer wireless networks are following the general trend towards more decentralized structures. The cellular telephone network is centralized at a smaller neighborhood scale in major cities.
Thus the destruction of antenna sites typically only reduces service in a limited area. For example, McCaw Cellular lost 2 of its 400 cell sites in the Northridge earthquake, resulting in only isolated service disruptions.
As the most sophisticated and fragile urban infrastructure, telecommunications networks are damaged in nearly every major urban disaster. However, it is not the size of the disaster that is the determining factor, but how its geography of destruction coincides with both old and new facilities for communications.
