# Network Challenges

## Contents |

## [Neumayer-Zussman-Cohen-Modiano-2011 (doi) .]

S. Neumayer, G. Zussman, R Cohen, E. Modiano

“Assessing the Vulnerability of the Fiber Infrastructure to Disaster”,

*IEEE/ACM Transactions on Networking*, April 2011, pp. 1–1

**ResiliNets Keywords: ** network challenges

**Keywords:** Electromagnetic pulse (EMP), ﬁber-optic, geographically correlated failures, network survivability

**Abstract:** “Communication networks are vulnerable to natural disasters, such as earthquakes or floods, as well as to physical attacks, such as an electromagnetic pulse (EMP) attack. Such real-world events happen in specific geographical locations and disrupt specific parts of the network. Therefore, the geographical layout of the network determines the impact of such events on the network's connectivity. In this paper, we focus on assessing the vulnerability of (geographical) networks to such disasters. In particular, we aim to identify the most vulnerable parts of the network. That is, the locations of disasters that would have the maximum disruptive effect on the network in terms of capacity and connectivity. We consider graph models in which nodes and links are geographically located on a plane. First, we consider a simplistic bipartite graph model and present a polynomial-time algorithm for finding a worst-case vertical line segment cut. We then generalize the network model to graphs with nodes at arbitrary locations. We model the disaster event as a line segment or a disk and develop polynomial-time algorithms that find a worst-case line segment cut and a worst-case circular cut. Finally, we obtain numerical results for a specific backbone network, thereby demonstrating the applicability of our algorithms to real-world networks. Our novel approach provides a promising new direction for network design to avert geographical disasters or attacks.”

**Notes:**

## [Neumayer-Zussman-Cohen-Modiano-2008 (doi) .]

S. Neumayer, G Zussman, R Cohen, E. Modiano

“Assessing the Impact of Geographically Correlated Network Failures”,

*IEEE Military Communications Conference*, Nov. 2008, pp. 1–6

**ResiliNets Keywords: ** network challenges

**Keywords:** Network survivability, geographic networks, Internet, cut capacity, network design, Electromagnetic Pulse(EMP)

**Abstract:** “Communication networks are vulnerable to natural disasters, such as earthquakes or floods, as well as to human attacks, such as an electromagnetic pulse (EMP) attack. Such real-world events have geographical locations, and therefore, the geographical structure of the network graph affects the impact of these events. In this paper we focus on assessing the vulnerability of (geographical) networks to such disasters. In particular, we aim to identify the location of a disaster that would have the maximum effect on network capacity. We consider a geometric graph model in which nodes and links are geographically located on a plane. Specifically, we model the physical network as a bipartite graph (in the topological and geographical sense) and consider the set of all vertical line segment cuts. For that model, we develop a polynomial time algorithm for finding a worst possible cut. Our approach has the potential to be extended to general graphs and provides a promising new direction for network design to avert geographical disasters or attacks.”

**Notes:**

## [Neumayer-Modiano-2010 (doi) .]

S. Neumayer, E. Modiano

“Network Reliability With Geographically Correlated Failures”,

*Proceedings of the IEEE INFOCOM*, March 2010, pp. 1–9

**ResiliNets Keywords: ** network challenges

**Keywords:** attacks, fiber-optic networks, geographical disasters, geographically correlated failures, network failures, network reliability

**Abstract:** “Fiber-optic networks are vulnerable to natural disasters, such as tornadoes or earthquakes, as well as to physical failures, such as an anchor cutting underwater fiber cables. Such real-world events occur in specific geographical locations and disrupt specific parts of the network. Therefore, the geography of the network determines the effect of physical events on the network's connectivity and capacity. In this paper, we develop tools to analyze network failures after a `random' geographic disaster. The random location of the disaster allows us to model situations where the physical failures are not targeted attacks. In particular, we consider disasters that take the form of a `random' line in a plane. Using results from geometric probability, we are able to calculate some network performance metrics to such a disaster in polynomial time. In particular, we can evaluate average two-terminal reliability in polynomial time under `random' line-cuts. This is in contrast to the case of independent link failures for which there exists no known polynomial time algorithm to calculate this reliability metric. We also present some numerical results to show the significance of geometry on the survivability of the network and discuss network design in the context of random line-cuts. Our novel approach provides a promising new direction for modeling and designing networks to lessen the effects of geographical disasters or attacks.”

**Notes:**

## [Neumayer-Zussman-Cohen-Modiano-2009 (doi) .]

S. Neumayer, G. Zussman, R. Cohen, E. Modiano

“Assessing the Vulnerability of the Fiber Infrastructure to Disasters”,

*Proceedings of the IEEE INFOCOM*, April 2009, pp. 1566–1574

**ResiliNets Keywords: ** network challenges

**Keywords:** communication networks, fiber infrastructure, geographical layout, natural disasters, network connectivity, vulnerability, worst-case line segment

**Abstract:** “Communication networks are vulnerable to natural disasters, such as earthquakes or floods, as well as to physical attacks, such as an Electromagnetic Pulse (EMP) attack. Such real- world events happen in specific geographical locations and disrupt specific parts of the network. Therefore, the geographical layout of the network determines the impact of such events on the network's connectivity. In this paper, we focus on assessing the vulnerability of (geographical) networks to such disasters. In particular, we aim to identify the most vulnerable parts of the network. That is, the locations of disasters that would have the maximum disruptive effect on the network in terms of capacity and connectivity. We consider graph models in which nodes and links are geographically located on a plane, and model the disaster event as a line segment or a circular cut. We develop algorithms that find a worst- case line segment cut and a worst-case circular cut. Then, we obtain numerical results for a specific backbone network, thereby demonstrating the applicability of our algorithms to real-world networks. Our novel approach provides a promising new direction for network design to avert geographical disasters or attacks.”

**Notes:**

## [Cohen-1986 (doi) .]

L.G. Cohen

“Trends in U.S. Broad-Band Fiber Optic Transmission Systems”,

*IEEE JSAC*, vol.4, #4, July 1986, pp. 488–497

**ResiliNets Keywords: ** network challenges, physical topology

**Keywords:** Optical fiber communication

**Abstract:** “Fiber optic media are rapidly penetrating the telecommunications network. They are used as undersea and terrestial trunk lines, central-office loops, optical data links, and will eventually be included within the distribution plant which connects directly into individual premises. The rapid implementation of lightwave systems is occurring because the high bandwidths and low losses of optical fibers enable broad-band communication services to be provided between widely spaced repeaters and also allows users to upgrade currently installed systems to meet future needs. This paper will describe current applications and show how future trends will depend upon the continuing evolution of lightwave components and optical fiber designs.”

**Notes:**

## [Kaiser-Midwinter-Shimada-1987 (doi) .]

P. Kaiser, J. Midwinter, S. Shimada

“Status and future trends in terrestrial optical fiber systems in North America, Europe, and Japan”,

*IEEE Communications Magazine*, vol.25, #10, Oct. 1987, pp. 8–13

**ResiliNets Keywords: ** network challenges, physical topology

**Keywords:** Optical fiber communication

**Abstract:** “.”

**Notes:**