Optimization problems in correlated networks

Background Solving the shortest path and min-cut problems are key in achieving high-performance and robust communication networks. Those problems have often been studied in deterministic and uncorrelated networks both in their original formulations as well as in several constrained variants. However, in real-world networks, link weights (e.g.,...

A measurement study of DNSSEC misconfigurations

DNSSEC offers protection against spoofing of DNS data by providing origin authentication, ensuring data integrity and authentication of non-existence by using public-key cryptography. Although the relevance of securing a technology as crucial to the Internet as DNS is obvious, the DNSSEC implementation increases the complexity of the deployed...

A Pragmatic Approach to Impairment Awareness in Optical Networks

The points-of-presence of optical networks are interconnected by photonic paths capable of carrying Terabits of data. However, signals along those photonic paths accumulate transmission impairments and thus can be unreadable at the receiver if the accumulated impairments are too high. Our contributions in this paper are three-fold: (1) we...

Fast Recovery in Software-Defined Networks

Although Software-Defined Networking and its implementation OpenFlow facilitate managing networks and enable dynamic network configuration, recovering from network failures in a timely manner remains non-trivial. The process of (a) detecting the failure, (b) communicating it to the controller and (c) recomputing the new shortest paths may result...

Critical regions and region-disjoint paths in a network

Due to the importance of communication networks to society, it is pertinent that these networks can withstand failures. Improving the robustness of a network usually requires installing redundant resources, which is very costly. Network providers are consequently less inclined to take robustness measures against failures that are unlikely to...

Finding critical regions in a network

It is important that our vital networks (e.g., infrastructures) are robust to more than single-link failures. Failures might for instance affect a part of the network that resides in a certain geographical region. In this paper, considering networks embedded in a two-dimensional plane, we study the problem of finding a critical region - that is,...

Generating graphs that approach a prescribed modularity

Modularity is a quantitative measure for characterizing the existence of a community structure in a network. A network's modularity depends on the chosen partitioning of the network into communities, which makes finding the specific partition that leads to the maximum modularity a hard problem. In this paper, we prove that deciding whether a...

Generating graphs that approach a prescribed modularity