Mapping the Internet is a major challenge for network researchers. It is the key to building a successful modeling tool able to generate realistic graphs for use in networking simulations. In this paper we provide a detailed analysis of the inter-domain topology of the Internet. The collected data and the resulting analysis began in November 1997 and cover a period of two and a half years. We give results concerning major topology properties (nodes and edges number, average degree and distance, routing policy, etc.) and main distributions (degree, distance, etc.). We also present many results about the trees of this network. The evolution of these properties is reviewed and major trends are highlighted. We propose some empirical laws that match this current evolution. Four new power-laws concerning the number of shortest paths between node pairs and the tree size distribution are provided with their detailed validation.

The potential for being the target of Denial of Service (DoS) attacks is one of the most severe security threats on the Internet. Attackers have been modifying their attack format over the years, damaging specific conditions of operating systems and protocols in an attempt to deny or diminish the quality of the service provided to legitimate users. Nowadays, attacks are stealthier and mimic legitimate user traffic in such a way that detection mechanisms against High-rate DoS attacks are no longer sufficient. This evolving type of attack, known as LDoS (Low-rate Denial of Service) attacks, has the potential to produce more damage than its predecessor due to its stealth nature and the lack of suitable detection and defense methods. This survey summarizes and complements previous studies and surveys related to this specific type of attack. First, we propose a taxonomy of the LDoS attacks, which were divided into three broad categories based on their modus operandi: QoS attacks, Slow rate attacks, and Service queue attacks. Next, we detail numerous detection mechanisms and counter-measures available against eight types of LDoS attacks. More specifically, we describe the methods used to throttle the attack traffic. Finally, we provide a feature comparison table for some existing attack tools. This survey aims at providing an extensive review of the literature for helping researchers and network administrators find up-to-date knowledge on LDoS attacks.

Creating a network topology is the first step in building a scenario for a network protocol simulation. The simulation results usually depend on the topology layout, especially for routing and multicasting protocols. Therefore the topology used should be generated with the highest possible accuracy. In particular, protocols designed for the Internet should be simulated over Internet-like topologies. Many topology generators currently exist but the discovery of power laws in the Internet has brought new constraints upon the generated topologies. We introduce a flexible novel way to create Internet-like topologies. It is based on an algorithm that performs a sampling on a measured Internet map. The created topologies accurately comply with the newly found power laws as well as other more common topology properties such as the average path length.