Energy efficiency is one of the great technological challenges of our times. Recently, the concerns for the environmental consequences of the huge rate with which energy is consumed is leading to the awareness that electricity consumption and waste should be reduced in all sectors. The ICT (Information and Communication Technology) sector makes no exception, since it is becoming a major component of the worldwide energy consumption budget.  

In the last decade, there have been radical changes in both the nature of the mechanisms used for Internet content distribution, and the type of content delivered. On the one hand, Peer-to-Peer (P2P) based content distribution has matured. On the other hand, there has been a tremendous growth in video traffic. The goal of my work is to characterize these emerging trends in content distribution and understand their implications for Internet Service Providers (ISP) and users. Such characterization is critical given the predominance of P2P and video traffic in the Internet today and can enable further evolution of content delivery systems in ways that benefit both providers and users.  

Mobile networks allow accessing and sharing information everywhere, but current infrastructures are limited by their legacies from circuit-switched networks. Although mobile ad-hoc networks (MANETs) solve many of these shortcomings, they face important challenges regarding routing and security. Localized geographic forwarding schemes are very promising for handling the routing challenge even in large multihop wireless networks, since they enable nodes to take routing decisions based only on information about their neighbors.

The use of centralized mobility management approaches – such as Mobile IPv6 – poses some difficulties to operators of current and future networks, due to the expected large number of mobile users and their exigent demands. All this has triggered the need for distributed mobility management alternatives, that alleviate operators’ concerns allowing for cheaper and more efficient network deployments.  

Improving the energy-efficiency of core routers is important for ISPs and equipment vendors alike. We tackle this problem by focusing on packet buffers in backbone router line-cards. We broadly classify the talk into two parts – an evolutionary approach and a clean-slate design. In the former, we propose a simple power saving mechanism that turns buffers on/off to save energy. Our scheme can be incrementally deployed today and requires minimal changes to existing line-card design.

Disruptive events such as large-scale power outages, undersea cable cuts, or Internet worms could cause the Internet to deviate from its normal state of operation. This deviation from normalcy is what we call the impact on the Internet, which we also refer to as an "Internet earthquake."    

The media access control (MAC) layer of the IEEE 802.11 standard specifies a set of parameters that regulate the behavior of the wireless stations when accessing the channel. Although the standard defines a set of recommended values for these parameters, they are statically set and do not take into account the current conditions in the wireless local area network (WLAN) in terms of, e.g., number of contending stations and the traffic they generate, which results in suboptimal performance

A frequent problem in settings where a unique resource must be shared among users is how to resolve the contention that arises when all of them must use it, but the resource allows only for one user each time. The application of efficient solutions for this problem spans a myriad of settings such as radio communication networks or databases.

Carrier Sense Multiple Access with Enhanced Collision Avoidance (CSMA/ECA) is a distributed MAC protocol that allows collision-free access to the medium in WLAN. The only difference between CSMA/ECA and the well-known CSMA/CA is that the former uses a deterministic backoff after successful transmissions. Collision-free operation is reached after a transient state during which some collisions may occur. This article shows that the duration of the transient state can be shortened by appropriately setting the contention parameters. Standard absorbing Markov Chain theory is used to describe the behaviour of the system in the transient state and to predict the expected number of slots to reach the collision-free operation.

The scalability issues the global routing system has been experienc- ing over the past years have raised serious concerns in the Internet community. One of the main culprits for the rapidly growing BGP routing table is the defragmentation process of the address blocks allocated to ASes, also known as prefix deaggreation. The Internet is a complex system and understanding its behavioural evolution is certainly a challenging task. For this reason, the use of eco- nomic models can provide intuitive explanations of the complex interactions between networks that result in the aforementioned phenomenon of prefix deaggreation. In this paper, we propose a game theoretic model to analyze the incentives behind the deag- gregating strategies of the networks. Announcing more-specific prefixes in the Internet impacts the size of the global routing table and increases the network operators’ capital expenditure for rout- ing equipment capable of sustaining the growing Internet. How- ever, we prove that the ASes are driven by fundamental economic reasons towards this type of apparently harming behaviour. We find that by announcing more prefixes the originating network achieves a more predictable traffic pattern and reduces the peak levels of bandwidth consumption. We show that this happens because, both in the equilibrium point and the social welfare point, the cost re- duction achieved by smoothing the traffic distribution outweighs the additional cost incurred by the routing table expansion.