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.

The technological advancement and information overload in recent years increased the popularity of Distributed Storage Systems where the data is replicated and maintained at multiple disks or servers residing at different network locations. While replication is sufficient to ensure data survivability, it raises an important question: "How can we efficiently maintain consistency among the replicas, despite system asynchrony and failures?"
 

As wireless ad hoc networking becomes more and more popular and ad hoc networks are used for an increasing number of applications, the integration of these networks in today's Internet, still mostly organized as a set of interconnected fixed and wired networks, becomes a key research field in the computer networking domain.

It is notoriously difficult to make distributed systems reliable. This becomes even harder in the case of the widely-deployed systems that are heterogeneous (multiple implementations) and federated (multiple administrative entities). The set of routers in charge of the Internet's inter-domain routing is a prime example of such a system.

In this paper we design, characterize in closed-form, and evaluate a new index rule for Markovian time-varying channels, which gives rise to a simple opportunistic scheduling rule for flow-level scheduling in wireless downlink systems. For user channels we employ the Gilbert-Elliot model with a flow-level interpretation: the channel condition follows a general two-state Markov chain with distinct probabilities of finishing the flow transmission.

Formally, the Internet inter-domain routing system is a collection of networks, their policies, peering relationships and organizational affiliations, and the addresses they advertize. It also includes components like Internet exchange points. By its very definition, each and every aspect of this system is impacted by BGP, the de-facto standard inter-domain routing protocol.

Internal BGP (iBGP) is used to distribute interdomain routes within a single ISP. The interaction between iBGP and the underlying IGP can lead to routing and forwarding anomalies. For this reason, several research contributions aimed at defining sufficient conditions to guarantee anomaly-free configurations and providing design guidelines for network operators.

In multi-hop networks, conventional unipath routing approaches force the data transmission to follow a fixed sequence of nodes. In this talk, we widen this path to create a corridor of forwarding nodes. Within this corridor, data can be split and joined at different nodes as the data travels through the corridor towards the destination node. To split data, decode-and forward OFDMA is used since with OFDMA, one can exploit the benefits of opportunistically allocating different subcarriers to different nodes according to their channel conditions. To avoid interference, each subcarrier is only allocated once per hop. For the presented scheme, the problem of optimizing the network throughput by means of resource and power allocation is formulated and two suboptimal algorithms are proposed to solve this problem with feasible effort. Simulations show that in multi-hop networks corridor-based routing using opportunistic forwarding outperforms conventional unipath routing approaches in terms of achievable throughput.

Wireless sensor network and wireless multimedia network technologies combined with interactive 3D virtual visualization can converge into really interesting and functional applications such as detailed real-time monitoring of environments, emergency response and preparedness, distributed collaborative training, and remote walkthroughs, just to name a few examples. With the recent advances in wireless communication, and the proliferation of portable computer and micro-sensor devices, we are witnessing a growing interest in using wireless multimedia sensor networks and collaborative virtual environment technologies for safety and security class of applications.

Vishal Misra together with Dan Rubinstein launched at the beginning of 2011 the company Silver Lining. This company is a very ambitious tech start-up arising from two professors of Columbia University, and has already attracted a lot of interest and a substantial amount of funding from investors. Silver Lining is developing a very advanced product in the area of content distribution networks that is expected to have high impact. Vishal Misra, co-founder and its current CEO, will give a first-hand account on the development of this interesting initiative.