AT&T Labs

About: AT&T Labs is a based out in . It is known for research contribution in the topics: Network packet & The Internet. The organization has 1879 authors who have published 5595 publications receiving 483151 citations.

Architecture reviews: practice and experience

Abstract: Architecture reviews have evolved over the past decade to become a critical part of our continuing efforts to improve the state of affairs. We use them to identify project problems before they become costly to fix and to provide timely information to upper management so that they can make better-informed decisions. It provides the foundation for reuse, using commercially available software, and getting to the marketplace fast. The reviews also help identify best practices to projects and socialize such practices across the organization, thereby improving the organization's quality and operations.

Strictly nonblocking directional-coupler-based switching networks under crosstalk constraint

Abstract: Directional-coupler (DC)-based switching systems can switch signals at the rate of several terabits per second. Such switches can also transmit signals with multiple wavelengths simultaneously. Despite these advantages, DCs suffer from an intrinsic crosstalk problem that must be overcome in building a robust switching system. In this paper, the principles of constructing strictly nonblocking DC-based photonic switching systems under various crosstalk constraints are explored. We demonstrate how crosstalk adds a new dimension to the theory of switching systems. We find the sufficient nonblocking condition for photonic networks under crosstalk constraints and demonstrate that some well-known nonblocking networks can tolerate a stricter crosstalk constraint while retaining their hardware complexity. The theory developed in the paper can guide us in making the design tradeoff between the level of crosstalk and the amount of hardware.

Characterizing unstructured overlay topologies in modern P2P file-sharing systems

Abstract: During recent years, peer-to-peer (P2P) file-sharing systems have evolved in many ways to accommodate growing numbers of participating peers In particular, new features have changed the properties of the unstructured overlay topology formed by these peers Despite their importance, little is known about the characteristics of these topologies and their dynamics in modern file-sharing applicationsThis paper presents a detailed characterization of P2P overlay topologies and their dynamics, focusing on the modern Gnutella network Using our fast and accurate P2P crawler, we capture a complete snapshot of the Gnutella network with more than one million peers in just a few minutes Leveraging more than 18,000 recent overlay snapshots, we characterize the graph-related properties of individual overlay snapshots and overlay dynamics across hundreds of back-to-back snapshots We show how inaccuracy in snapshots can lead to erroneous conclusions--such as a power-law degree distribution Our results reveal that while the Gnutella network has dramatically grown and changed in many ways, it still exhibits the clustering and short path lengths of a small world network Furthermore, its overlay topology is highly resilient to random peer departure and even systematic attacks More interestingly, overlay dynamics lead to an "onion-like" biased connectivity among peers where each peer is more likely connected to peers with higher uptime Therefore, long-lived peers form a stable core that ensures reachability among peers despite overlay dynamics

For sale : your data: by : you

Abstract: Monetizing personal information is a key economic driver of online industry. End-users are becoming more concerned about their privacy, as evidenced by increased media attention. This paper proposes a mechanism called 'transactional' privacy that can be applied to personal information of users. Users decide what personal information about themselves is released and put on sale while receiving compensation for it. Aggregators purchase access to exploit this information when serving ads to a user. Truthfulness and efficiency, attained through an unlimited supply auction, ensure that the interests of all parties in this transaction are aligned. We demonstrate the effectiveness of transactional privacy for web-browsing using a large mobile trace from a major European capital. We integrate transactional privacy in a privacy-preserving system that curbs leakage of information. These mechanisms combine to form a market of personal information that can be managed by a trusted third party.

Network architecture for joint failure recovery and traffic engineering

Abstract: Today's networks typically handle traffic engineering (eg, tuning the routing-protocol parameters to optimize the flow of traffic) and failure recovery (eg, pre-installed backup paths) independently In this paper, we propose a unified way to balance load efficiently under a wide range of failure scenarios Our architecture supports flexible splitting of traffic over multiple precomputed paths, with efficient path-level failure detection and automatic load balancing over the remaining paths We propose two candidate solutions that differ in how the routers rebalance the load after a failure, leading to a trade-off between router complexity and load-balancing performance We present and solve the optimization problems that compute the configuration state for each router Our experiments with traffic measurements and topology data (including shared risks in the underlying transport network) from a large ISP identify a "sweet spot" that achieves near-optimal load balancing under a variety of failure scenarios, with a relatively small amount of state in the routers We believe that our solution for joint traffic engineering and failure recovery will appeal to Internet Service Providers as well as the operators of data-center networks