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.

Secure Communication in Minimal Connectivity Models

Abstract: Problems of secure communication and computation have been studied extensively in network models. In this work we ask what is possible in the information-theoretic setting when the adversary is very strong (Byzantine) and the network connectivity is very low (minimum needed for crash-tolerance). We concentrate on a new model called ``multicast lines,'' and show a sizable gap between the connectivity required for perfect security and for almost perfect security. Our results also have implications to the commonly studied simple channel model and to general secure multiparty computation.

A measurement study on the impact of routing events on end-to-end internet path performance

Abstract: Extensive measurement studies have shown that end-to-end Internet path performance degradation is correlated with routing dynamics. However, the root cause of the correlation between routing dynamics and such performance degradation is poorly understood. In particular, how do routing changes result in degraded end-to-end path performance in the first place? How do factors such as topological properties, routing policies, and iBGP configurations affect the extent to which such routing events can cause performance degradation? Answers to these questions are critical for improving network performance.In this paper, we conduct extensive measurement that involves both controlled routing updates through two tier-1 ISPs and active probes of a diverse set of end-to-end paths on the Internet. We find that routing changes contribute to end-to-end packet loss significantly. Specifically, we study failover events in which a link failure leads to a routing change and recovery events in which a link repair causes a routing change. In both cases, it is possible to experience data plane performance degradation in terms of increased long loss burst as well as forwarding loops. Furthermore, we find that common routing policies and iBGP configurations of ISPs can directly affect the end-to-end path performance during routing changes. Our work provides new insights into potential measures that network operators can undertake to enhance network performance.

An Improved Feed-Forward Carrier Recovery Algorithm for Coherent Receivers With $M$ -QAM Modulation Format

Abstract: An improved feed-forward carrier phase recovery method is proposed for coherent receivers using M-ary quadrature amplitude modulation-based modulation formats. It is shown that by introducing multiple cascaded feed-forward carrier recovery stages, the required compute power can be significantly reduced compared to the prior art using the single-stage-based blind phase search method.

An adaptive version of the boost by majority algorithm

Abstract: We propose a new boosting algorithm. This boosting algorithm is an adaptive version of the boost by majority algorithm and combines bounded goals of the boost by majority algorithm with the adaptivity of AdaBoost.

Using static analysis for Ajax intrusion detection

Abstract: We present a static control-flow analysis for JavaScript programs running in a web browser. Our analysis tackles numerous challenges posed by modern web applications including asynchronous communication, frameworks, and dynamic code generation. We use our analysis to extract a model of expected client behavior as seen from the server, and build an intrusion-prevention proxy for the server: the proxy intercepts client requests and disables those that do not meet the expected behavior. We insert random asynchronous requests to foil mimicry attacks. Finally, we evaluate our technique against several real applications and show that it protects against an attack in a widely-used web application.