Beichuan Zhang

Adaptive forwarding in named data networking

Cheng Yi, Alexander Afanasyev, Lan Wang, Beichuan Zhang, Lixia Zhang
Appears in: 
CCR July 2012

In Named Data Networking (NDN) architecture, packets carry data names rather than source or destination addresses. This change of paradigm leads to a new data plane: data consumers send out Interest packets, routers forward them and maintain the state of pending Interests, which is used to guide Data packets back to the consumers. NDN routers' forwarding process is able to detect network problems by observing the two-way traffic of Interest and Data packets, and explore multiple alternative paths without loops.

Longitudinal Study of BGP Monitor Session Failures

Pei-chun Cheng, Xin Zhao, Beichuan Zhang, and Lixia Zhang
Appears in: 
CCR April 2010

BGP routing data collected by RouteViews and RIPE RIS have become an essential asset to both the network research and operation communities. However, it has long been speculated that the BGP monitoring sessions between operational routers and the data collectors fail from time to time. Such session failures lead to missing update messages as well as duplicate updates during session re-establishment, making analysis results derived from such data inaccurate.

Public Review By: 
Jitendra Padhye

Many researchers use BGP routing data collected by RouteView and RIPE servers as a starting point for their research. The data is affected by failure of BGP sessions between the operational routers and the data collectors, and hence must be sanitized before being used. This sanitization is often done in an ad-hoc manner by individual researchers to suit their needs.
To remedy this situation, the authors have systematically catalogued the session failures in the RouteView and RIPE data gathered over past eight years. The primary contribution of the paper is the database of these failures, which the authors have made available to the public. Furthermore, the authors plan to keep the failure database updated as new data comes in. This database will be a valuable resource to the researchers working in this area.
The authors also draw some basic conclusion from the failure data they gather. They point out that BGP session resets are quire frequent, although the downtime is often less than 10 minutes. Based on correlation between session failures, they conclude that often it is the collector that is at fault. Unfortunately, they are unable to shed any light on why the collectors fail. Some information in this regard may have been useful to improve to the collector’s performance.
The paper makes one wonder whether the flaws in these data sets may have influenced the conclusions of (many!) research studies based on them. The authors (or others) may want to consider it as part of their future work.

Observing the Evolution of Internet AS Topology

Ricardo V. Oliveira, Beichuan Zhang, and Lixia Zhang
Appears in: 
CCR October 2007

Characterizing the evolution of Internet topology is important to our understanding of the Internet architecture and its interplay with technical, economic and social forces. A major challenge in obtaining empirical data on topology evolution is to identify real topology changes from the observed topology changes, since the latter can be due to either topology changes or transient routing dynamics. In this paper, we formulate the topology liveness problem and propose a solution based on the analysis of BGP data.

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