Amgad Zeitoun

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Designers of content distribution networks often need to determine how changes to infrastructure deployment and configuration affect service response times when they deploy a new data center, change ISP peering, or change the mapping of clients to servers. Today, the designers use coarse, back-of-the-envelope calculations, or costly field deployments; they(More)
We call end-hosts behind Network Address Translator (NAT) gateways or firewalls guarded hosts, and otherwise open hosts. Due to mounting security threats and growing population of high-speed Internet users equipped with connection sharing, guarded hosts become increasingly common in today’s Internet. However, the presence of guarded hosts has a detrimental(More)
Path RTT plays a crucial role in several overlay network construction protocols, peer-to-peer applications, and proximity-based server redirection in such applications as multiplayer gaming and content distribution network. The RTT of a path is usually estimated as the minimum of a number of measurements. The number of probes reported used by these(More)
Future groupware systems will need to extend collaboration beyond the desktop. They will need to support computing devices with a wide range of capabilities, varying network connectivity, and increasing mobility of users. We have designed and implemented a component-based framework for building reconfigurable distributed applications that address the(More)
Several Internet mapping and topology discovery applications inspect multiple IP (Internet Protocol) addresses to discover Internet address regions that are alive, i.e., contain IP addresses that elicit replies to probes. Currently, the traditional approach in examining these IP addresses is completely random, uses exhaustive scan, or focuses on a common(More)
According to conventional wisdom, links connecting different Autonomous Systems (ASes) are the performance bottlenecks in the core of the Internet. This paper presents an empirical evaluation of delays across inter-AS links using hop-limited active probes. The measurements cover a diverse set of Internet paths starting from locations within three large(More)