Showing papers by "Tom Leighton published in 2001"
TL;DR: This paper analyzes the behavior of packet-switched communication networks in which packets arrive dynamically at the nodes and are routed in discrete time steps across the edges, and provides the first examples of a protocol that is stable for all networks, and a Protocol that is not stable forall networks.
Abstract: In this paper, we analyze the behavior of packet-switched communication networks in which packets arrive dynamically at the nodes and are routed in discrete time steps across the edges. We focus on a basic adversarial model of packet arrival and path determination for which the time-averaged arrival rate of packets requiring the use of any edge is limited to be less than 1. This model can reflect the behavior of connection-oriented networks with transient connections (such as ATM networks) as well as connectionless networks (such as the Internet).We concentrate on greedy (also known as work-conserving) contention-resolution protocols. A crucial issue that arises in such a setting is that of stability—will the number of packets in the system remain bounded, as the system runs for an arbitrarily long period of time? We study the universal stability of network (i.e., stability under all greedy protocols) and universal stability of protocols (i.e., stability in all networks). Once the stability of a system is granted, we focus on the two main parameters that characterize its performance: maximum queue size required and maximum end-to-end delay experienced by any packet.Among other things, we show:(i) There exist simple greedy protocols that are stable for all networks.(ii) There exist other commonly used protocols (such as FIFO) and networks (such as arrays and hypercubes) that are not stable.(iii) The n-node ring is stable for all greedy routing protocols (with maximum queue-size and packet delay that is linear in n).(iv) There exists a simple distributed randomized greedy protocol that is stable for all networks and requires only polynomial queue size and polynomial delay.Our results resolve several questions posed by Borodin et al., and provide the first examples of (i) a protocol that is stable for all networks, and (ii) a protocol that is not stable for all networks.
208 citations
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TL;DR: Various algorithms for solving the problem of learning as much as possible about the elements of X by asking binary questions are described, and upper and lower bounds on the efficiency of such algorithms are established.
31 citations
01 May 2001
TL;DR: An overview of how content is distributed on the internet is given, with an emphasis on the approach being used by Akamai, as well as some of the technical challenges involved in operating a network of thousands of content servers across multiple geographies.
Abstract: In this talk, we will give an overview of how content is distributed on the internet, with an emphasis on the approach being used by Akamai. We will describe some of the technical challenges involved in operating a network of thousands of content servers across multiple geographies on behalf of thousands of customers. The talk will be introductory in nature and should be accessible to a broad audience.
13 citations
TL;DR: It is shown that the isomorphism of two Cartesian powers Gr and Hr implies the isomorphicism of G and H, while Gr ⊆ Hr does not imply G ⊅ H, even for the special cases when G andH are connected or have the same number of nodes.
6 citations
08 Aug 2001
TL;DR: An overview of how content is distributed on the internet is given, with an emphasis on the approach being used by Akamai, as well as some of the technical challenges involved in operating a network of thousands of content servers across multiple geographies.
Abstract: In this talk, we will give an overview of how content is distributed on the internet, with an emphasis on the approach being used by Akamai. We will describe some of the technical challenges involved in operating a network of thousands of content servers across multiple geographies on behalf of thousands of customers. The talk will be introductory in nature and should be accessible to a broad audience.
1 citations
TL;DR: A new compression technique is introduced that uses efficient multicasting to significantly reduce the amount of information communicated during parallel and distributed computation, resulting in significantly faster algorithms for Fast Fourier Transforms and sorting on shared memory parallel models with limited bandwidth.
1 citations