L. Kleinrock

• University of California, Los Angeles

In this paper we examine the general problem of determining when to update information that can go out-of-date. Not updating frequently enough results in poor decision making based on stale information. Updating too often results in excessive update costs. We study the tradeoff between having stale information and the cost of updating that informat...

Reputation is a major component of trustworthy systems. However, the subjective nature of reputation, makes it tricky to base a system’s security on it. In this work, we describe how to leverage reputation to establish a highly scalable and efficient blockchain. Our treatment puts emphasis on reputation fairness as a key feature of reputation-based...

Recently there has been considerable interest in a key paper [1] describing a new approach to congestion control in Internet traffic which has resulted in significant network performance improvement. The approach is based on a 1978 paper [2] and a companion 1979 paper [3] which identified a system operating point that was optimal in that it maximiz...

Due to a poor understanding of the interactions among transmitters, wireless CSMA/CA networks have been commonly stigmatized as unpredictable in nature. Even quite elementary questions regarding the throughput limitations of these networks cannot be answered in general. In this paper we investigate the behavior of wireless networks using carrier se...

A number of interesting problems that I have addressed over the years which yielded surprisingly simple results will be presented. Many of these had intuitively pleasing interpretations or especially simple proofs and/or insights.

The great French writer, historian and philosopher Voltaire once asked, "Is there anyone so wise as to learn by the experience of others?" In celebration of the 20th MobiCom conference, join us for a thought provoking discussion between pioneers of our field on the lessons they have learned over their illustrious career paths that accelerated the p...

It was about 40 years ago that the ARPANET had surpassed 40 nodes and was rapidly growing at the rate of one node per month. The first government and commercial P/S networks were emerging. Designing an efficient topology and flow assignment strategy that could meet the requirements at lowest costs was essential in order to outperform the competitio...

Due to a poor understanding of the interactions among transmitters, wireless multihop networks have commonly been stigmatized as unpredictable in nature. Even elementary questions regarding the throughput limitations of these networks cannot be answered in general. In this paper we investigate the behavior of wireless multihop networks using carrie...

Abstract—We present a new routing paradigm that generalizes opportunistic routing for the multi-gateway case. In plasma anypath routing, each packet is delivered over the best available path to one of the gateways. The choice of the path and gateway for each packet is not made beforehand by the source node, but rather on-the-fly by the mesh routers...

Edge network operators have limited tools to control activities on their networks. This paper examines network dissuasion, a new approach to edge network control, based on controlling the fundamental parameters of the network, such as loss rate, delay, and jitter, with the intention of making particular uses of a network intolerable, while providin...

In this paper we present a new routing paradigm for wireless multihop networks. In plasma routing, each packet is delivered over the best available path to one of the gateways. The choice of the path and gateway for each packet is not made beforehand by the source node, but rather on-the-fly by the mesh routers as the packet traverses the network....

The first DARPA experiment with wireless mobile Internet – the Packet Radio Network or PRNET – was completely independent of the infrastructure. This model was consistent with DARPA military goals as the PRNET was designed to support tactical operations far away from any wired infrastructure. Beside autonomy, the main challenge was mobility and rad...

In this paper we present a new routing paradigm that generalizes opportunistic routing for wireless multihop networks. In multirate anypath routing, each node uses both a set of next hops and a selected transmission rate to reach a destination. Using this rate, a packet is broadcast to the nodes in the set and one of them forwards the packet on to...

The Transmission Control Protocol (TCP) carries most Internet traffic, so performance of the Internet depends to a great extent on how well TCP works. Performance characteristics of a particular version of TCP are defined by the congestion control algorithm it employs. This paper presents a survey of various congestion control proposals that preser...

It is impossible to place the origins of the Internet in a single moment of time. One could argue that its roots lie in the earliest communications technologies of centuries and millennia past, or the beginnings of mathematics and logic, or even with the emergence of language itself. For each component of the massive infrastructure we call the Inte...

The Internet has revolutionized the computer and communications world like nothing before. The invention of the telegraph, telephone, radio, and computer set the stage for this unprecedented integration of capabilities. The Internet is at once a world-wide broadcasting capability, a mechanism for information dissemination, and a medium for collabor...

In this paper, we present a new routing paradigm that generalizes opportunistic routing in wireless mesh networks. In multirate anypath routing, each node uses both a set of next hops and a selected transmission rate to reach a destination. Using this rate, a packet is broadcast to the nodes in the set and one of them forwards the packet on to the...

Ensuring spontaneous ad hoc interoperation in decentralized ubiquitous computing environments is challenging, because of heterogeneous resources and divergent policies. Centralized cross-domain service access agreements can be made with a priori knowledge of the interacting entities' policies, but privacy concerns make this approach impractical. En...

In this letter we mainly discuss the derivation of the multiple input queueing (MIQ) and virtual output queueing (VOQ) techniques applied in packet switching.

This article relates the history of wireless communications to the history of the Internet. The early work on packet switching is traced,and then a brief description of the critical events in the growth of the Internet is provided. Then, a vision of where the Internet is heading is presented, with a locus on where user participation, flexible appli...

The great success of P2P systems for the purpose of file-sharing set the path to the next killer application on the Internet, P2P video streaming. Although it solves scalability issues, P2P technology experiences problems of a long start time and churn-induced instability that can greatly affect the user experience. Moreover, technical and business...

This paper derives the optimal search time and the optimal search cost that can be achieved in unstructured peer-to-peer networks when the demand pattern exhibits clustering (i.e. file popularities vary across the set of nodes in the network). Clustering in file popularity patterns is evident from measurements on deployed peer-to-peer file sharing...

Peer-to-peer live video streaming over the Internet has been measured to support over 100,000 concurrent users. While the approach is very attractive, established providers need to understand the performance of such a system before deploying such a system as a frequent loss in quality would jeopardize their reputation. This paper provides an analyt...

This paper derives the optimal search time and the optimal search cost that can be achieved in unstructured peer-to-peer networks when the demand pattern exhibits clustering (i.e. file popularities vary from region to region in the network). Previous work in this area had assumed a uniform distribution of file replicas throughout the network with a...

The increasing ease of self-expression and web-publishing has resulted in an explosion in the amount of content being generated in the current Internet. Besides traditional sources such as news portals, regular users are documenting their lives and thoughts and other people are subscribing, downloading and viewing this content. A lot of content the...

We recently showed for peer-to-peer networks, that having the number of replicas of each object proportional to the request rate for these objects has many per-node advantages. In this paper we complement those results to show that this distribution has network-wide advantages as well. Given these benefits of proportional replication, the next issu...

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AdTorrent is an integrated system for search, rank-ing and content delivery in car networks. AdTorrent builds on the notion of Digital Billboards, a scalable "push" model architecture for ad content delivery. We present a detailed analysis of the performance impact of key design parameters such as scope of the query flooding on the query hit ratio....

Origins of the Internet The Initial Internetting Concepts Proving the Ideas Transition to Widespread Infrastructure The Role of Documentation Formation of the Broad Community Commercialization of the Technology History of the Future Conclusion Keywords: internet (the history); packet-switching technology

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering, 1963. MICROFICHE COPY AVAILABLE IN ENGINEERING. Vita. Includes bibliographical references (leaves 267-269). by Leonard Kleinrock. Ph.D.

This paper investigates the effect of the number of file replicas on search performance in unstructured peer-to-peer networks. We observe that for a search network with a random graph topology where file replicas are uniformly distributed, the hop distance to a replica of a file is logarithmic in the number of replicas. Using this observation we sh...

This paper investigates the effect of the number of file replicas on search performance in unstructured peer-to-peer networks. We observe that for a search network with a random graph topology where file replicas are uniformly distributed, the hop distance to a replica of a file is logarithmic in the number of replicas. Using this observation we sh...

Each peer in a peer-to-peer network, by definition, is both a consumer and a provider of the service. As a consumer, a peer wants to obtain its objects of interest as quickly as possible. However, as a service provider, the peer wants to serve no more than an equitable portion of the total workload. Our first observation in this paper is that if on...

Search time as a function of the number of replicas of a queried object provides a key component to understanding system behavior in peer-to-peer networks. The analytical work in this area so far has assumed a uniform distribution of file replicas throughout the network with an implicit or explicit assumption of uniform file popularity distribution...

Dr. Leonard Kleinrock created the basic principles of packetswitching, the technology underpinning the Internet, while agraduate student at MIT. This was a decade before the birth of theInternet which occurred when his host computer at UCLA became thefirst node of the ARPANET in September 1969. He wrote the firstpaper and published the first book o...

Imagine that we had carefully established the rules of engagement for the Internet in its earliest days around the time of its birth in 1969. What would those rules have contained? What, indeed, were the underlying principles and policies that we actually documented, said, understood, implied, and instilled back then? What, if any, additional eleme...

The rapid growth and increasing pervasiveness of wireless networks raises serious security concerns. Client devices will migrate between numerous diverse wireless environments, bringing with them software vulnerabilities and possibly malicious code. Techniques are needed to protect wireless client devices and the next generation wireless infrastruc...

The rapid growth and increasing pervasiveness of wireless networks raises serious security concerns. Client devices will migrate between numerous diverse wireless environments, bringing with them software vulnerabilities and possibly malicious code. Techniques are needed to protect wireless client devices and the next generation wireless infrastruc...

This paper takes us on a short journey from traditional desktop computing to the three emerging dimensions of: Nomadicity (the system support needed to provide a rich set of computing and communication capabilities and services to nomads as they move from place to place in a way that is transparent, integrated, convenient and adaptive); embeddednes...

Sensor networks are distributed networks made up of small sensing devices equipped with processors, memory, and short-range wireless communication. They differ from the conventional computer networks in that they have severe energy constraints, redundant low-rate data, and a plethora of information flows. Many aspects of sensor networks, such as ro...

if we have a !arge population of users sharing a common broadcast channel using the Slotted Aloha access scheme.

this paper) that should be sending information at any given time. In this paper we present an amalgamation of QoS feedback and sensor networks. We use the idea of allowing the base station to communicate QoS information to each of the sensors using a broadcast channel and we use the mathematical paradigm of the Gur Game to dynamically adjust to the...

Future ubiquitous computing environments will require devices to be automatically and safely configured together to perform important tasks for the users they support. Security concerns based on known vulnerabilities of the Internet make it clear that any widely deployed new computing infrastructure must be designed with substantially more security...

ln two companion papers a method for multiplexing a population of terminals communicating with a central station over a packet-switched radio channel was introduced; this method is known as Carrier Sense Multiple Access (CSMA). CSMA, as with ALOHA multiaccess broadcast channels, has the unfortunate property that the throughput falls to zero as the...

We study new access schemes for a population of geographically disiributed data users who communicate with each other and/or with a central station over a multiple-acces broadcasi ground radio packet-switching channel. We introduce and analyze alternating priorities (AP), round robin (RR), and random order (RO) as new conflict-free methods for mult...

A new carrier sense multiple acces (CSMA) algorithm, called virtual time CSMA, is described and analyzed. This algorithm uses a novel approach to granting access to the shared broadcast channel based on variable-rate clocks. Unlike other CSMA algorithms, the operation of virtual time CSMA reduces to the ideal case in the zero propagation time limit...

This paper deals with the specification, analysis and evaluation of some hierarchical routing procedures which are effoctive for large stoa-and-forward packet-witched computsr networks. The proniures studied ate an extension of present techniques and rely on a hkratchical clustering of the network nodes. In particular, optimal clustering structures...

1. ORIGINS It all began with a comic book! At the age of 6, I was reading a Superman comic at my apartment in Manhattan when, in the centerfold, I found plans for building a crys- tal radio. To do so, I needed my father's used razor blade, a piece of pencil lead, an empty toilet paper roll, and some wire, all of which I had no trouble obtaining. In...

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Internet's ultimate utility depends on ability and willingness to make the network at least as pervasive, convenient and invisible as electricity is today. Internet is ubiquitous, always available, and always on, but has so far missed that any device could be plugged in at any location and it would be as invisible as electricity. Basically, the mis...

this article, see http://www.isoc.org/internet-history. COMMUNICATIONS OF THE ACM February 1997/Vol. 40, No. 2 103 computers through which everyone could quickly access data and programs from any site. In spirit, the concept was much like the Internet today. While at DARPA, 3 he convinced the people who would be his successors there---Ivan Sutherla...

We present two new models and their exact analysis for the problem of two processors running the Time Warp distributed simulation protocol. Our first model addresses the queueing of messages at each processor while the second model adds costs for rollback and state saving. Both models provide insight into the operation of freerunning systems synchr...

Modern networks are extremely complex, varying both statically and dynamically. This complexity and dynamism are greatly increased when the network contains mobile elements. A number of researchers have proposed solutions to these problems based on dynamic adaptation to changing network conditions and application requirements. This paper summarizes...

The goal of the SESAME project has been to create a set of tools to study the performance of operating systems. This project developed a method for observing component behavior inside the operating system kernel in fully running computers, a method for modeling the effects of changes, and a method for sharing the results among researchers. These ha...

In this article we identify some of the key problems one encounters when thinking about multi-access systems. We begin with a general discussion of nomadic computing and move on to issues of multi-access in a distributed environment. We then specialize to the case of wireless systems, and identify some of the key considerations and algorithms which...

This paper discusses techniques for transmitting smoothed video more efficiently over a wireless network. The fluctuation of wireless channel conditions can add a significant amount of delay to video packets and cause them to miss their play-out time. If a video is smoothed, it is possible to selectively deliver packets delayed at the base-station...

Currently, most users think of their computers as associated with their desktop appliances or with a server located in a dungeon in some mysterious basement. However, many of those same users can be considered nomads, in that they carry computers and communication devices with them in their travels between office, home, airport, hotel, automobile,...

A Moore's law “technology generation” is 18 months; an “Internet generation” is comparably short. Thus, over the next decade (2000-2010), we will experience perhaps six generations of technology change; a substantial amount considering its implied exponential character. The cumulative effects of such changes in information technology will be compar...

We are in the midst of some truly revolutionary changes in the field of computer-communications, and these offer opportunities and challenges to the research community. One of these changes has to do with nomadic computing and communications. Nomadicity refers to the system support needed to provide a rich set of capabilities and services to the no...

This paper introduces and studies the performance of an N Theta N space-division, single-stage ATM switch with dual input-queueing. Each input port has two separate FIFO queues, an "odd" and an "even" queue. An incoming cell is stored at the input at either of two FIFOs according its output port destination (output ports are also labeled as "odd" o...

In this paper we apply the notion of Power, as has been defined by one of the authors for a general communications system, to ATM switching systems. In general, the Power of a system synthesizes basic performance metrics such as the system's throughput, mean delay and packet loss. This integrated measure can be used to characterize the performance...

The Internet has revolutionized the computer and communications world like nothing before. The invention of the telegraph, telephone, radio, and computer set the stage for this unprecedented integration of capabilities. The Internet is at once a world-wide broadcasting capability, a mechanism for information dissemination, and a medium for collabor...

The pervasive nature of computing and communications is bringing about a paradigm shift in the way these technologies are being used. The shift is in the direction of nomadic computing and communications. Nomadicity refers to the system support needed to provide a rich set of computing and communication capabilities and services to the nomad as he...

Prefetching is one of the most popular techniques for dealing with the slow access speed of the World Wide Web. To provide a mobile user with effective real time online prefetching requires that the prefetch decision is able to adapt to different network systems. This article describes an adaptive network prefetch scheme which accomplishes this tas...

Summary form only given, as follows. Most of us are nomads in that we travel from place to place with a wild array of laptops, PDA's, cellular telephones, pagers, etc. We desire to have the same computing environment, services and system support in those locations as we have in our corporate offices. Indeed we desire “anywhere, anytime” connectivit...

In this paper, we present an adaptive prefetch scheme for network use, in which we download files that will very likely be requested in the near future, based on the user access history and the network conditions. Our prefetch scheme consists of two parts: a prediction module and a threshold module. In the prediction module, we estimate the probabi...

This paper introduces and studies the performance of an N x N space-division, single-stage ATM switch with dual input-queueing, Each input port has two separate FIFO queues, an "odd" and an "even" queue. An incoming cell is stored at the input at either of two FIFOs according its output port destination (output ports are also labeled as "odd" or "e...

Multistage Interconnection Networks (MINs) are very popular in ATM switching since they can achieve high-performance switching and are easy to implement and expand due to their modular design. In this paper we present and describe in detail a high-performance buffered-banyan switch which encompasses multiple input-queueing as its buffering strategy...

We apply the notion of power, as has been defined by one of the authors for a general communications system, to ATM switching systems. In general, the power of a system synthesizes basic performance metrics such as the system's throughput, mean delay and packet loss. This integrated measure can be used to characterize the performance of a system (e...

Multiplane switches present a special interest in the field of ATM switching as they are high-performance scaleable architectures. Not only are they efficient in terms of performance but they also offer a high-degree of reliability, an issue which is very critical to ATM networks. We present a number of different switching architectures based on mu...

Video smoothing is a promising technique for reducing the bandwidth variability of video in order to improve network efficiency. This paper presents a general optimal video smoothing algorithm based on the concept of dynamic programming. The algorithm generates the optimum transmission schedule for different requirements by setting the constraints...

In a previous paper [1], we proposed and analyzed a timeout scheme to alleviate network congestion and thus improve the throughput for a wormhole routing network in local area network (LAN) environments. This timeout scheme was proved to be effective, but the optimal timeout value varies with packet size, propagation delay, and other network parame...

In this paper, we study prefetch techniques in the WWW, in which we predict which files will be needed in the near future and download some of them before they are requested by the user. Our prefetch scheme includes two algorithms: the prediction algorithm and the threshold algorithm. The prediction algorithm estimates the probability with which ea...

In this paper, we study prefetch techniques in the WWW, in which we predict which files will be needed in the near future and download some of them before they are requested by the user. Our prefetch scheme includes two algorithms: the prediction algorithm and the threshold algorithm. The prediction algorithm estimates the probability with which ea...

Multistage interconnection networks (MINs) are very popular in ATM switching since they can achieve high-performance switching and are easy to implement and expand due to their modular design. In this paper we present and describe in detail a high-performance buffered-Banyan switch which encompasses multiple input-queueing as its buffering strategy...

The Internet began as a modest research experiment to link three early packet networks in an open-architecture framework. In due course, many other networks were connected, thus spawning a revolution in networking that continues to this day The early technology considerations inevitably led to social, administrative and commercial issues, and ultim...

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Nomadic computing is a phenomenon in computing and communications that is spreading rapidly. At this stage of its technology, the key problems and the basic understanding of its underlying principles are only beginning to be identified. Analysis and design tools are needed to assist in its development. In this paper, we discuss the nature of the to...

Current wireless network systems (e.g. metropolitan cellular) are constrained by fixed bandwidth allocations and support only a narrow range of services (voice and low bit-rate data). To overcome these constraints and advance the state of the art in wireless multimedia communications, we are developing variable-rate video and speech compression alg...

Current quality of service schemes require switching nodes to identify and manipulate packets within large switch buffers. These methods are effective for networks with switching nodes that contain sufficient resources, such as in ATM networks. However, in wormhole routing networks like Myrinet, the emphasis on providing low latency and high link s...

This paper introduces and studies the performance of an N×N space-division, single-stage ATM switch with dual input-queueing. Each input port has two separate FIFO queues, an “odd” and an “even” queue. An incoming cell is stored at the input at either of two FIFOs according its output port destination (output ports are also labeled as “odd” or “eve...

Current fiber optic networks effectively provide local connectivity among end user computing devices, and can serve as backbone fabric between LAN subnets across campus and metropolitan areas. However, combining both stream service (in which ATM excels) and low latency datagram service (in which cluster networks like Myrinet and POLO excel) has bee...

A simple game provides a framework within which agents can spontaneously self-organize. In this paper, we present this game, and develop basic theory underlying a robust method for distributed coordination based on this game. This method makes use of finite state automata-one associated with each agent-which guide the agents. We give a new, general...

The authors consider a networking environment in which the users are mobile, the topology changes, code division multiple access (CDMA) provides multiple wireless channels, the bandwidth of a given link is unpredictable and possibly very low, the error rates are extremely high and variable, major interference occurs when multiple transmissions take...

The Supercomputer Supernet (SSN) is a novel, high-performance, scalable optical interconnection network for supercomputers and workstation clusters based on asynchronous wormhole routing crossbar switches. The WDM fiber optics extends the geographic coverage range from interdepartmental to campus and even to metropolitan areas with direct or multi-...

Current fiber optic networks effectively provide local connectivity among end user computing devices, and can serve as backbone fabric between LAN subnets across campus and metropolitan areas. However, combining both stream service (in which ATM excels) and low latency datagram service (in which cluster networks like Myrinet and POLO excel) has bee...

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A hierarchical simulator has been designed for multimedia communication protocols in a wireless mobile environment. The hierarchical approach integrates performance evaluation of protocols with their implementation. The approach supports scalability studies of the protocols in an efficient manner using coarse grain models that abstract implementati...

Nomadic computing and communications is upon us. We are all nomads, but we lack the systems support to assist us in our various forms of mobility. In this paper, we discuss the vision of nomadicity, its technical challenges, and approaches to the resolution of these challenges. One of the key characteristics of this paradigm shift in the way we dea...

Computing and communications is bringing about a paradigm shift in the way these technologies are being used. The shift is in the direction of nomadic computing and communications. Nomadicity refers to the system support needed to provide a rich set of computing and communication capabilities and services to the nomad as he or she moves from place...