Roch Guerin

Bio: Roch Guerin is an academic researcher from Washington University in St. Louis. The author has contributed to research in topics: Network packet & Routing protocol. The author has an hindex of 55, co-authored 214 publications receiving 15182 citations. Previous affiliations of Roch Guerin include University of California, Irvine & University of Massachusetts Amherst.

Equivalent capacity and its application to bandwidth allocation in high-speed networks

Abstract: The authors propose a computationally simple approximate expression for the equivalent capacity or bandwidth requirement of both individual and multiplexed connections, based on their statistical characteristics and the desired grade-of-service (GOS). The purpose of such an expression is to provide a unified metric to represent the effective bandwidth used by connections and the corresponding effective load of network links. These link metrics can then be used for efficient bandwidth management, routing, and call control procedures aimed at optimizing network usage. While the methodology proposed can provide an exact approach to the computation of the equivalent capacity, the associated complexity makes it infeasible for real-time network traffic control applications. Hence, an approximation is required. The validity of the approximation developed is verified by comparison to both exact computations and simulation results. >

Specification of Guaranteed Quality of Service

Abstract: This memo describes the network element behavior required to deliver a guaranteed service (guaranteed delay and bandwidth) in the Internet Guaranteed service provides firm (mathematically provable) bounds on end-to-end datagram queueing delays This service makes it possible to provide a service that guarantees both delay and bandwidth This specification follows the service specification template described in [1]

QoS Routing Mechanisms and OSPF Extensions

Abstract: This memo describes extensions to the OSPF [Moy98] protocol to support QoS routes. The focus of this document is on the algorithms used to compute QoS routes and on the necessary modifications to OSPF to support this function, e.g., the information needed, its format, how it is distributed, and how it is used by the QoS path selection process. Aspects related to how QoS routes are established and managed are also briefly discussed. The goal of this document is to identify a framework and possible approaches to allow deployment of QoS routing capabilities with the minimum possible impact to the existing routing infrastructure.

A Framework for Policy-based Admission Control

Abstract: This document is concerned with specifying a framework for providing policy-based control over admission control decisions. This memo provides information for the Internet community.

Channel occupancy time distribution in a cellular radio system

Abstract: The distribution of the channel occupancy time in a cellular radio system is studied, namely, the distribution of the time spent by customers on one frequency channel within a given cell. Two approaches are used. The first one relies on a computer simulation allowing a general model for mobiles behavior. The second is analytical, and assume a simplified system where mobiles keep constant directions. The results of both methods are compared with a fitted exponential distribution, and excellent agreements are found for most practical situations. In addition, a simple expression giving the average number of handoffs for a random customer is obtained. The results derived in this paper provide useful and simple tools to analyze cellular systems.

Handbook of Applied Cryptography

Abstract: From the Publisher: A valuable reference for the novice as well as for the expert who needs a wider scope of coverage within the area of cryptography, this book provides easy and rapid access of information and includes more than 200 algorithms and protocols; more than 200 tables and figures; more than 1,000 numbered definitions, facts, examples, notes, and remarks; and over 1,250 significant references, including brief comments on each paper.

Random graphs

Abstract: We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.

A generalized processor sharing approach to flow control in integrated services networks: the multiple node case

Abstract: Worst-case bounds on delay and backlog are derived for leaky bucket constrained sessions in arbitrary topology networks of generalized processor sharing (GPS) servers. The inherent flexibility of the service discipline is exploited to analyze broad classes of networks. When only a subset of the sessions are leaky bucket constrained, we give succinct per-session bounds that are independent of the behavior of the other sessions and also of the network topology. However, these bounds are only shown to hold for each session that is guaranteed a backlog clearing rate that exceeds the token arrival rate of its leaky bucket. A much broader class of networks, called consistent relative session treatment (CRST) networks is analyzed for the case in which all of the sessions are leaky bucket constrained. First, an algorithm is presented that characterizes the internal traffic in terms of average rate and burstiness, and it is shown that all CRST networks are stable. Next, a method is presented that yields bounds on session delay and backlog given this internal traffic characterization. The links of a route are treated collectively, yielding tighter bounds than those that result from adding the worst-case delays (backlogs) at each of the links in the route. The bounds on delay and backlog for each session are efficiently computed from a universal service curve, and it is shown that these bounds are achieved by "staggered" greedy regimes when an independent sessions relaxation holds. Propagation delay is also incorporated into the model. Finally, the analysis of arbitrary topology GPS networks is related to Packet GPS networks (PGPS). The PGPS scheme was first proposed by Demers, Shenker and Keshav (1991) under the name of weighted fair queueing. For small packet sizes, the behavior of the two schemes is seen to be virtually identical, and the effectiveness of PGPS in guaranteeing worst-case session delay is demonstrated under certain assignments. >

Keying Hash Functions for Message Authentication

Abstract: The use of cryptographic hash functions like MD5 or SHA-1 for message authentication has become a standard approach in many applications, particularly Internet security protocols. Though very easy to implement, these mechanisms are usually based on ad hoc techniques that lack a sound security analysis. We present new, simple, and practical constructions of message authentication schemes based on a cryptographic hash function. Our schemes, NMAC and HMAC, are proven to be secure as long as the underlying hash function has some reasonable cryptographic strengths. Moreover we show, in a quantitative way, that the schemes retain almost all the security of the underlying hash function. The performance of our schemes is essentially that of the underlying hash function. Moreover they use the hash function (or its compression function) as a black box, so that widely available library code or hardwair can be used to implement them in a simple way, and replaceability of the underlying hash function is easily supported.