Abstract: Linux offers a rich set of traffc control functions. This document gives an overview of the design of the respective kernel code, describes its structure, and il-lustrates the addition of new elements by describing a new queuing discipline.

Abstract: Current resource reservation architectures for multimedia networks do not scale well for a large number of flows. We propose a new architecture that automatically aggregates flows on each link in the network. Therefore, the network has no knowledge of individual flows. There is no explicit signalling protocol, and the protocol overhead mainly consists in the introduction of a packet type with three values (reserved, request or best-effort) which can be encoded on two bits.

Abstract: A number of recent proposals and proposed standards have addressed adding differential services to the Internet. Although their details and tentative implementations differ, most are recommending what essentially amounts to multiple levels of best-effort service. In this paper, we survey recent differential services and pricing proposals and introduce a pricing framework for a differentiated-services network that focuses on simplicity, flexibility, and ease of implementation. In particular, our model can be used in the current heterogeneous Internet without major restructuring. We focus on flat-rate, per-time and usage-based pricing, where users can change their service level on an ad-hoc basis. We also show that a sender-pays model with back-charging is simple to implement and can be effective even in compli-cated transactions, such as multicasting. Our approach is different from many previous proposals and consciously inte-grates differential services and pricing with implementation as the immediate goal. Finally, we outline future areas of research including ISP support for pricing, the dynamics of service quality and pricing in a differentiated Internet, and the latest trends and directions of QoS deployment and standardization..

Abstract: This document contains a tutorial on the recent work in the area of offering services in the Internet. We cover the principles and some of Differentiated Services. We also explain the relationship to RSVP of each of these architectures. Finally, we draw some conclusions about the relationship of these architectures to SURFnet.

Abstract: This informational draft presents performance problems associated with TCP flows running over the assured service. It proposes the use of TCP-friendly differentiated services building blocks, specifically TCP friendly traffic conditioners to alleviate these problems.

Abstract: This paper presents a system for billing users for their TCP traffic. This is achieved by postponing the establishment of connections while the user is contacted, verifying in a secure way that they are prepared to pay. By presenting the user with cost and price information, the system can be used for cost recovery and to encourage efficient use of network resources. The system requires no changes to existing protocols or applications and can be used to recover costs between cooperating sites. Statistics collected from a four day trace of traffic between the University of California, Berkeley and the rest of the Internet demonstrate that such a billing system is practical and introduces acceptable latency. An implementation based on the BayBridge prototype router is described. Our study also indicates that pricing schemes may be used to control network congestion either by rescheduling time-insensitive traffic to a less expensive time of the day, or by smoothing packet transfers to reduce traffic peaks.

Abstract: The Internet Demand Experiment or INDEX is a market and technology trial. Its objective is to determine how much users value different qualities of service for Interent access. Findings from the trial imply that today's system of flat-rate pricing by ISPs is very inefficient. Flat-rate pricing wastes resources, requires light users to subsidize heavy users, and hinders deployment of broadband access. INDEX is a prototype of an alternative ISP model that offers differentiated-quality service on demand, with prices that reflect resource cost. In this alternative ISP consumers pay less, suppliers increase profits, and the deployment of broadband access is facilitated.

Abstract: Valuable high-end communication services cannot be assigned in a cooperative fashion, they must be rather granted on grounds of economic admission policies. Usage-based pricing models for an integrated services Internet have been proposed, but on a theoretical level only. In this paper, a control protocol for charging and accounting resource reservations in the integrated services Internet is presented, highlighting implementation issues and performance aspects with such usage-based pricing models. The general design decisions as well as a first implementation are described. They are based on a simple version of the resource reservation protocol RSVP. The pricing models employed were (1) an auction-based pricing model (delta auction) and (2) an adaptive, load-sensitive, volume pricing model. The protocol can handle these pricing models concurrently, i.e., it supports local pricing decisions. Furthermore, sender and receiver of a connection can share the cost of a trans mission. Finally, the prototype implementation was used to obtain first results and measurements concerning the overhead in terms of network and computing resources. Processing overhead for large number of flows and dynamic pricing schemes was measured at less than 2.3% and protocol overhead is typically 0.75%. Keywords: Charging, Accounting, Internet Protocol, Economic Models, Usage-based Pricing, Resource Reservation, Service Class Model, Quality of Service (QoS).

Abstract: The Differentiated Services architecture allows a service provider to configure new services dynamically using a policy protocol. This benefit, however, may not be fully realized if the service provider can not charge for the services, or need a high effort to update its billing system to charge for the services. Thus, there is a real need for a flexible billing architecture to complement the flexibility offered by the differen-tiated service model. To meet this need, a policy-based billing architecture is proposed in this paper. This architecture allows a service provider to define policies for configuring various processes of a billing system based on the charging and pricing schemes used for individual services. It is demonstrated how the architecture supports flat-rate, duration-based and volume-based charging, and also both static and dynamic pricing. Definitions of policies for various charging and pricing schemes are discussed and the potential complexity of each of them is analyzed. Based on the complexity analysis we recommend the least complex charging schemes for four classes of differentiated services, which have been proposed for meeting different application requirements.

Abstract: This memo describes a proposed MIB for the Differentiated Services Architecture.

Abstract: Differentiated Services is an Internet Engineering Task Force (IETF) standards effort to create a simple scheme which provides a range of quality of service (QoS) levels. It is one of the few technologies to date that will enable networks to handle traffic in a specific manner to meet the service demands of particular applications. This book offers network architects, engineers, and managers of Internet and other packet networks critical insight into the continuing development of Differentiated Services. Differentiated Services for the Internet includes: Exploration of how Diffserv can be used to diversify Internet service offerings Detailed evaluation of the advantages and disadvantages of Differentiated Services (Diffserv) in comparison to traditional best effort network services Coverage of the IETF's Diffserv specification-the necessary basis for implementations of the technology Detailed coverage of interworking Diffserv with Integrated Services (Intserv) networks

Abstract: Expect is a tool for automating interactive applications. Expect was constructed using Tcl, a language library designed to be embedded into applications. This paper describes experiences with Expect and Tcl over a seven year period. These experiences may help other exten-sion designers as well as the Tcl developers or develop-ers of any other extension language see some of the challenges that a single extension had to deal with while evolving at the same time as Tcl. Tcl and Expect users may also use these 'war stories' to gain insight into why Expect works and looks the way it does today.

Abstract: The Differentiated Services architecture allows a service provider to configure new services dynamically using a policy protocol. This benefit, however, may not be fully realized if the service provider can not charge for the services, or need a high effort to update its billing system to charge for the services. Thus, there is a real need for a flexible billing architecture to complement the flexibility offered by the differen-tiated service model. To meet this need, a policy-based billing architecture is proposed in this paper. This architecture allows a service provider to define policies for configuring various processes of a billing system based on the charging and pricing schemes used for individual services. It is demonstrated how the architecture supports flat-rate, duration-based and volume-based charging, and also both static and dynamic pricing. Definitions of policies for various charging and pricing schemes are discussed and the potential complexity of each of them is analyzed. Based on the complexity analysis we recommend the least complex charging schemes for four classes of differentiated services, which have been proposed for meeting different application requirements.

Abstract: This work presents the development of a distributed application in the security management area for telecommunication networks. The application consists of a system that intends to avoid the use of cloned telephones. The main focus of this work is classifying the telephone users into seven classes according to their usage logs. Such logs contain three relevant characteristics for every call made by the user. From this classification, that makes use of pattern recognition techniques, it is possible to identify more easily if a call does not correspond to the patterns of a specific user, and thus identify whether the call was made by an impostor. As a consequence, the immediate identification of the fraud, instead of at the moment of receiving the monthly bill, will reduce loss for both users and carriers. The MatLab software was employed to implement the classification algorithms (K-means, P-nearest neighbour, and Gauss) while C++ and Java, with CORBA support, were employed to implement the distributed system (manager and agent) that makes use of a data base containing information about the user classification.

Abstract: There are repeating patterns in the histories of communication technologies, including ordinary mail, the telegraph, the telephone, and the Internet. In particular, the typical story for each service is that quality rises, prices decrease, and usage increases to produce increased total revenues. At the same time, prices become simpler. The historical analogies of this paper suggest that the Internet will evolve in a similar way, towards simplicity. The schemes that aim to provide differentiated service levels and sophisticated pricing schemes are unlikely to be widely adopted. Price and quality differentiation are valuable tools that can provide higher revenues and increase utilization efficiency of a network, and thus in general increase social welfare. Such measures, most noticeable in airline pricing, are spreading to many services and products, especially high-tech ones. However, it appears that as communication services become less expensive and are used more frequently, those arguments lose out to customers' desire for simplicity. Flat rates are the simplest form of pricing. Although they have generally been regarded as irrational, and economically and socially undesirable, they have serious advantages. Consumers like them, and are willing to pay extra for them. Further, flat rates are extremely effective in stimulating usage, which is of advantage in a rapidly growing service like the Internet.

Abstract: This tutorial should assist the reader in understanding and writing Jasmin scripts, which can be installed at an SNMP agent supporting the Script MIB and which can be executed by the Jasmin runtime engine.

Abstract: This paper discusses the security aspects of the IETF Script MIB which integrates the Management by Delegation Model into the Internet Management Framework. The paper shows how SNMPv3 security mechanisms have been utilized to protect the Script MIB from unauthorized access. This paper also describes the security aspects of a prototype implementation which uses the Java virtual machine as a runtime system for delegated management functions.

Abstract: Charging for traffic in the Internet is gaining importance, due to the introduction of different Quality of Service classes and the increasing access speeds of end-users. Current charging schemes are limited since they do not allow Internet Service Providers (ISPs) to charge customers of other ISPs for data that is transferred to these customers. This paper presents an architecture for reverse charging in the Internet, that does allow such payments to be made. Reverse charging enables new business scenarios for traffic flow in the Internet.

Abstract: Since the original days of SNMP back in early 1988, the requirements for managing IP-based networks like the Internet have changed considerably. An important change is that the total amount of management in-formation that needs to be transferred has increased greatly. Not only did the size of traditional MIB data grow, for example IP routing tables and TCP connection tables, but also new types of management information appeared, for instance accounting tables, which tend to be bulky. The widely deployed SNMP version 1 was not designed for transferring large amounts of data. The overall latency of such transfers can be quite high and the way in which the SNMP messages are encoded for transmission over the network is not particularly efficient. The new version 3 of the SNMP protocol, while improving on other issues like security and access control, does not improve the transfer of large amounts of MIB data sufficiently, even though it provides a get-bulk operation. In this article, we look into ways of making bulk trans-fers of MIB data between SNMP agents and managers more efficient. We consider a bulk transfer to be the transfer of several hundreds of kilobytes of MIB data in a single logical transaction. For bulk transfers, our objectives are: - to reduce the end-to-end latency (i.e., the total time to transfer a set of management data between an agent and a manager, including marshalling, un-marshalling and network transfer); - to reduce the network overhead (i.e., the ratio be-tween the amount of bytes transferred over the network and the actual management information); and - to improve the retrieval of SNMP MIB tables (by both reducing latency and network overhead for the particular case of table retrieval). These objectives share a common goal: to improve the scalability of network management in the IP world.

Abstract: This paper presents the results of a case study performed for SURFnet bv. to determine if the time is ripe to introduce ATM SVCs into the Dutch ATM research network. The current state of the art in ATM SVCs is that vendors have been shipping SVC capable equipment for some time now. SVCs seem attractive, in the sense that they can be created on demand and instantaneously by the user, and that they are guar-anteed to provide the QoS level that the user requested. In case of overload, however, ATM will no longer be able to accept new connections and users will experience denial of service. The question being addressed in this paper is whether such denial of service situations can be managed using current equipment and standardized solu-tions. Three strategies are being examined: is it possible to introduce different access policies for different users; is it possible to intervene in existing connections and is it possible to reduce network load by calling users to account? The outcome of the case study is that denial of service problems can not yet be managed properly. For this reason, and despite the availability of SVC capable ATM products, SURFnet decided to call off the introduction of ATM SVCs.

Abstract: The Asynchronous Transfer Mode (ATM) is a networking technology for the transport of different types of information, all in fixed sized, small units called cells, and allows this to be done with a predeter-mined, guaranteed Quality of Service. Currently the process of standardisation of many aspects of ATM is well on the way and with ATM starting to be deployed in production environments, the need for ade-quate management of ATM networks arises. Also in the area of management of ATM networks stand-ardisation efforts have already been made and those efforts are still continuing at this moment. In this thesis the current state of the art in ATM management is investigated, with a particular interest for the Simple Network Management Protocol (SNMP) as the management protocol for ATM management. In Chapter 2 some of the key concepts of ATM are introduced, and Chapter 3 discusses how SNMP can be used for ATM management. In the Chapters 4 through 6 the state of the art in SNMP based ATM management is described. There are separate chapters for two of the major organisations that are active in that area: the Internet Engineering Task Force and the ATM Forum. Also there is a chapter that describes what some of vendors of ATM equipment have done so far to enable SNMP based management of their products (like ATM switches). Chapter 7 presents the actual analysis of the material presented in the previous chapters on the state of the art in ATM management. This analysis includes a classification of management functions, and an inventory of required management information for each category. Then, based on the classification and inventory, the analysis is performed. In Chapter 8 some of the practical experiences with ATM management are described. Using a set of SNMP management tools (which are in the public domain) and two different available ATM switches some experiments that were carried out are described. Finally in Chapter 9 the conclusions of the work are presented, and some suggestions for further research are given.

Abstract: The purpose of this document is to present an overview of the SURFnet4 requirements with respect to ILMI, SNMP and MIBs issues.

Abstract: This technical report bundles the five reports that were written for two SURFnet4 projects in 1997. Each report discusses a different research aspect of the SURFnet4 ATM net-work. The topics are 1) the Architecture of a ATM PVC Management Tool, 2) Reporting on the Use of the ATM Network, 3) SVCs in a Production Environment, 4) Quality of Service Measures, 5) Operation and Maintenance (OAM).

Abstract: Before you start reading this white paper, lock the door! And make sure that none of your networking vendor's sales reps are around, because they'll go to any lengths to insure you don't learn what's in this document. For the first time, the secrets behind the onslaught of marketing for "switching" technologies will be revealed. The term "switching" has been applied to so many elements of network infrastructure that it's become nearly impossible to define. We have switching hubs, multilayer switches, Layer 3 switches, Layer 4 switches, routing switches, cell switches and more. The question most frequently asked at industry trade shows is no longer "what does your product do?", it's "what kind of switch do you have?". So before diving into today's switching terminology soup, let's review some basics.

Abstract: The Differentiated Services architecture allows a service provider to configure new services dynamically using a policy protocol. This benefit, however, may not be fully realized if the service provider can not charge for the services, or need a high effort to update its billing system to charge for the services. Thus, there is a real need for a flexible billing architecture to complement the flexibility offered by the differen-tiated service model. To meet this need, a policy-based billing architecture is proposed in this paper. This architecture allows a service provider to define policies for configuring various processes of a billing system based on the charging and pricing schemes used for individual services. It is demonstrated how the architecture supports flat-rate, duration-based and volume-based charging, and also both static and dynamic pricing. Definitions of policies for various charging and pricing schemes are discussed and the potential complexity of each of them is analyzed. Based on the complexity analysis we recommend the least complex charging schemes for four classes of differentiated services, which have been proposed for meeting different application requirements.

Abstract: Management scripts are being used as the major means to realize the powerful con- cept of management by delegation. Many script delegation frameworks are proposed and experimented with for various network management standards, notably, the SNMP, OSI, and CORBA. More proposals and research are underway. The major problem with these scripting frameworks is that most of these frameworks are, in a sense, aiming at rapidly introducing remote scripting capability to existing management frameworks; therefore, true integration between the two are not achieved. We argue that an integrated scripting framework can provide more power and ease of use to the network managers and applications. In this paper, we explore various ways to inte- grate the scripting and management frameworks. This is based on our decomposition of the management information model, and a de nition of the functional architecture of the general scripting framework. We also present a perspective on different levels of integration.