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IPANA-IP ATM Network Archtitectures


Conference papers


This paper was presented in IEEE Africon '96, September 25-27, 1996.

In this paper, several performance measurements of ATM (Asynchronous Transfer Mode) networks are performed and analysed. Especially, measurement of the buffer size, the traffic management functions and the cell transfer delay in a switching system are studied as a function of various traffic patterns and loading levels. These values have great importance for establishing reliable media for broadband traffic and contributing to the implementation of services in ATM networks.

M Luoma & M Ilvesmäki: Simplified Management of ATM traffic

This paper will be presented in SPIE Voice, Video & Data Communications '97, November 2-5, 1997.

ATM has been under a thorough standardization process for more than ten years. Looking at it now, what have we achieved during this time period? Originally ATM was meant to be an easy and an efficient protocol enabling varying services over a single network. What it is turning to be is ‘yet another ISDN’-- network full of hopes and promises but too difficult to implement and expensive to market. The fact is that more and more ‘nice features’ are implemented on the cost of overloading network with hard management procedures. Therefore we need to adopt a new approach. This approach keeps a strong reminds on ‘what is necessary.' This paper presents starting points for an alternative approach to the traffic management. We refer to this approach as ‘the minimum management principle.' Choosing of the suitable service classes for the ATM network is made difficult by the fact that the more services one implements the more management he needs. This is especially true for the variable bit rate connections that are usually treated based on the stochastic models. Stochastic model, at its best, can only reveal momentary characteristics in the traffic stream not the long range behavior of it. Our assumption is that ATM will move towards Internet in the sense that strict values for quality make little or no sense in the future. Therefore stochastic modeling of variable bit rate connections seems to be useless. Nevertheless we see that some traffic needs to have strict guarantees and that only economic way of doing so is to use PCR allocation.

M Ilvesmäki, K Kilkki & M Luoma: Packets or Ports - The decisions of IP switching

This paper will be presented in SPIE Voice, Video & Data Communications '97, November 2-5, 1997.

One of the most important network elements in the Internet are the routers which do relaying of IP packets. Because of growth of the Internet routers currently experience serious problems in relaying traffic in a satisfying speed. The idea of switching Internet traffic flows has recently been introduced and a new technology called IP switching has emerged. Several differing technological solutions have been suggested. In this paper we describe and compare two methods in flow-based IP switching to make the decisions whether to switch internet traffic flows to separate ATM-connections. Traffic measurements are made in two networks of varying size and based on a specific three-stage flow analysis we suggest that the decision to switch should be made as flexible as possible due to the expected diversity of traffic profiles in different parts of the network. This way the optimal service cluster could be switched and router resources could be optimally utilized. A simple model to determine workload to an IP switch is introduced. Using this model we see that the workload of the flow setup component and the routing component may be optimized, if we use flexible methods to determine the flows that are to be separately switched.

M Ilvesmäki & M Luoma: IP switching in a simplified ATM environment

This paper will be presented in SPIE Voice, Video & Data Communications '97, November 2-5, 1997.

Key issues in the current development of Internet seem to be its capability to scale and to support new real-time or near real-time applications like video- and audio conferencing. There are two factors that affect these qualities: one is the ability to distinguish which connections should be switched and the other is the effective control over network resources. ATM is a serious attempt to standardize global multiservice networks. This attempt seems to suit well for the future Internet. ATM was originally meant to be an easy and an efficient protocol but it is now turning to be ‘yet another ISDN’. More and more features are implemented to ATM resulting in the overloading of the network with management procedures. Therefore a new approach needs to be taken. In this approach a strong reminder of ‘what is necessary’ needs to be kept in mind. This paper presents an alternative, simpler approach to the ATM traffic management and introduces some suggestions how to map Internet applications to simplified ATM environment using an advanced IP switching concept.

R. Kantola, J. C. Requena, N. Beijar: A Common Numbering Infrastructure for IN and IP networks

IEEE Intelligent Network Workshop 2000 (IN2000). May 7-11, 2000, Cape Town, South Africa.

This paper describes and analyses a solution to the problem of interoperability between Intelligent Networks and Voice over IP networks for directory-based routing. We will present an architecture based on a distributed database on the circuit switched network and the IP network. The aim of the solution is to provide efficient service management, efficient routing for 800- and cellular numbers and personal number portability between both architectures. As an introduction, some directory-based solutions for number portability are presented and especially the requirements for a directory-based routing solution are discussed. Arguments for and against using directories and some design issues are presented. We then develop and present an infrastructure for directory-based routing that in addition to number portability also provides efficient service management and routing in a hybrid (SCN, IP voice) network. This paper is mainly intended as a framework of a project under development in our Laboratory.

The solution is based on different approaches for each network. In the IP network we use the Telephony Routing over IP (TRIP) protocol developed by IETF. Additionally, the described architecture is open for inclusion of the Enum protocol that is under development. For the circuit switched network, we suggest a new protocol called Circuit Telephony Routing Information Protocol (CTRIP). The protocol provides a distributed method for synchronizing routing information between databases located in the SDFs. Furthermore, we define the operation of numbering gateways, which are used for transferring number information between the two network types. The numbering gateway functionality is intended as a logical entity in the gateway decomposition model. Due to the different needs in circuit switched networks and IP networks, also the number portability information differs. Precisely defined algorithms are required for mapping information between the protocols to avoid routing loops and inefficient routing. We utilize the Server Cache Synchronization Protocol (SCSP) as the common element for data synchronization and replication for distributed entities.

For Number Portability it is essential to use and maintain data that is shared among many applications while the data resides in different physical locations. The introduction of Voice over IP services increases the requirements for managing large amounts of data. To facilitate user mobility, the data is distributed over different locations following directory structures where the information is close to the customer location. The main goal is to achieve a service that is accessible from everywhere, independently of the location of the user accessing the service. For that reason, we are implementing the TRIP and CTRIP based on the SCSP. In this paper its actual development is discussed. We point out the final application for the whole solution in a mixed IP/ISDN network. We also review some alternative approaches to directory services. In conclusion we propose the SCSP as the basic component for exchanging information about portable numbers between IN and IP. We want to emphasize the key role of synchronizing and updating the user information in the emerging global communications infrastructure.

P. Zhang, R. Kantola, Z. Ma: Design and Implementation of A New Routing Simulator

2000 SCS Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS'2K). July 16-20, 2000, Vancouver, Canada.

In this paper, we present the design and implementation of a new QoS_based Routing Simulator (QRS). Based on the core of a public routing simulator – MaRS  , we have developed QRS by designing and implementing new QoS-related components, i. e., resource reservation (RSVP), resource management (RM), QoS routing algorithms, traffic scheduling and real-time traffic workload. QRS allows users to configure the parameters of a QoS guaranteed network, where the dynamics of QoS routing algorithms as well as traffic management algorithms can be investigated. We also present some simulation results obtained by using QRS.

P. Zhang, R. Kantola: Mechanisms for Inter-Domain QoS Routing in Differentiated Service Networks

1st International workshop on  quality of future Internet Services (QofIS'2000). September 25-26, 2000, Berlin, Germany.

In order to provide various services with different quality requirements, the current Internet is expected to turn into a QoS based Internet under the Differentiated Service (DiffServ) architecture. A variety of works have been done in the field of constraint based routing  to provide QoS guaranteed or assured services by developing novel routing protocols and algorithms. However, most of these efforts focus on intra-domain routing rather than inter-domain routing. In this paper, we discuss issues of finding routes with QoS requirements among multiple domains, called inter-domain QoS routing. We first investigate the needs and problems faced when introducing inter-domain QoS routing into the Internet. Then, we present a model for  inter-domain QoS routing and describe its building blocks. Finally, we present five mechanisms for operating inter-domain QoS routing in  DiffServ networks.

P. Zhang, R. Kantola: Building MPLS VPNs with QoS Routing Capability

Fifth International Symposium on Interworking (Interworking'2000). October 3-6, 2000, Bergen, Norway.

Recently MPLS is used for building up VPNs in IP backbone, called MPLS VPNs. In this paper, we discuss issues on finding routes with QoS requirements (i.e., QoS routing) in MPLS VPNs. We first present background on MPLS VPNs as well as QoS routing.  Then we discuss both the benefits and problems resulted from introducing QoS routing into MPLS VPNs. We particularly present an architecture of MPLS VPNs with QoS routing capability, on which we discuss some important issues on running QoS routing in MPLS VPNs.


Mika Ilvesmäki: The use of ATM-technology in switching of internet traffic, Espoo 1996.

Several applications of the ATM-technology in switching and relaying the internet-traffic are studied in this work including IP over ATM, ATM Forum LAN emulation and IP-switching. The applicability of these techniques is resolved through traffic measurements of real computer networks of different magnitude. Measurements show that traffic and service profiles in the internet are heavily dependent on the size of the network, the habits of the users and the applications used. Measurements indicate that the workload of routers decreases over 50 % if IP-switching is used. On the other hand the identification, classification and the switching criteria of a traffic flow, or an IP-flow, should be further studied to enable the use of IP-switching in different kinds of networks. Also the interoperability between IP-switching equipment and other network components requires special attention.

Keywords: ATM, B-ISDN, IP-switching, internet, traffic measurements, routing

Jose M Costa Requena: An Implementation of the Server Cache Synchronization Protocol (SCSP) -RFC 2334- , Espoo 1999.

An implementation of the Server Cache Synchronisation Protocol (SCSP) is presented in this Master Thesis. Initially, the SCSP algorithm establishes the data synchronisation among a set of server entities of a particular protocol which are bound to a Server Group (SG). After that it maintains an actively mirroring state of any change in every cache information that form the SG. The program is based on an object-oriented software environment. This leads to a modular implementation. Different processes take place between each "Local Server" (LS) and its "Direct Connected Server" (DCS). The protocol code (which is written in C++) facilitates an easy translation to new communication architectures and services in a rapidly changing scenario. The basic structures used by the program were developed following the Management Information Base (MIB) specifications. The purpose is to permit later interactions with an SNMP agent, which checks the correct functioning of the protocol. The most important application of this software package is focused in the IP Telephony and the new emerging directory services. For those services it is necessary to manage large amounts of information that is stored in distributed databases that need to be efficiently updated and replicated.

Keywords: C++,SNMP, MIB, SG,UNIX

Inmaculada Espigares del Pozo: An implementation of the Internet Call Waiting service using SIP,Espoo 1999.

We have studied the SIP for the purpose of evaluating it and to make an implementation of a new service, the Internet Call Waiting (ICW). It is a useful solution for the calls that otherwise would be lost when the line is busy and also for rejecting undesirable incoming calls. On the other hand, it is a way of not wasting network resources and contributing to call completion. Thus, pop-up dialogue boxes are presented to make it simpler and easier to the user whose satisfaction is always an important objective for an IP based service. For service implementation, as the main tool, we have used the XML language. XML is considered one of the best languages for describing complex data relationships. We have also chosen XML because it is easily extended, flexible and because it has a text-based syntax. The complete project consists of a JAVA program that implements an UAS/UAC running in a PC and also an extension (embedding the XML parser)of the SIP server written in C borrowed from Columbia University to handle the scripts written in XML defining the service required by the users. In conclusion, we have tried to use the most efficient tools and mechanisms to complete this work as we consider that time and money are resources to take into account when developing the services of the new era.

Keywords: XML,script,java,C,parser,service

Full papers are either in PostScript or PDF form.

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