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IMELIO - Internet MEchanisms for quaLity and InterOperability

Journal papers

Raimo Kantola, Jose Costa Requena, Nicklas Beijar: Interoperable routing for IN and IP Telephony, Computer Networks, 2001

This paper discusses the problem of interoperability of IP Telephony and Switched Circuit Networks in the area of routing information. We describe and analyze a solution for directory-based routing. We will present an architecture based on a distributed database on the switched circuit network and the IP network. The aim of the solution is to provide efficient service management, close to optimal routing for all calls including calls to 800- and cellular numbers and personal number portability between both network technologies. The solution is based on similar but differing in detail 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. Furthermore, we propose numbering gateways for transferring number information between the two network types. We utilize the Server Cache Synchronization Protocol (SCSP) as the common element for data synchronization and replication among distributed entities. We also discuss briefly the design of a test implementation of the proposed infrastructure functions and protocols under development in our Laboratory. In conclusion, we propose to design a common interoperable routing information infrastructure for the emerging hybrid SCN/IP Telephony network.

Keywords: Voice over IP; number portability; directory; data replication; data synchronization; protocol; routing; SCSP; TRIP; CTRIP; ENUM

Conference papers

Zhansong Ma, Peng Zhang, Raimo Kantola: Influence of Link State Updating on the Performance and Cost of QoS Routing in an Intranet. 2001 IEEE Workshop on High Performance Switching and Routing (HPSR 2001), Dallas, Texas USA, May 29-31, 2001

In recent years, QoS  routing has been regarded as an essential enhancing mechanism for providing differentiated QoS in the IP networks. QoS routing needs link state updating (LSU) algorithms for acquiring accurate link state information (e.g., available link bandwidth) to compute routes. However, an unsuitable link state updating also brings excess computation and communication cost so that seriously degrades the performance of QoS routing. In this paper, we present four link state update algorithms for QoS routing in an Intranet, i.e., period based (PB), threshold based (TB), equal class based (ECB), and unequal class based (UCB) updating. By doing extensive simulations, we investigate and compare their impact on the performance and cost of on-demand QoS routing in an intranet. Our simulation results prove that QoS routing can achieve both high performance and low cost under the careful selection of LSU algorithms and their parameters.

Keywords: QoS routing, link state updating algorithms, performance and cost

Peng Zhang, Zhansong Ma, Raimo Kantola: Designing A New Routing Simulator for DiffServ MPLS Networks. 2001 International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS 2001), July 15-19, Orlando, Florida USA

In this paper, we present the design and implementation of a new routing simulator called Extended QoS_based Routing Simulator (EQRS). EQRS is a discrete-event simulator developed for studying constraint based routing in the Internet. It is an upgraded version of QRS – QoS_based Routing Simulator [1]. Our objective in this version is to provide new capabilities that enable simulating DiffServ MPLS networks. EQRS allows users to configure parameters of DiffServ MPLS networks, where the dynamics of constraint based routing algorithms as well as traffic engineering mechanisms can be investigated. Particularly, with the help of EQRS, we investigate the performance and cost of QoS routing under a QoS routing algorithm and a specific link state update (LSU) algorithm. The simulation results prove that: 1) QoS routing acheives better network performance under careful configuration; 2) the simulator is suitable for modeling, designing and evaluating DiffServ MPLS networks.

Keywords: Differentiated Services (DiffServ), Multi Protocol Label Switching (MPLS), Constraint Based Routing, Quality of Service, Link State Update (LSU)

Mika Ilvesmäki, Sampo Kaikkonen: The length of measurement period to determine the application profile for traffic classification in the Internet, 2001 International Conference on Communications (ICC 2001), Helsinki.

We discuss the aspect of measurement period length in the detection of dynamic application profiles in the future Internet solutions requiring automatic network based traffic differentiation. We base the analysis on a measurement-based method to form dynamic application profiles and observe the effect of the measurement period to the quantity and quality on the dynamic application profile. We see that the detected traffic profiles are of reasonable size and contain relevant applications. The results indicate that the measurement period has to be several hours in length and that the measurement process should be ongoing to ensure valid and stabilized application set.

Keywords: Traffic classification, traffic measurements, traffic characterization


Zhansong Ma: Performance/Cost Analysis of QoS Routing in the Intranet, Espoo 2000.

QoS routing has been regarded as an important part in the evolution of QoS-based service offerings in the Internet. It computes paths that are subject to QoS requirements and can improve the utilization of network resources. Besides benefits, QoS routing also results in cost. The main cost  of QoS routing includes path computation cost, link state update cost and storage cost. Before deploying QoS routing into the Internet, the performance/cost ratio of QoS routing still needs careful study. This thesis aims to investigate this problem through simulation study. This thesis begins with an overview of QoS in the Internet, in which some QoS related components, e.g., Integrated Services with Resource Reservation Protocol, Differentiated Services, MultiProtocol Label Switching and QoS routing, etc., are introduced. Then, the problem of QoS routing in the Internet is investigated. Also, some issues on implementing QoS routing in the Internet are presented and discussed. In order to study the performance/cost ratio of QoS routing, we designed and implemented a QoS routing simulator. Particularly, two routing algorithms and four link state update algorithms were implemented. With the help of the simulator, we analyzed the factors that affect the performance/cost ratio of QoS routing. As results, we found that the cost of QoS routing is very sensitive to network size, that the cost can be significantly reduced by the use of suitable link state update algorithms, that frequent requests cause high cost, that traffic pattern is another factor that affects QoS routing cost. Some results presented in this thesis can be used for guiding the deployment of QoS routing in IP networks.

Keywords: Quality of Service, IntServ, RSVP, DiffServ, MPLS, QoS routing

Julio Ramirez Yebenes: Scalability Analysis of the Server Cache Synchronization Protocol, Espoo 2001.

Keywords: SCSP, Threads, Transpapency, Portability, Scalability, Performance.

Juan Ventura Agustina: Impact of GPRS on Existing GSM Services, Espoo 2001.

Keywords: GPRS, GSM, channel allocation, GoS, handover performance, network planning.

Full papers are either in PostScript or PDF format.

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