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University: Technical University of Denmark
Name of sponsoring Professor: Lars Dittmann
Department: DTU Fotonik Department of Photonics Engineering
(Note: Prior to January 1, 2008, the department was named COM·DTU Department of Communications, Optics and Materials)

Research:

With the enormous growth in the number of users of the Internet, next generation Internet must be considered. By combining MPLS with optical switching technologies, high capacity networks can be implemented. We're working on a  hierarchical network concept, which supports topology aggregation and traffic engineering schemes. This work, which is still ongoing, attempts to by simulation evaluate the amount of control traffic overhead while computational complexity, convergence time, and route optimality are also taken into acount. The work here aims at quantifying this by OPNET.This work can be split into the following tasks:

  • Hierarchical routing
  • Traffic bundling
  • MPLS in hierarchical topologies
  • MPLS and GMPLS integration
  • Optical switch node architectures
  • Internet QoS

These tasks are described in some detail below:

Hierarchical routing

Quality of Service is of major concern for future networks. Within the European Research project DAVID we are using OPNET to model layered networks. The goals are:

  • Impact of logical network hierarchies on the amount of routing information. 
  • Constraint based routing in hierarchical networks. When routing is based on aggregated topology information how is the resulting connections compared to networks, where the routing protocol has full knowledge of the network topology?

Traffic bundling

When aggregating traffic from many sources while considering delay constraints a number of things such as queuing systems structure and scheduling must be taken into consideration. We have modeled a device which can aggregate traffic from a number of low bit rate source to one high bit rate stream. The device contains a number of queues and a scheduler that selects which queue to extract packets from.

We are investigating the following:

  • Impact of input traffic patterns on delay
  • Pros and cons of various scheduling schemes. 
  • Queuing systems structures

For results and further information please see authored papers.

MPLS in hierarchical topologies

MPLS is an interesting concept for introdusing QoS in networks. The work on MPLS is focused on multidomain, hierarchical MPLS networks. This hierarchical structure subdivides the network into domains. The goal is to measure the amount of overhead in terms of signalling within doamins (intra domain signalling) and between domains (inter domain signalling). The work is carried out within the European Research project DAVID.We are currently working on

  • Methods for measuring MPLS signalling overhead with OPNET
  • Methods for defining multi-domain, MPLS networks in OPNET

MPLS and GMPLS integration

GMPLS is a generalization of the MPLS to also cover circuit switched networks. We are currently working on:

  • Implementing GMPLS in OPNET
  • Integrating the GMPLS model with the OPNET MPLS models, so that paths can be set up through mixed MPLS/GMPLS networks.

For results and further information please see authored papers. 

Optical Switch node architectures

In all-optical networks the architecture of the switching nodes determines the properties of the entire network. By using OPNET modeler we investigate issues like buffer structures in all-optical switching devices. 

For results and further information please see authored papers. 

Internet QoS

Application level QoS is very inportant when investigating and bechmarking Internet sertvises. Simulation is one of the only means by which you can get predictable results from such an analysis. We er looking into INternet acces in as well wires as wireless environments. We are looking into doing some real life measurements to validate the simulation sesults.  

Teaching:

OPNET is used for teaching courses as well as for project work. Currently, OPNET software is used in the courses: 

These courses are described in further detail below. 

For a list of bachelor and master theses that included modeling work with OPNET Modeler and/or WDMGuru see Bachelor and Master theses below.

Network Modeling and simulation

The course '34354 Network Modeling and Simulations' is dedicated to teaching the students how to use OPNET. The course started in september 2003 and in the spring semester we will be offering the course for 7th time. The course is based on lectures, hand-on labs and a modeling/simulation project. Below is an overview of the lectures: 

  • Introduction to the course. Some basic introduction to network simulation and OPNET Modeler
  • A first encounter with OPNET: tutorials
  • FSM modeling methodology
  • Hands-on: Implementation of a CSMA protocol
  • OPNET Modeler topics: Statistics, attributes, packets
  • OPNET Modeler topics: Basic debugging, Simulation Sequences, Auto Addressing
  • OPNET Modeler topics: Dynamic processes, link-models
  • OPNET Modeler topics: Interface Control Information (ICI), Failure/Recovery, Topology 
  • Modeling efficiency techniques, advanced model debugging
  • Presentation of possible topics for student's projects

Below is a list of the simulation projects in this course since 2005:

  • 2005
    • Contention resolution mechanisms in optical packet switches
    • Signaling protocol extensions for converter-saving wavelength assignment in GMPLS optical netwroks
    • Open Shortest Path First (OSPF)
    • QoS scheduling
    • EPON topology and bandwidth Allocation schemes design
    • A mini edition of DSR protocol designed for OPNET
    • DSDV simulation in OPNET
    • PAcket level simulation, evaluation adn optimzation for Ad-hoc On Demand Vector Routing Protocol
    • 802.16 uplink scheduling modelling and evaluation
    • Ad-hoc routing protocol (AODV)
    • Implementation of contention resolution policies for optical burst switched networks
  • 2006
    • Uplink QoS Scheduling in 802.16 Systems
    • Investigation for Routing Information packet of AODV protocol
    • The Streaming Control Transport Protocol and its DoS Resilience
    • 802.11 DCF MAC Performance Evaluation Based on Opnet Simulation
    • Belastningsbalancering baseret på myrer
    • Gratuitous AODV
    • Comparison of the Reno and NewReno algorithms for TCP Congestion Control
    • HSRP
  • 2007
    • Streaming Control Transport Protocol
  • 2008
    • UMTS-WLAN handover delay measurement using OPNET Modeler
    • IEEE 802.16 Fixed Broadband Wireless Access
    • Ad-Hoc On Demand Distance Vector Routing Protocol (AODV)

  • 2009

    • Traffic Modeling and Analysis of IMS Presence Server

    • The Proposal of the Two Working Paths MPLS-TP Ring-Based Protection and the Flow-based OAM Function

    • UPnP Signaling Reservation and Preemption

    • Routing Information Protocol - Convergence measurement

    • SCTP: Stream Control Transmission Protocol - Multistreaming functionality and influence on Head of Line blocking effect

    • TCP Congestion Control

    • Bluetooth Baseband Layer OPNET simulation

    • Resilience to Denial of Service of SCTP and TCP

Optical  Networks

In '34353 Optical networks' we use WDMGuru to gain an understanding of optical networks. In the course, there is a mandatory exercise, which has the following purposes:

  • The student should aquire skills in the Network Planning tool WDM Guru to understand how such tools can aid a network designer.
  • The project should illustrate issues covered in the course:
    • Network layering
    • Resilience
    • Optical transparancy limititations ( w.r.t Optical Switching and Transmission)
    • Network Planning

You can download the full project description here and the WDM guru files here. One example solution that the students came up with can bee seen here. 

Engineering Practices

The 34302 Engineering Practices course is a introductory course for students on the 1st semester of the university's bachelorprogramme in IT and Communication Technology. In this course, the students must do a number of small projects within different areas of the bachelorprogramme. The topic of one of these projects is Internet routing, where the students must experiment with static routing, dynamic routing, effects of routing loops and NAPT using OPNET Modeler. Other topics investigated with the aid of OPNET Modeler is performance comparisons between different types of LANs, e.g., hub-based LANs, switch-based LANs and wireless LANs (WiFi). Some different Modeler-projects are provided for the students. The students are then required to configure the nodes, e.g., assign IP addresses, static routes, enable dynamic routing, etc., and run simulations to verify the their configurations

Summer School in Telecommunications

In the summer of 2008, DTU Fotonik will host for the second time a summer school in telecommunications. Students from foreign universities are invited to come to DTU Fotonik for a period of 3 week, where the students would participate in 2 different projects within the area of telecommunications. One of these projects is about network modelling and simulations, where the students will design and implement a small point-to-point communication system in OPNET Modeler, and subsequently perform simulations with this model. The project description is here.

Bachelor and Master Theses:

Below is a list of completed bachelor theses and master theses covering work that used OPNET Modeler and/or OPNET WDMGuru. (Note: Some of these are in danish)

  • Bachelor theses:
    • Andreas O. Rytlig and Troels M. Trebbien, "Simulering af RSVP-TE i optiske netværk" (submitted June 2008)
    • Christian Bækbo and Hördur Mar Gestsson, "Traffic Shaping and Policing in Data Networks" (submitted June 2008)
    • Jon C. Staffeldt, "Network planning for MPLS core networks" (submitted June 2006)
    • Lei Zhang and Amara Bjergskov, "UMTS transport channel simulation in OPNET", (submitted December 2002)
  • Master theses:
    • X. Li, "Multidomain Network Survivability" (submitted February 2008)
    • B. Ö. Arnarsson and Ý. Sigurðarson, "Analysis of an IP Mobility Solution for IEEE 802.11 and IEEE 802.16 Networks" (submitted August 2007)
    • M. H. Nielsen, "En modelleringsbaseret tilgang til evaluering af fairness af scheduling- og AQM algoritmer for ressourcedeling in IP netværk" (submitted October 2006)
    • A. V. Manolova, "Contention Resolution in OBS Networks with GMPLS Control" (submitted September 2006)
    • M. Kähler, J. Thousig, "QoS handling in 802.11 wireless LANs" (submitted March 2006)
    • C. V. Petersen, "QoS in MPLS" (submitted February 2006)
    • K. K. Svendsen, "Performance Evaluation of IPv6 Mobility Schemes" (submitted February 2006)
    • J. Nielsen, "Signalling architecture for UMTS networks" (submitted September 2005)
    • V. Bailet, "A study of the COmmon Gateway Architecture for Mobile Ad-hoc Networks" (submitted August 2005)
    • U. Ansari, "Performance Analysis of TETRA (DMO) over WLAN" (submitted August 2005)
    • U. Shahid, "Modelling of High Speed Downlink Packet Access (HSDPA) in UMTS networks" (submitted July 2005)
    • F. Jovanoski, "Modelling of UMTS core networks" (submitted July 2005)
    • S. Ruepp, "Network Restoration" (submitted October 2004)
    • F. Clementson, M. Nilsson, "Performance Modelling of QoS in wireless LANs" (submitted September 2004)
    • A. Schmidt, "UMTS and WLAN interoperability" (submitted July 2004)
    • Shou Li, "Performance Modelling of TETRA Air Interface" (submitted June 2004)
    • Lei,  "Modeling of SCTP protocol" (submitted December 2003)
    • Emilia Dobranowska, "Traffic engineering in MPLS networks", (submitted August 2003) (intro) (part I) (Part II) (Appendices)
    • Stijn N. P. Van Cauwenberge, "Simulation study of soft handover in UMTS", (submitted July 2003)
    • Brian Nors Jensen and Karl-Kristian Jensen, "Reliable Multilink Traffic Shaper", (submitted June 2003)
    • Iker Mayordomo, "Simulation study of TCP with PEPs (performance enhancing proxies)", (submitted May 2003)
    • Camilla Ceruti, "Ad hoc networks", (submitted April 2003)
    • Fenling Yang, "Packet over ring based SONET/SDH networks", (submitted October 2001)
    • Jens Krenk, "Quality of Service in UMTS networks", (submitted August 2001)
    • Kristian Sveistrup, "Load Balancing in multi path switch systems", (submitted August 2001)
    • Henrik Voldby, "MAC protocols for Resilient Packet Rings", (submitted May 2001)

Authored papers

This is a list of authored papers containing OPNET simulation results since 2006. For earlier papers, please see our old page describing our OPNET use.

  • 2009
    • N. Andriolli, P. Castoldi, H. Harai, J. Buron, and S. Ruepp, "GMPLS-based packet contention resolution in connection-oriented OPS networks", Journal of Optical Networking Vol. 8, Issue. 1, pp. 14–25, Jan. 2009
    • A.Manolova, S.Ruepp and L.Dittmann, "On the Efficiency of BGP-TE Extensions for GMPLS Multi-domain Routing," in IEEE Proc. 13th Conference on Optical Network Design and Modeling (ONDM), February 2009.
    • A.Manolova, S.Ruepp, and L.Dittmann, "TE-enhanced Path Selection for QoS Provisioning in Multi-domain GMPLS Networks," in IEEE Proc. Optical Fiber Communication Conference/National Fiber Optic Engineering Conference (OPF/NFOEC), March 2009.
    • A.Manolova, E.Calle, S.Ruepp, J.Marzo, and L.Dittmann, "Location-based Restoration Mechanism for Multi-domain GMPLS Networks," in IEEE Proc. International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS), July 2009.
    • Hao Yu, Ying Yan, and Michael S. Berger, "IPTV Traffic Management Using Topology-Based Hierarchical Scheduling in Carrier Ethernet Transport Networks", ChinaCom 2009, August 2009
    • S. Ruepp, A. Koster, N. Andriolli, and A.V. Manolova, “Prioritizing Connection Requests in GMPLS-Controlled Optical Networks”, in Proceedings of Photonics in Switching 2009, Tirrenia, Italy, September 2009
    • A.Manolova, S.Ruepp, and L.Dittmann, "Performance Comparison of Multi-domain Routing Schemes in GMPLS Networks with BGP," in IEEE Proc. 17th International Conference on Photonics in Switching (PS), September 2009.
    • Hao Yu, Ying Yan, and Michael S. Berger, "Topology-based Hierarchical Scheduling Using Deficit Round Robin: Flow Protection and Isolation for Triple Play Service", ICFIN 2009, October 2009
    • L. Brewka, H. Wessing, and L. Dittmann, “Signaling performance of UPnP QoS architecture,” in Third IEEE International Conference on Advanced Networks and Telecommunication Systems (ANTS), New Delhi, India, December 2009
  • 2008
    • X. Li, S. Ruepp, L. Dittmann, and A.V. Manolova: "Survivability-Enhancing Routing Scheme for Multi-Domain Networks", in Proceedings of Globecom 2008, New Orleans, USA, November 2008
    • J. Buron, S. Ruepp, H. Wessing, N. Andriolli, A.V. Manolova, and L. Dittmann: "Wavelength Converter Placement in Optical Networks with Dynamic Traffic", in Proceedings of APOC 2008, Hangzhou, China, October 2008
    • A. Koster and S. Ruepp: “Benchmarking RWA Strategies for Dynamically Controlled Optical Networks”, in Proceedings of NETWORKS 2008, Budapest, Hungary, September 2008
    • L. Staalhagen: "Modelling and Simulation of an Adaptive Scheme for PRMA", OPNETWORKS 2008, August 2008
    • X. Li, S. Ruepp, A.V. Manolova, L. Dittmann: "OPNET Model of Multi-domain Routing with Enhanced Survivability", OPNETWORKS 2008, August 2008
    • L. Staalhagen: "Combining OPNET Modeler with packet analysis tools", OPNETWORKS 2008, August 2008
    • H. Yu, Y. Yan, M. Berger: "IPTV Traffic Management in Carrier Ethernet Transport Networks", OPNETWORKS 2008, August 2008 (This paper received the "Best Technical Paper" award at OPNETWORKS 2008) 
    • H. Yu, L. Dittmann: "Design and Simulation of a Protocol for Home Environment Network", OPNETWORKS 2008, August 2008
    • S. Ruepp, N. Andriolli, J. Buron, L. Dittmann, L. Ellegård: “Restoration in All-Optical GMPLS Networks with Limited Wavelength Conversion”, Computer Networks Special Issue on Opportunities and Challenges in Optical Networks, vol. 52, no. 10, pp. 1951–1964, July 2008
    • C. Raffaelli; K. Vlachos; N. Andriolli; J. Buron; R. van Caenegem ; G. Danilewicz ; J. M. Finochietto; J. Garcia-Haro; D. Klonidis ; M. O'Mahony; G. Maier; A. Pattavina; P. Pavon-Marino; S. Ruepp; M. Savi; M. Scaffardi; I. Tomkos; A. Tzanakaki; L. Wosinska; K. Yannopoulos; F. Neri: “Photonics in Switching: architectures, technologies and systems - The e-Photon/ONe+ research results”, Computer Networks Special Issue on Opportunities and Challenges in Optical Networks, vol. 52, no. 10, pp. 1873–1890, July 2008
    • Hua Wang, Villy B. Iversen: ”Hierarchical Downlink Resource Management Framework for OFDMA based WiMAX Systems” IEEE Wireless Communications & Network Conference ( IEEE WCNC 2008), Las Vegas, USA, March 2008
    • S. Ruepp, J. Buron, N. Andriolli, L. Dittmann. “Nodal Stub-Release in All-Optical Networks”, IEEE Communication Letters, vol. 12, no. 1, Jan. 2008
  • 2007
    • Hua Wang, Lars Dittmann: “Adaptive Radio Resource Allocation in Hierarchical QoS Scheduling for IEEE 802.16 Systems”, IEEE Global Telecommunications Conference (IEEE GLOBECOM 2007), Washington D.C., USA, November 2007
    • Hua Wang: “Priority-based Resource Allocation for RT and NRT Traffics in OFDMA Systems”, The 3rd International Conference on Wireless Communications, Networking and Mobile Computing (IEEE WiCOM 2007), Shanghai, China, September 2007
    • A. V. Manolova, J. Buron, S. Ruepp, L. Dittmann, L. Ellegård, "Segmentation-based Path Switching Mechanism for Reduced Data Losses in OBS Networks", Proceedings of IFIP-TC6 Conference on Optical Network Design and Modelling (ONDM 2007), Athens 2007.
    • A. V. Manolova, J. Buron, S. Ruepp, L. Dittmann, L. Ellegård, "Modeling contention resolution strategies in Optical burst switching networks", OPNETWORKS 2007, August 2007.
    • S. Ruepp, J. Buron, N. Andriolli, H. Wessing,. “Span Restoration in Optical Networks with Limited Wavelength Conversion”, Proceedings of Chinacom 2007, Shanghai, China, August 2007.
    • P. Castoldi, N. Andriolli, I. Cerutti, N. Sambo, L. Valcarenghi, A. Giorgetti, S. Ruepp, J. Buron ”A Framework for Label Preference in GMPLS Controlled Optical Networks”, Proceedings of 2007 International Conference on Transparent Optical Networks (ICTON 2007), Rome, Italy, July 2007.
  • 2006
    • N. Andriolli, J. Buron, S. Ruepp, F. Cugini, L. Valcarenghi, P. Castoldi, "Label Preference Schemes in GMPLS Controlled Networks", IEEE Comm. Letters, vol. 10, no. 12, December 2006
    • S. Ruepp, J. Buron and N. Andriolli, “ Increasing Restorability for Local-to-Egress Restoration in GMPLS Controlled Networks with Limited Wavelength Conversion”, Proceedings of International Conference of Communication Systems (ICCS), Singapore, October/November 2006.
    • J. Buron, S. Ruepp, N. Andriolli, "Blocking Reduction of Span Restoration Requests in GMPLS Controlled WDM Optical Networks", Proc. of European Conference on Optical Networking (ECOC) 2006, Cannes, France, September 2006.
    • J. Buron, S. Ruepp, A. V. Manolova, “Teaching Cost-effective and Resilient Network Design with OPNET WDM Guru”, Proc. of OPNETWORK 2006, Session 1020, Washington DC, USA, August 2006.
    • S. Ruepp, N. Andriolli and J. Buron, “Signaling Protocol Extensions Enhancing Provisioning and Recovery in GMPLS Optical Networks”, Proc. of OPNETWORK 2006, Session 1339, Washington DC, USA, August 2006.
    • N. Andriolli, J. Buron, S. Ruepp, P. Castoldi, "Modeling GMPLS-Controlled Optical Packet Switched (OPS) Networks, Proc. of OPNETWORK 2006, Session 1339, Washington DC, USA, August 2006.
    • S. Ruepp, J. Buron, and N. Andriolli, "Wavelength-Converter Saving Span Restoration in GMPLS Controlled WDM Optical Networks", COIN-NGNCON 2006, Jeju, South Korea, July 2006.
    • N. Andriolli, J. Buron, S. Ruepp, F. Cugini, L. Valcarenghi and P. Castoldi, 'Signalling protocol extensions for converter-saving wavelength assignment in GMPLS optical networks', HPSR 2006, Poznan, Poland, June 2006.
    • N. Andriolli, H. Harai, J. Buron, S. Ruepp, and P. Castoldi, "Wavelength Assignment Schemes for Connection-oriented OPS Networks", ONDM 2006, Kgs. Lyngby, Denmark, May 2006.

 

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This page was last updated on December 17, 2009 by Lars Staalhagen (lars.staalhagen@fotonik.dtu.dk)