OPNET University Program

University: Cork Institute of Technology
Name of sponsoring Professor: Dirk Pesch
Department: Electronic Engineering

The most prevalent choices of simulators for simulating a vehicular network in the research literature are OPNET and OMNET++. However, OPNET provides higher industrial standards and more network examples can be utilized. In an effort to develop a simulation test bed to facilitate short range, fast moving vehicle communications we propose to use OPNET, a paper has been submitted to IEEE ISWCS 06 and are awaiting peer review results.OPNET's MANET, WIRELESS and WLAN models are ideally suited for the new dedicated short distance communication (DSRC) algorithm and IEEE 802.11p protocol development.

We have already evaluated the performance of 802.11b networks in vehicular environments using OPNET discrete event simulations. Meanwhile, to make a comparison between real test and simulations, data from car-to-car and car-to-infrastructure communications were also measured in high-way and other road environments. The result we obtained using OPNET acts as a benchmark for our algorithm/protocol design.

Authored papers

1. Application Driven Routing For Vehicular Ad Hoc Networks ¨C A Necessity, The First Annual International Symposium on Vehicular Computing Systems, 2008

2. A Novel Reactive Routing Protocol for Applications in Vehicular Environments, the Eleventh Annual International Symposium on Wireless Personal Multimedia Communications, 2008

OPNET will be used to simulate a multi-hop wireless mesh network (WMN) in an in-building environment. WMN is presently an open research area as the problem of load balancing and optimal routing within the mesh still needs to be addressed. The main problem with multi-hop WMNs is proper load balancing and routing of data traffic. As data traffic is relayed by intermediate nodes on multi-hop routes towards a fixed internet connection, this leads to congestion and low overall network capacity. Therefore a more robust and fault tolerant routing architecture is needed. OPNET will be used to carryout simulations for the proposed self-organising and load balancing models that would be developed during the course of this research.

III. Title: Adapting Peer-to-Peer (P2P) Technologies for Mobile Ad-hoc Networks (MANETs)

Peer-to-Peer (P2P) traffic is a dominant source of Internet traffic contributing 60-80% of the traffic volume on ISP platforms in Europe and North America. Mobile Ad-hoc Networks (MANETs), a popular research area because of the self healing and self managing characteristics, share many of the same objectives as P2P networks and also fundamentally address the same problem: How to provide seamless connectivity and services in a dynamic and decentralised environment. As unstructured P2P solutions are not suitable for MANETs due to the increased network overhead and inefficient routing process, structured P2P solutions need to be employed. However as structured P2P solutions are typically designed for the wired Internet, modifications are required to cope with a highly dynamic and mobile environment, characteristic of MANETs. OPNET is the chosen simulation package as it provides higher industrial standards, a detailed MANET model and is a highly regarded simulation tool.

The aim of this research is to develop a large scale hierarchical cluster based MANET that will provide structured P2P services e.g. VoIP. It will involve the optimisation of structured P2P technologies e.g. Chord for highly mobile dynamic MANETs in the face of frequent link breakages, mobile nodes and resource constraints.

Cable television providers are actively moving towards a transition from their traditional core business of television channel provision to that of a full service provider for voice, video and data telecommunications. While there are competing standards, the data over cable service interface specification (DOCSIS) has been adopted as the major industry standard. OPNET is the simulation tool of choice as it provides a DOCSIS1.1 model that has been developed by OPNET in conjunction with the CableLabs' Bandwidth Modelling and Management Vendor Forum.

The aim of this research is to develop and evaluate broadband delivery over hybrid fibre coax (HFC) DOCSIS based networks. This research will involve the investigation of traffic management and scheduling algorithms (queuing, policing, and shaping) that looks towards improving the throughput performance in a fully loaded HFC network.

The first step in developing broadband delivery over HFC network was analyzing the existing OPNET DOCSIS model. The existing OPNET DOCSIS model is developed based on the DOCSIS1.1 specification. However, this model is not fully compliant with this specification. Our main requirement was to enhance the already existing DOCSIS model in OPNET, to a standard adequate to allow the implementation of channel bonding for the DOCSIS 3.0 specification. In order for this, the existing OPNET model had to be enhanced. The following items were emphasised as having a negative effect for the realisation of channel bonding for DOCSIS 3.0. Hence, they have been implemented to overcome any drawbacks.

The current OPNET model has the majority of its DOCSIS implementation contained in a CMTS DOCSIS finite state machine (FSM) and a CM DOCSIS FSM with a fixed setup for all CMs. As more features will be added to the OPNET DOCSIS model, the more complicated and cumbersome the system will become. Hence it was thought to be advantageous to modularise the single FSM to allow for a more accurate and structured environment.

The existing OPNET DOCSIS model only implements features of DOCSIS 1.1. Features such as multiple service flows and enhanced QoS were not modelled. Each CM was restricted to a single service flow. This structure does not match the actual CM/CMTS world very well. It increased the difficulty of modelling the new DOCSIS 3.0 protocols and decreased the relevance of the simulations. Hence multiple service flows were modelled on the DOCSIS 1.1 architecture to provide a more realistic model.

To enhance Quality of Service (QoS), Connection Admission Control (CAC) was implemented during the CM registration phase to assess bandwidth requirements for more efficient use of both US and DS bandwidths. Traffic shaping was also considered for enhanced QoS. Here two different traffic shaping algorithms were implemented so that more efficient utilisation of bandwidth would be incorporated

1. Downstream Channel Bonding for HFC Networks, IEEE Annual Broadcast Symposium, 2007.

2. Video Streaming over High Speed Cable Networks using an Adaptive ItswTCM, Broadband Europe, 2007.

4. Modelling Approaches to Multipband Service Delivery in DOCSIS 3.0 ¨C An architecture Perspective, Broadband Multimedia Symposium, 2007.

For building automation and control wireless sensor networks provide a low cost means of extending existing wired building management systems. Sensor networks rely on RF communication and while needing significantly reduced cabling effort, if any, they are provide easy device installation, network extension and reconfiguration. Wireless sensor networks are essential in providing flexible and adaptable deployments that can be used in conjunction with existing management systems. Key to effective sensor network operation are resource management and routing. For the purposes of this research OPNET will be used to develop a sensor network simulation platform the uses the IEEE802.15.4 MAC and physical layer interfaces. This platform will be used in the design, development and implementation of management and routing algorithms for responsive built environments.

VI. Title: A Design Methodology for Commissioning Indoor Wireless Sensor and Actuator Networks

The objective of this research work is to improve on the current methodologies for the design and commissioning of Wireless Sensor and Actuator Networks (WSAN) within indoor environments. As part of this research, Wi-Design, a WSAN Design Tool, will be used in conjunction with OPNET to design a WSAN architecture that meets the user and application requirements. Wi-Design can automatically determine the required number and positions of the different devices (sensors, actuators, routers and access points) for any indoor environments and with respect to sensing and actuation requirements. OPNET will be used to fine tune the choice of protocol stack and implementation parameters and to assess the lifetime and QoS of the final design. OPNET will be used to simulate IEEE 802.15.4 based WPAN, using ZigBee, 6LowPAN and possibly other protocols.

University: Cork Institute of Technology
Name of sponsoring Professor: Dr. Oliver Gough
Department: Electronic Engineering/Computing

This module is for senior level students taking the B.Sc in Software Development and Computer Networking. The module introduces the student to modeling and design principles for computer and telecommunication networks. Students learn about mathematical modeling techniques, mathematical and computer based design techniques and apply those to case studies of real network design problems.
OPNET is being used in the laboratory sessions to apply the design principles and techniques and enhance the visualization of network operations.