Spurred by change in government regulations and to leverage lower-cost technology and services, many land mobile radio (LMR) operators have begun transitioning from circuit-switched to packet-switched backbone networks to handle their future communication needs. Due to the unique demands of packet-switched backbone networks for LMR, it may not be wise to carry over the previously implemented security methods used with circuit-switch systems or to treat an LMR backbone as a regular packet-switched network. This thesis investigates security in packet-switched LMR backbone networks to identify security issues in packet-switched LMR networks and provide possible solutions for them. Security solutions that are examined include different types of virtual private networks (VPNs), various encryption and keying procedures for safe communication, and logic behind how and where to implement security functions within the network. Specific schemes examined include IP Security (IPSec), OpenVPN, Virtual Tunnel (VTun), and Zebedee. I also present a quantitative analysis of the effects that the solutions have on packet-switched networks, in terms of link utilization, and on voice traffic, in terms of delay and delay jitter. In addition, I evaluate, in general terms, the additional cost or complexity that is introduced by the different security solutions. Simulation with OPNET Modeler was used to evaluate how the various security schemes affect voice communication and network performance as a whole. Since OPNET Modeler does not provide models of security functions, the source code of the transceiver system models was modified to introduce additional overhead that is representative of the various security solutions. Through experimentation, simulation, and analysis of the security schemes considered, it was found that the most effective security scheme overall for a packet-switched LMR backbone network would either be IPSec or OpenVPN implemented at the base stations and end-hosts. Both security schemes provide strong encryption, flexibility, and are actively supported. However, if bandwidth is scarce and flexibility is less important, then a security solution with less overhead, such as VTun, should be considered. Thus, one has to balance performance with security to choose the most effective security solution for a particular application. / Master of Science

Given the current developments and advances in the scientific and technological aspects of human knowledge and introducing new approaches in various fields of telecommunication technologies and industries, there has been an increasing growth in its players' plans and a positive change in their outlooks in order to achieve the target of "anywhere and anytime access". Recent developments of WiMAX (Worldwide interoperability for Microwave Access) networks, as a sign of increasing needs and demands for new telecommunication services and capabilities, have led to revolutions in global telecommunication which should be perceived properly in terms of the commercial and technical aspects in order to enjoy the new opportunities. Most experts believe that WiMAX technology is a preliminary step to develop Fourth Generation networks known as 4G technologies. It has not only succeeded in the utilization of several of the latest telecommunication techniques in the form of unique practical standards, but also paved the way for the quantitative and qualitative developments of high-speed broadband access. IEEE 802.16 Standard introduces several advantages, and one of them is the support for Quality of Services (QoS) at the Media Access Control (MAC) level. For these purposes, the standard defines several scheduling classes at MAC layer to treat service flow in a different way, depending on QoS requirements. In this thesis, we have proposed a new QoS framework for Point-to-Multi Point (PMP) 802.16 systems operating in Time Division Duplexing (TDD) mode over a WirelessMAN-OFDM physical layer. The proposed framework consists of a Call Admission Control (CAC) module and a scheduling scheme for the uplink traffic as well as a simple frame allocation scheme. The proposed CAC module interacts with the uplink scheduler status and it makes its decision based on the scheduler queue status; on the other hand, the proposed scheduling scheme for the uplink traffic aims to support realtime flows and adapts the frame-by-frame allocations to the current needs of the connections, with respect to the grants boundaries fixed by the CAC module. Extensive OPNET simulation demonstrates the effectiveness of the proposed architecture.

Approved for public release, distribution is unlimited / In this thesis, the scalability issues of Simple Network Management Protocol (SNMP) in optical network management are explored. It is important to understand the effect of varying the number of nodes, the request inter-arrival times and the polling interval on the performance of SNMP and number of nodes that can be effectively managed. The current study explored the effect of varying these parameters in a controlled test environment using the OPNET simulation package. In addition, traffic analysis was performed on measured SNMP traffic and statistics were developed from the traffic analysis. With this understanding of SNMP traffic, an SNMPv1 model was defined and integrated into an OPNET network model to study the performance of SNMP. The simulation results obtained were useful in providing needed insight into the allowable number of nodes an optical network management system can effectively manage. / Civilian, Singapore Ministry of Defense

The aim of this thesis is to investigate the traffic patterns in the mobile data networks. In this work, a simple Cellular Digital Packet Data (CDPD) network was modeled in order to be used in simulations. For the purpose of using in the CDPD model, a synthetic bursty traffic model was produced and using different traffic patterns some performance investigations were made in CDPD network. During the whole work, OPNET simulation tool was used. The CDPD network modeled by OPNET simulation tool was compared with a CDPD model described in the literature and the differences were shown. The new model has some new features: 1) Burst transmission of MAC blocks. 2) Exponential backoff. 3) New packet structures. 4) Frame segmentation and encapsulation into MAC layer frames. Using OPNET, a traffic having higher level of burstiness was produced and applied to the CDPD network model. Under the bursty traffic, some CDPD performance parameters were collected and according to the collected results some suggestions were given.

Ο όρος ‘Δίκτυα Επόμενης Γενιάς’ αναφέρεται σε μελλοντικά δίκτυα πρωτοποριακής λογικής και δομής, προσανατολισμένα στην υποστήριξη σύγχρονων απαιτητικών εφαρμογών και στη βελτίωση της λειτουργικότητας της τερματικής συσκευής, όπως την αντιλαμβάνεται ο χρήστης. Πολύ σημαντικά στοιχεία της νέας τηλεπικοινωνιακής πραγματικότητας που επιφέρουν τα δίκτυα αυτά, και με τα οποία σχετίζεται άμεσα η παρούσα εργασία, είναι η διάθεση προώθησης της γενικευμένης κινητικότητας των ασύρματων χρηστών και η ενθάρρυνση της σύγκλισης επιμέρους τεχνολογιών διαφορετικών δικτύων και της δημιουργίας υβριδικών ετερογενών δικτύων, με στόχο την επίτευξη καλύτερης αξιοποίησης του φάσματος και βελτίωσης των ρυθμών μετάδοσης δεδομένων. Σκοπός της παρούσας διπλωματικής εργασίας είναι η παρουσίαση της δομής και των λειτουργιών των Δικτύων Επόμενης Γενιάς, καθώς και ορισμένων υπαρχόντων τύπων ασύρματων δικτύων, η συνεργασία των οποίων θα μπορούσε να προσφέρει τα επιθυμητά πλεονεκτήματα. Δύο τέτοια είδη δικτύων είναι το δίκτυο κινητής τηλεφωνίας UMTS και τα τοπικά δίκτυα τεχνολογίας WLAN, τα οποία εξετάζονται ενδελεχώς ως προς τα χαρακτηριστικά τους και, κυρίως, ως προς τους μηχανισμούς διευθέτησης της περιαγωγής των χρηστών. Περιλαμβάνεται επίσης μία περιγραφή της λειτουργίας του Mobile IP, πρωτοκόλλου που θεωρείται ιδιαίτερα χρήσιμο για τη διαχείριση της κινητικότητας χρηστών ανάμεσα σε περιοχές εξυπηρέτησης διαφορετικών δικτύων. Η εργασία καταλήγει στη μοντελοποίηση των παραπάνω συστημάτων σε περιβάλλον εξομοίωσης, επιδιώκοντας την αξιολόγηση της αποτελεσματικότητας του ενδεχόμενου συνδυασμού των συστημάτων UMTS και WLAN και της χρησιμότητας του Mobile IP. Το λογισμικό που χρησιμοποιείται γι’ αυτόν το σκοπό είναι το OPNET Modeler ®, ένα πρόγραμμα που αναδεικνύεται τα τελευταία χρόνια σε εργαλείο όλο και περισσότερο πολύτιμο, τόσο σε ερευνητικό όσο και σε επιχειρησιακό επίπεδο. / The term ‘Next Generation Networks’ refers to future networks of revolutionary concept and structure, oriented to the support of demanding applications and the upgrade of the terminal device’s functionality, as perceived by the user. Some very important aspects of the new telecommunications reality that is brought on by these networks, and to which this project is directly related, is the intention of promoting generalized mobility for the wireless users and the encouragement of the convergence of distinct network technologies and of the foundation of new hybrid heterogeneous networks, in order to achieve better spectrum utilization and improvement of data transmission rates. The purpose of the current diploma thesis project is to present the structure and the functions of the Next Generation Networks, as well as of some existing types of wireless networks, the cooperation of which could provide the desirable advantages. Two such network types are the UMTS mobile telephony network and the local networks of WLAN technology, that are examined thoroughly towards their characteristics and, foremost, towards their roaming arrangement mechanisms. Also included is a description of the operation of Mobile IP, a protocol that is considered particularly convenient for the management of users’ mobility between service areas of different networks. The project concludes to the modeling of the above mentioned systems in a simulation environment, aiming to evaluate the efficiency of the prospective combination of the UMTS and WLAN systems and the utility of Mobile IP. The software used for this purpose is OPNET Modeler ®, a program that has emerged during the last years as an increasingly valuable research and business tool.

Multiprotocol Label Switching (MPLS) is an emerging technology which ensures the reliable delivery of the Internet services with high transmission speed and lower delays. The key feature of MPLS is its Traffic Engineering (TE), which is used for effectively managing the networks for efficient utilization of network resources. Due to lower network delay, efficient forwarding mechanism, scalability and predictable performance of the services provided by MPLS technology makes it more suitable for implementing real-time applications such as voice and video. In this thesis performance of Voice over Internet Protocol (VoIP) application is compared between MPLS network and conventional Internet Protocol (IP) network. OPNET modeler 14.5 is used to simulate the both networks and the comparison is made based on some performance metrics such as voice jitter, voice packet end-to-end delay, voice delay variation, voice packet sent and received. The simulation results are analyzed and it shows that MPLS based solution provides better performance in implementing the VoIP application. In this thesis, by using voice packet end-to-end delay performance metric an approach is made to estimate the minimum number of VoIP calls that can be maintained, in MPLS and conventional IP networks with acceptable quality. This approach can help the network operators or designers to determine the number of VoIP calls that can be maintained for a given network by imitating the real network on the OPNET simulator. / 0046737675303

Enormous developing electronic technology has brought telecommunication to the sky inspiring popularity. Wireless Network (WN) technology will be emerging so far human. Presently users give the impression loving be connected all the time (everywhere) to the network or Internet through diverse access system, e.g., Universal Mobile Telecommunications System, Mobile Ad-hoc Network (MANET) [9] and Worldwide Interoperability for Microwave Access [30]. In telecommunication; MANET is considered as self-configured unlike nodes creating infrastructure-less network connected by means of WN, as nodes can exchange data packets without a central control [18]. Choosing beyond line of sight (BLOS) communication, MANET can be an intelligent selection, which is flexible for using and cost saving. However, to maintain quality of service (QoS), more or less challenges still have to be resolved [18]. Multimedia as well as VoIP (Voice over Internet Protocol) gaining more popularity as the internet world favored by the huge use of WN (access technologies) [20]. To maintain persistent services in different MANET situation unlike routing protocols (RP) are employed. In this thesis known (MANET) routing protocols OLSR (Optimized Link State Routing) [20], DSR (Dynamic Source Routing) [30] and TORA (Temporally Ordered Routing Algorithm) [14] have been considered for voice traffic as they maintaining dissimilar characteristics in the dissimilar situations as WN factors (like; bandwidth, signal strength, network traffic or load, network size) influencing the voice quality [9]. This thesis work focusing on the impact of node mobility influencing voice quality in unlike RPs in MANET. To decide the best suit RP in the MANET, the OPNET (Optimized Network Engineering Tool) Simulator 16.0 has been brought into play. OLSR is proposed to be best fitting RP for MANETs running VoIP appliance. / Enorma utveckla elektroniska tekniken har fört telekommunikation till himlen inspirerande popularitet. Trådlöst nätverk (WN) teknik kommer att utvecklas så långt mänsklig. För närvarande användare ger intryck kärleksfulla vara ansluten hela tiden (överallt) till nätverket eller Internet via olika system för tillträde, till exempel, Universal Mobile Telecommunications System, Mobil Ad-hoc-nätverk (Manet) [9] och Worldwide Interoperability för Microwave Access-[30 ]. I telekommunikation, är Manet betraktas som själv-konfigurerade skillnad noder skapa infrastruktur mindre nätverk som är anslutet via WN, som noder kan utbyta datapaket utan central styrning [18]. Välja bortom synfältet (Blos) kommunikation, kan Manet vara ett intelligent val, som är flexibel för att använda och kostnadsbesparande. Men för att upprätthålla service (QoS), mer eller mindre problem återstår att lösas [18]. Multimedia samt VoIP (Voice over Internet Protocol) allt mer populärt eftersom internet världen gynnas av den enorma användningen av WN (accesstekniker) [20]. För att behålla ihållande tjänster i olika Manet situationen skillnad routing protokoll (RP) är anställda. I denna kända avhandling (Manet) routingprotokoll OLSR (Optimerad Routing Link State) [20], DSR (Dynamic Source Routing) [30] och Tora (Tidsmässigt ordnad routing algoritm) har [14] ansetts för taltrafik som de upprätthålla olika egenskaper i olika situationer som WN faktorer (som, bandbredd, signalstyrka, nätverkstrafik eller last, nätverkets storlek) Att påverka ljudkvaliteten [9]. Detta examensarbete fokuserar på effekterna av nod rörlighet påverka röstkvalitet i motsats till RPS i Manet. För att avgöra det bäst passar RP i Manet, den OPNET (Optimerad Network Engineering Tool) Simulator 16,0 har kommit in i bilden. OLSR föreslås bli bäst passar RP för MANETs köra VoIP-apparaten. / Bergvägen 18 5tr 196 31 Kungsängen Sweden Mob: 0046(0)737106987

The aim of my diploma is to introduce the SNMP protocol designed for remote device management to the readers and present its implementation into the Opnet Modeler simulation environment. For the implementation the DiffServMIB database has been chosen, which describes the components of differentiated services mechanism. My diploma thesis describes in detail the possibilities of application of the DiffServMIB database in traffic management. The design of a simulation model, which represents the differentiated data processing in input and output direction on a router interface, is also introduced. Next, this model is implemented into the Opnet Modeler simulation environment. The goal of this simulation model is the possibility of simple configuration of individual MIB attributes. In my work I also suggest an implementation method able to interconnect the MIB database with the configuration process of the active network element - with focus on output procedures of DiffServ mechanism.

The Master´s thesis deals with the field of converged networks and their effective utilization, focusing specifically on telematic networks. For modelling of a specific application, the field of vehicle telematics has been chosen. The thesis consists of two series of simulations performed in Opnet Modeler network simulator. The first theoretic part gave an overview of protocols used in converged networks, with a more detailed description of routing protocols. The attention also centred on the mechanisms for assuring the quality of service in IP. The subsequent practical part consisted in creating the simulation of a converged telematic network in Opnet Modeler network simulator, configuration of scenarios for assuring QoS using RSVP and DSCP protocols and the simulation itself. The results of the simulations for both scenarios were compared and represented in graphic form. The second theoretic part described queueing disciplines, as well as congestion control and congestion avoidance mechanisms. The corresponding practical part compared FIFO, PQ and WFQ queueing algorithms within the same simulated converged telematic network, using DSCP protocol scenario, which gave much better results in the first series of simulations. Again, the results of the simulations were compared and represented in graphic form.

The main aim of this thesis is to familiarize with options of services using real-time data transfer in wireless networks. Theoretical part presents wireless network based on IEEE 802.11 standard and its practical use. Large part is focuses on 802.11e standart, that provides support for quality of service in wireless networks. Furthemore this thesis deals with transport and applicaton protocols supporting multimedia streaming over computer network. Second chapter is focused on analyzing real computer network with purpose in measuring parametrs influencing quality of service such as bandwith, delay, jitter and loss. Last part deals with the design of wireless network in OPNET Modeler enviroment with focus on simulating parameters that influence quality of service.