Next generation networks will provide customers with a service mix placing variable demands for resources on the underlying infrastructure, motivating automated telecommunications services management approaches. This thesis proposes the Autonomic Service Architecture (ASA) for automated service delivery over next generation networks. First, we propose an architectural blueprint for ASA. We describe our view of the next generation network infrastructure, which will be application oriented. We elaborate on the layered design of ASA, the virtualization of resources, and the separation between manual and autonomic functions in the service delivery lifecycle. The autonomic functions are delivered by the interaction between Autonomic Resource Brokers (ARBs). The architecture of an ARB is then detailed, with a description of its different components and the message exchanges needed. Next, we discuss a Peer-to-Peer (P2P) naming and mobility management approach for next generation networks using ASA. This P2P approach will help ensure the scalability, robustness, and flexibility that ASA needs to ensure service delivery over next generation networks. The proposed P2P naming and mobility management infrastructure is then detailed, and its performance is evaluated. Finally, we suggest several autonomic resource management algorithms for ASA. The first algorithm is based on the Transportation Model, commonly used in the Operations Research community for cost minimization in delivering a commodity from sources to destinations, adapted to perform allocation of virtual resources. The second algorithm is based on the Assignment Model, commonly used in the Operations Research community for cost minimization in assigning several jobs to several workers, adapted to perform autonomic assignment of dedicated virtual resources. The third algorithm is based on Inventory Control, commonly used in the Operations Research community to analyze inventory systems, placing and receiving orders when needed for a given product, adapted to predict the demand on virtual resources. The fourth algorithm is based on Reinforcement Learning, commonly used in the Machine Learning community by agents to find a control policy that will maximize the observed rewards over their lifetime, adapted to adjust the prices of virtual resources.

Next generation networks will provide customers with a service mix placing variable demands for resources on the underlying infrastructure, motivating automated telecommunications services management approaches. This thesis proposes the Autonomic Service Architecture (ASA) for automated service delivery over next generation networks. First, we propose an architectural blueprint for ASA. We describe our view of the next generation network infrastructure, which will be application oriented. We elaborate on the layered design of ASA, the virtualization of resources, and the separation between manual and autonomic functions in the service delivery lifecycle. The autonomic functions are delivered by the interaction between Autonomic Resource Brokers (ARBs). The architecture of an ARB is then detailed, with a description of its different components and the message exchanges needed. Next, we discuss a Peer-to-Peer (P2P) naming and mobility management approach for next generation networks using ASA. This P2P approach will help ensure the scalability, robustness, and flexibility that ASA needs to ensure service delivery over next generation networks. The proposed P2P naming and mobility management infrastructure is then detailed, and its performance is evaluated. Finally, we suggest several autonomic resource management algorithms for ASA. The first algorithm is based on the Transportation Model, commonly used in the Operations Research community for cost minimization in delivering a commodity from sources to destinations, adapted to perform allocation of virtual resources. The second algorithm is based on the Assignment Model, commonly used in the Operations Research community for cost minimization in assigning several jobs to several workers, adapted to perform autonomic assignment of dedicated virtual resources. The third algorithm is based on Inventory Control, commonly used in the Operations Research community to analyze inventory systems, placing and receiving orders when needed for a given product, adapted to predict the demand on virtual resources. The fourth algorithm is based on Reinforcement Learning, commonly used in the Machine Learning community by agents to find a control policy that will maximize the observed rewards over their lifetime, adapted to adjust the prices of virtual resources.

The Orthogonal Frequency Division Multiplexing is a promising technology for the Next Generation Networks. This technique was selected because of the flexibility for the various parameters, high spectral efficiency, and immunity to ISI. The OFDM technique suffers from significant digital signal processing, especially inside the Inverse/ Fast Fourier Transform IFFT/FFT. This part is used to perform the orthogonality/De-orthogonality between the subcarriers which the important part of the OFDM system. Therefore, it is important to understand the parameter effects on the increase or to decrease the FPGA power consumption for the IFFT/FFT. This thesis is focusing on the FPGA power consumption of the IFFT/FFT uses in the OFDM system. This research finds a various parameters effect on FPGA power of the IFFT/FFT. In addition, investigate the computer software used to measure and analyse the FPGA power consumption of OFDM transceivers, and selects the target hardware used in the computer software. The researched parameters include the number of bits used in calculating the phase factor precision; Cyclic Prefix length effected on IP core IFFT, Subcarrier modulation type, word length width, Real and Complex Value IFFT, IFFT length, and subcarriers sampling frequency. The real value IFFT is proposed in 1987 and implemented in this thesis. These parameters above are discussed by comparing the result between the Real and Complex value IFFT used inside the OFDM system.

Το περιεχόμενο του συγκράματος ασχολείται με τη μελέτη αρχιτεκτονικών διαστρωμάτωσης για τη διερεύνηση των λειτουργικών απαιτήσεων των ασύρματων δικτύων επόμενης γενιάς. Αφού γίνει η μελέτη των τεχνικών καταχώρισης συχνοτήτων στα κυτταρικά συστήματα των κινητών επικοινωνιών κατόπιν αναλύονται οι λειτουργικές διαδικασίες των κυτταρικών συστημάτων κινητής τηλεφωνίας όπως και το μοντέλο καταχώρισης ραδιοπόρων το οποίο βασίζεται στις τεχνικές Erlang. Ακολούθως προτείνονται μέσω μαθηματικής ανάλυσης διεπίπεδες τεχνικές μεταγωγής. Εν συνεχεία, παρουσιάζεται η εφαρμογή της πολυεπίπεδης αρχιτεκτονικής στα σύγχρονα κυτταρικά συστήματα όπου αναλύεται η αρχιτεκτονική UMTS/HAP. Στα αποτελέσματα της προσομοίωσης που κάνουμε στο σύστημα μας, παρατηρούμε την αισθητή μείωση της dropping/blocking πιθανότητας όταν εφαρμοστεί η προτεινόμενη τεχνική. / The subject of diploma is about studying architectures of multilayrer in next generation wireless networks. After we study registration techniques in cellar systems of wireless communication systems, we analyze operating processes of mobile network and sources registration based on Erlang's techniques. after all, it is presented the application of multilayer architecture in modern cell systems where architecture UNTS/HAP is analyzed. In the results of our simulation we see that the blocking/dropping probability is decreased when out technique is enabled

Next Generation Networks (NGNs) aim to provide a unified network infrastructure to offer multimedia data and telecommunication services through IP convergence. NGNs utilize multiple broadband, QoS-enabled transport technologies, creating a converged packet-switched network infrastructure, where service-related functions are separated from the transport functions. This requires significant changes in the way how networks are managed to handle the complexity and heterogeneity of NGNs. This thesis proposes a Service Oriented Architecture (SOA) based management framework that integrates heterogeneous management systems in a loose coupling manner. The key benefit of the proposed management architecture is the reduction of the complexity through service and data integration. A network management middleware layer that merges low level management functionality with higher level management operations to resolve the problem of heterogeneity was proposed. A prototype was implemented using Web Services and a testbed was developed using trouble ticket systems as the management application to demonstrate the functionality of the proposed framework. Test results show the correcting functioning of the system. It also concludes that the proposed framework fulfils the principles behind the SOA philosophy.

La tesi è strutturata in 3 capitoli e analizza gli investimenti e la regolamentazione nel broadband market". Il primo capitolo analizza la letteratura teorica ed empirica sul rapporto tra gli investimenti e la regolamentazione nel settore delle telecomunicazioni. Il secondo capitolo fornisce un'analisi teorica sullo "stepping-stone theory". La terza parte fornisce un'analisi sull'impatto dei diversi regimi normativi per la costruzione della Next Generation Networks. / This dissertation is composed of three papers and discusses the issue of investment and regulation in broadband market. The first paper reviews the specialized but growing branch of the literature. It surveys the relevant theoretical and empirical literature on the relationship between regulation, at both retail and wholesale level, and investment in telecoms infrastructures. Theoretical analyses state that with respect to retail (incentive) regulation, the firm‘s incentive to invest is related to the level of price cap. As for access regulation, mandatory unbundling can possibly discourage firms‘ incentive to invest, but this is not the case for all circumstances because some studies have displayed an opposite (positive) effect on investment. The influence of regulators‘ limited ability to make credible commitment ex ante is not negligible either. Evidence in empirical findings exhibits a certain disunity. The majority concludes that local loop unbundling based on forward-looking cost methodology discourages both ILECs and CLECs from investing in networks, so that the stepping-stone theory is possibly not supported by the data; other findings support the non-negative effect of access regulation on investment. The second paper provides theoretical analysis on the stepping-stone theory. We dynamically model the competition between a vertically-integrated incumbent firm and a facilities-free new entrant in broadband market, where both firms are entitled with investment options: not only can the incumbent decide how much to spend in upgrading its existing network, but also the entrant can choose whether and when to invest on the construction of its own network. The analysis is conducted under three different kinds of competition: pure services-based, pure facilities-based and mixed competition. We find that the entrant's ability to provide value-added services affects the incumbent's investment choice. Our simulation results support the stepping-stone theory that access regulation provides an impetus for the entrant to invest in their own facilities after entering the market based on leased lines. It is also socially desirable because both the overall welfare and the consumer surplus are maximized in a regulated market under mixed competition. The third paper studies impacts of different regulatory regimes on the construction of Next Generation Networks (NGNs). We model the competition between a vertically-integrated incumbent firm and a facilities-free entrant firm in broadband market, where the incumbent has an investment option to upgrade its current network to the NGN. In order to analyze how policy settings affect the incumbent firm‘s investment choice, three kinds of regulatory regimes are discussed: no regulation, partial regulation (only the traditional network is regulated and the NGN is unregulated) and full regulation (both the traditional network and the NGN are regulated). We find that not only the entrant‘s ability to provide value-added services, but also the substitution factor that indexes the decrease in consumers‘ willingness to pay for the traditional service once the investment occurs, affect the incumbent‘s investment choice. Moreover, the comparison of results under different regimes shows that the incumbent invests the most under partial regulation, which sheds some light on impelling the deployment of Next Generation Networks.

Η διπλωματική ασχολείται με τα ετερογενή δίκτυα επόμενης γενιάς και με τα πρωτόκολλα ασφαλείας. Μελέτησα το σύνολο πρωτοκόλλων ΑΑΑ, τα οποία εξασφαλίζουν την πιστοποίηση, εξουσιοδότηση και τη λογιστική χρέωση, όπως παρατηρείται στα σύγχρονα δίκτυα. Κατόπιν, μελέτησα το σύστημα IMS, το οποίο εννοποιεί ασύρματα και σταθέρά δίκτυα μεταξύ τους, χρησιμιοποιώντας κοινά πρωτόκολλα που χρησιμοποιούνται στο μοντέλο TCP/IP (Internet). Τέλος, καταγράφονται συνηθισμένες επιθέσεις στην αρχιτεκτονική του IMS, με και χωρίς τη χρήση του SBC, που αποτελεί μία μονάδα ενίσχυσης ασφαλείας. / This project studies the heterogenous, next generation's networks and the security protocols that they use. The protocols AAA, which ensure the correct and safe authentication, authorization and accounting in these networks, have been studied. Thenwhile, I studied the IMS system, which unites wireless and wired networks, using comon protocols that are used in TCP/IP model(Internet). Finally, I present the results of a group of comon threats, with and without the use of the unit SBC, which is a unit that amplify the system's security.

Το αντικείμενο αυτής της διπλωματικής εργασίας είναι η μελέτη της δομής υπηρεσιών πάνω στα 0ίκτυα Επόμενης Γενιάς (Next Generation Networks, NGN). Συγκεκριμένα, περιγράφεται η αρχιτεκτονική IMS (IP Multimedia Subsystem) πάνω στην οποία βασίζεται η δομή των 0ικτύων Επόμενης Γενιάς. Στα πλαίσια της παρούσας διπλωματικής εργασίας γίνεται αρχικά μια σύντομη αναφορά στο ιστορικό δημιουργίας του IMS, ενώ στην συνέχεια γίνεται μια εκτεταμένη περιγραφή του μοντέλου και του τρόπου λειτουργίας του IMS. Συγκεκριμένα, αναλύονται οι οντότητες και τα σημεία αναφοράς από τα οποία αποτελείται το IMS καθώς και τα πρωτόκολλα που χρησιμοποιεί. Στη συνέχεια γίνεται μία αναφορά στην ασφάλεια του IMS, όπου αναφέρονται πιθανοί κίνδυνοι και απειλές για το IMS καθώς και τρόποι αντιμετώπισής τους. Έπειτα, παρουσιάζονται και περιγράφονται αναλυτικά οι υπηρεσίες που μπορεί να προσφέρει το IMS στα πλαίσια των 0ικτύων Επόμενης Γενιάς. Τέλος, γίνεται παρουσίαση ενός παραδείγματος εφαρμογής της υπηρεσίας VoIP πάνω από την IMS αρχιτεκτονική. Για την υλοποίηση αυτού του παραδείγματος χρησιμοποιήθηκε το πρόγραμμα προσομοίωσης OPNET 10.0, ενώ συλλέχθηκαν αποτελέσματα σχετικά με τη συμπεριφορά του πρωτοκόλλου SIP και της υπηρεσίας VoIP σε IMS περιβάλλον. / The objective of this diploma thesis is the study of the service structure of Next Generation Networks (NGN). Especially, the IMS architecture (IP Multimedia Subsystem) is being described, which the NGN structure is based on. Initially, there is a quick reference to the history of the development of IMS, and continually an extensive description is being made about the model and the functional mode of IMS. Next, security aspects of IMS are being described, and continually there is a presentation about the services that IMS offers. Finally, an example is being presented regarding the application of VoIP service using the IMS architecture. For the configuration of this example, the simulation program OPNET 10.0 was used, while results were collected regarding the behavior of SIP protocol and VoIP service in the IMS environment.

Το αντικείμενο της παρούσας διπλωματικής εργασίας είναι η μελέτη της αρχιτεκτονικής των Δικτύων Νέας Γενιάς (Next Generation Networks-NGN) με εστίαση στους μηχανισμούς του Επιπέδου Μετάδοσης και τις Λειτουργίες Τελικού Χρήστη. Συγκεκριμένα, περιγράφεται η αρχιτεκτονική IMS (IP Multimedia Subsystem) με τις αντίστοιχες λειτουργικές συνιστώσες και διεπαφές, ενώ στη συνέχεια παρατίθενται τα βήματα μετάβασης προς δίκτυα και προσβάσεις νέας γενιάς επιλεγμένων μεγάλων τηλεπικοινωνιακών Οργανισμών. Ακολούθως, γίνεται μια συνοπτική αναφορά στις λειτουργίες του επιπέδου μετάδοσης, ελέγχου μεταφοράς και διαχείρισης δικτύου και στη συνέχεια περιγράφεται λεπτομερώς η λειτουργική αρχιτεκτονική των κύριων λειτουργικών οντοτήτων του επιπέδου μετάδοσης (λειτουργίες ελέγχου προσάρτησης δικτύου-NACF, λειτουργίες ελέγχου διαχείρισης φορητότητας-MMCF, λειτουργίες ελέγχου πόρων –RACF, λειτουργίες μετάδοσης κορμού) και τα μοντέλα πληροφόρησης (ένδειξη δέσμευσης, πληροφορία απόκρισης πόρων μετάδοσης κ.α.) των επιμέρους στοιχείων των προαναφερθέντων δομικών οντοτήτων. Σε κάθε δομικό μοντέλο πληροφόρησης υπάρχει αναλυτική παρουσίαση των σημείων αναφοράς και ροών πληροφορίας που εμπλέκονται στη διαχείριση και έλεγχο φορητότητας, προσάρτησης δικτύου, διεργασίας μετάδοσης κορμού και πρόσβασης, αντιστοίχως. Στη συνέχεια, αναλύονται οι λειτουργίες τελικού χρήστη με ειδικότερη αναφορά στις λειτουργίες πύλης δικτύου (CPN) με τα επιμέρους λειτουργικά στοιχεία της, και τα δίκτυα που θα αποτελέσουν τον κορμό πάνω στον οποίο θα στηριχθεί η υλοποίηση της πρόσβασης των δικτύων νέας γενιάς. Πιο συγκεκριμένα, περιγράφονται οι τεχνολογίες πρόσβασης DSL (ADSL, ADSL2 και VDSL2) με τους υποκείμενους περιορισμούς του ρυθμού μετάδοσης (διαφωνία, εξασθένηση), Ethernet (EPON, P2P πάνω από χαλκό και οπτική ίνα), και PON (διασύνδεση P2MP με οπτικό διαμεριστή οπτικής ισχύος, GPON). Τέλος, αναλύονται οι καλωδιακές υποδομές που απαιτούνται για την ανάπτυξη των προσβάσεων νέας γενιάς (εύρος, διάρθρωση, πυκνότητα οπτικών ινών). / The theme of this particular thesis is the study of the Next Generation Networks –NGN architecture focusing on the functionalities of the Transport Stratum and the End User Functions. Specifically, it is described the IMS architecture (IP Multimedia Subsystem) and the related functional components, and then, it is listed the transition steps towards the next generation networks and access of selected Telecommunications Providers. Following, it is briefly outlined the functionalities of transport level, transport control and network management, as well, and subsequently, the functional architecture of the main entities of transport level (network attachment control functions –NACF, Mobility Management and Control Functions- MMCF, Resource and Admission Control Functions- RACF, Transport processing entities) and the information models (event registration reply, resource selection information reply etc) of the aforementioned functional components are being described, in detail. Each structural component is analytically presented with its reference points and information flows that are involved in the management as well as the control of mobility, network admission, transport core and access processing, respectively. Additionally, the end user functions are described, giving weighted reference to the customer premises gateway functions (CGF) and their individual entities, and the networks that will compose the core upon which the implementation of next generation access will be established. That is, different access types are presented such as DSL network (ADSL, ADSL2, VDSL2) with its transfer rate restrictions (i.e. attenuation), Ethernet network (EPON, P2P over copper and optical fiber) and PON (P2MP interconnection using optical power splitter ,GPON). Finally, it is analyzed the cable infrastructure needed for the development of the new generation access (optical fiber rate, structure, density).

Telephony plays a fundamental role in our society. It enables remote parties to interact and express themselves over great distances. The telephone as a means of communicating has become part of every day life. Organisations and industry are now looking at Voice over IP (VoIP) technologies. They want to take advantage of new and previously unavailable voice services. Various interested parties are seeking to leverage the emerging VoIP technology for more flexible and efficient communication between staff, clients and partners. <o>VoIP is a recent innovation enabled by Next Generation Network (NGN). It provides and enables means of communication over a digital network, specifically the Internet. VoIP is gaining wide spread adoption and will ultimately replace traditional telephony. The result of this trend is a ubiquitous, global and digital communication infrastructure. VoIP, however, still faces many challenges. It is not yet as reliable and dependable as the current Public Switched Telephone Network (PSTN). The employed communication protocols are immature with many security flaws and weaknesses. Session Initiation Protocol (SIP), a popular VoIP protocol does not sufficiently protect a users privacy. A user’s information is neither encrypted nor secured when calling a remote party. There is a lack of control over the information included in the SIP messages. Our specific concern is that private and sensitive information is exchanged over the public internet. This dissertation concerns itself with the communication path chosen by SIP when establishing a session with a remote party. In SIP, VoIP calls are established over unknown and untrusted intermediaries to reach the desired party. We analyse the SIP headers to determine the information leakage at each chosen intermediary. Our concerns for possible breach of privacy when using SIP were confirmed by the findings. A user’s privacy can be compromised through the extraction of explicit private details reflected in SIP headers. It is further possible to profile the user and determine communication habits from implicit time, location and device information. Our research proposes enhancements to SIP. Each intermediary must digitally sign over the SIP headers ensuring the communication path was not be altered. These signatures are added sequentially creating a chain of certified intermediaries. Our enhancements to SIP do not seek to encrypt the headers, but to use these intermediary signatures to reduce the risk of information leakage. We created a model of our proposed enhancements for attaching signatures at each intermediary. The model also provides a means of identifying unknown or malicious intermediaries prior to establishing a SIP session. Finally, the model was specified in Z notation. The Z specification language was well suited to accurately and precisely represent our model. This formal notation was adopted to specify the types, states and model behaviour. The specification was validated using the Z type-checker ZTC. Copyright / Dissertation (MSc)--University of Pretoria, 2010. / Computer Science / unrestricted