Teleprotection signalling over an IP/MPLS network

Protection of electricity networks have developed to incorporate communications, referred to as protection signalling. Due to the evolution of the electricity supply system, there are many developments pending within the scope of protection signalling and protection engineering in general. This project investigates the use of current and emerging communications technologies (i.e. packetised networks) being applied and incorporated into current protection signalling schemes and technologies. The purpose of the project is to provide a more cost-effective solution to protection schemes running obsolescent hardware. While the medium-term goal of the industry is to move entirely to IEC 61850 communications, legacy teleprotection relays using non-IP communications will still exist for many years to come. For companies to be ready for an IEC 61850 rollout a fully deployed IP/MPLS network will be necessary and it can be seen that various companies worldwide are readying themselves in this way. However, in the short-term for these companies, this means maintaining their existing TDM network (which runs current teleprotection schemes) and IP/MPLS network. This is a costly business outcome that can be minimised with the migration of services from and decommissioning of TDM networks. Network channel testing was the primary testing focus of the project. The testing proved that teleprotection traffic with correct QoS markings assured the system met latency and stability requirements. Furthermore, MPLS resiliency features (secondary LSPs & Fast-reroute) were tested and proved automatic path failover was possible under fault conditions at sub-30ms speeds

A survey on OFDM-based elastic core optical networking

Orthogonal frequency-division multiplexing (OFDM) is a modulation technology that has been widely adopted in many new and emerging broadband wireless and wireline communication systems. Due to its capability to transmit a high-speed data stream using multiple spectral-overlapped lower-speed subcarriers, OFDM technology offers superior advantages of high spectrum efficiency, robustness against inter-carrier and inter-symbol interference, adaptability to server channel conditions, etc. In recent years, there have been intensive studies on optical OFDM (O-OFDM) transmission technologies, and it is considered a promising technology for future ultra-high-speed optical transmission. Based on O-OFDM technology, a novel elastic optical network architecture with immense flexibility and scalability in spectrum allocation and data rate accommodation could be built to support diverse services and the rapid growth of Internet traffic in the future. In this paper, we present a comprehensive survey on OFDM-based elastic optical network technologies, including basic principles of OFDM, O-OFDM technologies, the architectures of OFDM-based elastic core optical networks, and related key enabling technologies. The main advantages and issues of OFDM-based elastic core optical networks that are under research are also discussed

Implementing Soak Testing for an Access Network Solution

Tietoliikennelaitteiden ohjelmistojen toiminnalle asetetaan erittäin kovat laatuvaatimukset. Operaattoreilla on yleensä asiakkaiden kanssa SLA sopimukset, joiden rikkomisesta operaattorit saattavat joutua maksamaan suuriakin korvauksia. Lisäksi jokainen hetki, jolloin laite ei ole toimintavalmis, tuottaa operaattorille kustannuksia menetettyjen tulojen muodossa. Tämän vuoksi on erittäin tärkeää, että laitteet ovat jatkuvasti toimintakunnossa eikä palvelukatkoksia tule. Tämän diplomityön tavoitteena oli kehittää automatisoitu pitkän ajan testausjärjestelmä IP/MPLS pohjaiselle Tellabs 8600 reititinperheelle. Testattava järjestelmä koostuu useista verkkoelementeistä sekä graafisesta Tellabs 8000 verkonhallintajärjestelmästä. Tämän testausympäristön tavoitteena on paljastaa ongelmia, jotka eivät tule esiin normaalissa toiminnallisessa tai regressiotestauksessa vaan vaativat ilmaantuakseen pidempää ajoaikaa tai useita toistoja. Työssä kehitettiin kehys sille, kuinka testausympäristössä voidaan suorittaa automaattisesti erilaisia operaatioita sekä voidaan ohjelmallisesti havaita mahdollisia ongelmatilanteita. Testausjärjestelmä toteutettiin onnistuneesti ja täyttää sille asetetut tavoitteet. Testausjärjestelmä on otettu käyttöön Tellabsin systeemitestauksessa ja on käyttöönoton jälkeen osoittautunut hyödylliseksi ja tehokkaaksi järjestelmäksi. Systeemitestauksen käyttöön toteutettiin myös toinen täysin identtinen ympäristö.The quality requirements are extremely demanding for telecommunications software. Operators usually have SLA agreements with their customers, and violations to that contract may lead to serious compensations. Furthermore, every moment that equipment or some service is not operating correctly means lost income for the operator. For these reasons, it is extremely important for a telecommunications equipment to continue functioning properly without service affecting breaks. The purpose of this thesis was to design and implement automated soak testing for the IP/MPLS-based Tellabs 8600 router series. The system under test is composed of several network elements and a graphical Tellabs 8000 Network Management System. The purpose of this testing environment is to reveal defects that do not show up immediately in functional or regression testing but may manifest when the system is used for longer periods or operations are executed many times. A framework for automatically operating the test network and detecting problems programmatically was implemented in this thesis. The testing environment was successfully implemented and satisfies the objectives initially set for it. Testing environment has been taken into use in system testing at Tellabs and after deployment has turned out to be useful and effective. Another identical environment was also implemented for the system testing group

Cross-layer modeling and optimization of next-generation internet networks

Scaling traditional telecommunication networks so that they are able to cope with the volume of future traffic demands and the stringent European Commission (EC) regulations on emissions would entail unaffordable investments. For this very reason, the design of an innovative ultra-high bandwidth power-efficient network architecture is nowadays a bold topic within the research community. So far, the independent evolution of network layers has resulted in isolated, and hence, far-from-optimal contributions, which have eventually led to the issues today's networks are facing such as inefficient energy strategy, limited network scalability and flexibility, reduced network manageability and increased overall network and customer services costs. Consequently, there is currently large consensus among network operators and the research community that cross-layer interaction and coordination is fundamental for the proper architectural design of next-generation Internet networks. This thesis actively contributes to the this goal by addressing the modeling, optimization and performance analysis of a set of potential technologies to be deployed in future cross-layer network architectures. By applying a transversal design approach (i.e., joint consideration of several network layers), we aim for achieving the maximization of the integration of the different network layers involved in each specific problem. To this end, Part I provides a comprehensive evaluation of optical transport networks (OTNs) based on layer 2 (L2) sub-wavelength switching (SWS) technologies, also taking into consideration the impact of physical layer impairments (PLIs) (L0 phenomena). Indeed, the recent and relevant advances in optical technologies have dramatically increased the impact that PLIs have on the optical signal quality, particularly in the context of SWS networks. Then, in Part II of the thesis, we present a set of case studies where it is shown that the application of operations research (OR) methodologies in the desing/planning stage of future cross-layer Internet network architectures leads to the successful joint optimization of key network performance indicators (KPIs) such as cost (i.e., CAPEX/OPEX), resources usage and energy consumption. OR can definitely play an important role by allowing network designers/architects to obtain good near-optimal solutions to real-sized problems within practical running times