Ethernet - a survey on its fields of application

During the last decades, Ethernet progressively became the most widely used local area networking (LAN) technology. Apart from LAN installations, Ethernet became also attractive for many other fields of application, ranging from industry to avionics, telecommunication, and multimedia. The expanded application of this technology is mainly due to its significant assets like reduced cost, backward-compatibility, flexibility, and expandability. However, this new trend raises some problems concerning the services of the protocol and the requirements for each application. Therefore, specific adaptations prove essential to integrate this communication technology in each field of application. Our primary objective is to show how Ethernet has been enhanced to comply with the specific requirements of several application fields, particularly in transport, embedded and multimedia contexts. The paper first describes the common Ethernet LAN technology and highlights its main features. It reviews the most important specific Ethernet versions with respect to each application field’s requirements. Finally, we compare these different fields of application and we particularly focus on the fundamental concepts and the quality of service capabilities of each proposal

Root Failure Analysis in Meshed Tree Networks

Mesh topologies play a vital role in switched networks. Broadcast storms due to the loops in Mesh Networks are a major concern in switched networks. Logical spanning trees are constructed using algorithms like spanning tree algorithm to avoid loops and hence address the broadcast storm problem. However, in the event of a topology change or a link failure in the network, it takes time to converge and construct new spanning tree to forward frames. Link State routing and other protocols like Rapid Spanning Tree protocol[2][19] were introduced to address the problems of high convergence times in the basic spanning tree protocol(STP) in the event of network component failures. A much efficient and advanced approach was offered with Mesh Tree Protocol based on the Mesh Tree Algorithm. Mesh Tree Protocol constructs multiple tree branches from a single root and quickly falls back to an alternate path or switch in case of link or switch failures. This cuts down the convergence delays considerably. The Mesh Tree Protocol based on the Mesh Tree Algorithm is currently under development as an IEEE standard. Other major changes in the MTP compared to the already existing protocols is that the root is manually assigned instead of using the root election procedure. This will cut down the delays during instantiation of the protocol but also has risk concerning the action of the protocol if the manually assigned root fails. To address this concern, an enhancement to the Mesh Tree protocol is being researched in this thesis. The idea is to implement a Multiple Meshed Tree algorithm where meshed trees will be constructed from multiple roots. This thesis introduces root redundancy in the Mesh Tree Protocol and will be assessed for performance improvements on root failures in comparison with Rapid Spanning Tree Protocol (RSTP) which re-elects a root switch on the current root switch failure

Redundant IEC 61850 communication protocols in substation automation

The standard IEC 61850 has been adopted with open arms by the power system automation market. The first version of the standard published in 2005 did not however pay any attention to redundant communication aspects of the substation automation network. The recent extensions to the standard however corrected this defect and bring redundancy into view, adopting two high availability redundancy protocols from the existing standard IEC 62439-3: Parallel Redundancy Protocol (PRP) and High-availability Seamless Redundancy (HSR). These two protocols provide seamless (0 s.) network recovery times and fulfill even the most demanding requirements for substation automation network. In this thesis, these two redundancy protocols, their usage and possibilities in substation automation are investigated. At first, the IEC 61850 features, substation communication network topologies, and also the redundancy protocols and methods used today are presented. After this, the protocols PRP and HSR are discussed more deeply. The theoretical part is followed by a test of a system with PRP and ABB devices to give general notes and clarify possible problems when building such a system, and to investigate if the ABB PRP implementation is accordant with the standard IEC 62439-3. The objective of this thesis was to bring information and early experience about the two high-availability redundancy protocols, as they will be gradually introduced in the projects of the target company. The test confirmed that the current PRP version is ready to be used with the few ABB substation automation products that support it at the moment. However, a new version of PRP has been introduced and it will gradually replace the present version, bringing compatibility with HSR networks. HSR is not yet found on the market, but is expected to come to use in the very near future.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

Switches auto-configuráveis

Mestrado em Engenharia Electrónica e TelecomunicaçõesO protocolo Spanning Tree é antigo e completamente desajustado às necessidades das redes Ethernet de hoje em dia. Os seus sucessores, Rapid Spanning Tree Protocol e Multiple Spanning Trees apresentam igualmente problemas de estabilidade e tempos de convergência inadequados. Recentemente foram propostos para standardização, dois novos protocolos que visam a substituição desses protocolos baseados em árvores abrangentes (spanning trees): o TRILL, por parte do IETF, e o SPB, por parte do IEEE. Muito embora sejam idênticos em diversas características, apresentam paradigmas de encaminhamento bastante distintos. O TRILL actua como um protocolo de Layer 3, enquanto que o SPB comporta-se como um típico protocolo de Layer 2. Tanto o TRILL como o SPB adequam-se a grandes redes Ethernet, requerem muito processamento das máquinas e implicam avultados investimentos em novos equipamentos. O protocolo Self-Configurable Switches (SCS) visa substituir os protocolos de spanning tree, alterando radicalmente a filosofia de encaminhamento e controlo de tramas nas redes Ethernet, mas mantendo-se adequado ao segmento dos equipamentos e redes que actualmente correm esses protocolos de spanning tree, minimizando assim potenciais investimentos exagerados. Esta tese apresenta um resumo das funcionalidades e problemas dos actuais protocolos de spanning tree, as principais características dos novos protocolos propostos a standardização e os processos e mecanismos do novo protocolo Self-Configurable Switches (SCS). No final, são apresentados resultados de testes comparativos de funcionalidade, aplicabilidade e performance do protocolo SCS versus os protocolos de spanning tree, que atestam o desempenho superior do protocolo SCS.The Spanning Tree Protocol is old and completely misadjusted towards current Ethernet networks requirements. Its successors, Rapid Spanning Tree Protocol and Multiple Spanning Trees reveal also stability problems and poor convergence times. Recently two new protocols aiming spanning tree protocols substitution were proposed to standard: IETF’s TRILL and IEEE’s SPB. Although similar in many aspects, their forwarding paradigms are quite different. TRILL acts like a Layer 3 protocol, whereas SPB keeps the typical Layer 2 protocol behaviour. Both TRILL and SPB target backbone or core Ethernet networks, requiring great processing power from bridges and huge investment in new gear. Self-Configurable Switches protocol (SCS) objective is to replace the spanning tree protocols, changing radically the frame forwarding and control philosophy over Ethernet networks, but keep being suitable to the range of equipment and networks that tipically run those spanning tree protocols, minimizing potential large investments. This thesis presents an overview of all features and problems of spanning tree protocols, the main characteristics of the new proposal standards and the processes and mechanisms of the new Self-Configurable Switches protocol. At the end, test results are presented regarding features, feasability and performance of SCS protocol versus the spanning tree protocols, which attest SCS protocol superior performance

Feasibility of wireless mesh for LTE-Advanced small cell access backhaul

Mobiilidatan määrä on muutaman viime vuoden aikana kasvanut voimakkaasti ja nykyiset ennustukset arvioivat eksponentiaalista kasvukäyrää tulevien vuosien aikana. Matkapuhelinjärjestelmät ovat kehittyneet nopeasti tämän trendin ohjaamana. Neljännen sukupolven matkapuhelinverkkostandardien myötä, uudet innovaatiot kuten heterogeeniset verkkoratkaisut tarjoavat ratkaisun nykyisiin skaalautuvuus- ja kapasiteettiongelmiin. Joitain ilmeisiä ongelmakohtiakin kuitenkin esiintyy kuten heterogeenisten verkkojen runkokytkennän toteuttaminen. Yksi lupaavimmista tavoista toteuttaa heterogeenisten verkkojen runkokytkentä on langaton ja itseorganisoituva mesh-verkko. Tämän opinnäytetyön tavoitteena on varmistaa ja testata Nokia Siemens Networksin kehittämän mesh-runkokytkentäverkkokonseptin toteutettavuutta ja toiminnallisuutta soveltuvan validointijärjestelmän avulla. Kaiken kaikkiaan validointijärjestelmä ja sen päälle toteutettu mesh-protokolla toimivat moitteettomasti koko kehitys- ja testausprosessin ajan. Konseptin eri ominaisuudet ja mekanismit todistettiin täysin toteutettaviksi ja toimiviksi. Muutamalla lisäominaisuudella ja konseptiparannuksella mesh-konsepti tarjoaa houkuttelevan ja innovatiivisen ratkaisun heterogeenisten verkkojen runkokytkentään tulevaisuudessa.Mobile traffic demands and volumes are increasing and will dramatically keep increasing in the future. Along with this, mobile networks have evolved to better match this growth. Fourth generation cellular network standard introduced a set of new innovations for mobile communications, including support for heterogeneous network deployments. Heterogeneous networking is the likely answer for future mobile data capacity shortage but also poses some challenges, the most evident being how to implement the backhauling. One of the most promising heterogeneous network backhaul solutions is a meshed radio system with self-organizing features. The main scope of this master's thesis is the verification of functionality and feasibility of a wireless mesh backhaul concept developed by Nokia Siemens Networks through a proof-of-concept system. All in all, the wireless mesh proof-of-concept system performed strongly throughout the development and testing process. The different functionalities were proven to work successfully together. With further development and enhancement, the system concept displays extreme potential for a state-of-the-art heterogeneous network backhaul technology

Deliverable JRA1.1: Evaluation of current network control and management planes for multi-domain network infrastructure

This deliverable includes a compilation and evaluation of available control and management architectures and protocols applicable to a multilayer infrastructure in a multi-domain Virtual Network environment.The scope of this deliverable is mainly focused on the virtualisation of the resources within a network and at processing nodes. The virtualization of the FEDERICA infrastructure allows the provisioning of its available resources to users by means of FEDERICA slices. A slice is seen by the user as a real physical network under his/her domain, however it maps to a logical partition (a virtual instance) of the physical FEDERICA resources. A slice is built to exhibit to the highest degree all the principles applicable to a physical network (isolation, reproducibility, manageability, ...). Currently, there are no standard definitions available for network virtualization or its associated architectures. Therefore, this deliverable proposes the Virtual Network layer architecture and evaluates a set of Management- and Control Planes that can be used for the partitioning and virtualization of the FEDERICA network resources. This evaluation has been performed taking into account an initial set of FEDERICA requirements; a possible extension of the selected tools will be evaluated in future deliverables. The studies described in this deliverable define the virtual architecture of the FEDERICA infrastructure. During this activity, the need has been recognised to establish a new set of basic definitions (taxonomy) for the building blocks that compose the so-called slice, i.e. the virtual network instantiation (which is virtual with regard to the abstracted view made of the building blocks of the FEDERICA infrastructure) and its architectural plane representation. These definitions will be established as a common nomenclature for the FEDERICA project. Other important aspects when defining a new architecture are the user requirements. It is crucial that the resulting architecture fits the demands that users may have. Since this deliverable has been produced at the same time as the contact process with users, made by the project activities related to the Use Case definitions, JRA1 has proposed a set of basic Use Cases to be considered as starting point for its internal studies. When researchers want to experiment with their developments, they need not only network resources on their slices, but also a slice of the processing resources. These processing slice resources are understood as virtual machine instances that users can use to make them behave as software routers or end nodes, on which to download the software protocols or applications they have produced and want to assess in a realistic environment. Hence, this deliverable also studies the APIs of several virtual machine management software products in order to identify which best suits FEDERICA’s needs.Postprint (published version

Fairness in a data center

Existing data centers utilize several networking technologies in order to handle the performance requirements of different workloads. Maintaining diverse networking technologies increases complexity and is not cost effective. This results in the current trend to converge all traffic into a single networking fabric. Ethernet is both cost-effective and ubiquitous, and as such it has been chosen as the technology of choice for the converged fabric. However, traditional Ethernet does not satisfy the needs of all traffic workloads, for the most part, due to its lossy nature and, therefore, has to be enhanced to allow for full convergence. The resulting technology, Data Center Bridging (DCB), is a new set of standards defined by the IEEE to make Ethernet lossless even in the presence of congestion. As with any new networking technology, it is critical to analyze how the different protocols within DCB interact with each other as well as how each protocol interacts with existing technologies in other layers of the protocol stack. This dissertation presents two novel schemes that address critical issues in DCB networks: fairness with respect to packet lengths and fairness with respect to flow control and bandwidth utilization. The Deficit Round Robin with Adaptive Weight Control (DRR-AWC) algorithm actively monitors the incoming streams and adjusts the scheduling weights of the outbound port. The algorithm was implemented on a real DCB switch and shown to increase fairness for traffic consisting of mixed-length packets. Targeted Priority-based Flow Control (TPFC) provides a hop-by-hop flow control mechanism that restricts the flow of aggressor streams while allowing victim streams to continue unimpeded. Two variants of the targeting mechanism within TPFC are presented and their performance evaluated through simulation