HURP/HURBA: Zero-configuration hierarchical Up/Down routing and bridging architecture for Ethernet backbones and campus networks

Ethernet switched networks do not scale appropriately due to limitations inherent to the spanning tree protocol. Ethernet architectures based on routing over a virtual topology in which turns are prohibited offer improved performance over spanning tree, although in some cases suffer from excessive computational complexity. Up/Down routing is a turn prohibition algorithm with low computational complexity. In this paper we propose HURBA, a new layer-two architecture that improves Up/Down routing performance due to an optimization based on the use of hierarchical addressing, while preserving the computational complexity of Up/Down. The resulting architecture requires zero-configuration, uses the same frame format as Ethernet, allows upgrades by software update, and is compatible with 802.1D bridges by means of encapsulation. HURP protocol builds automatically a core with the interconnected HURP routing bridges and the standard bridges get connected to the edges in standard spanning trees. Simulations show that the performance of HURP, evaluated over various combinations of network topology and size, is close to the one of shortest path, is consistently better than that of Up/Down, and is equal or better than Turn Prohibition, with the advantage of having a lower complexity.En prens

Multicast Mobility in Mobile IP Version 6 (MIPv6) : Problem Statement and Brief Survey

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Interoperability between WiMAX and broadband mobile space networks

In several countries manufacturers, operators, and public authorities look at WiMAX system as a viable technology to fill the "digital divide," providing broadband services mainly in suburban and rural areas, but also in densely populated areas. Nevertheless, as a standalone system it will never offer global services, and to complement its capabilities, the utilization of broadband space-based access shared among users represents a scalable and cost-effective solution to offer wider area coverage, improved performance in terms of QoS, service continuity in case of terrestrial network failure, and long-range user mobility. Integration between WiMAX and a space-based infrastructure, composed of a combination of satellites and high altitude platforms, can be pursued in several ways. The simplest solution is based on connecting a WiMAX network by means of a terrestrial network terminating at a hub station connected to the space infrastructure. A more flexible solution should allow the WiMAX subscriber station or base station to directly access the space infrastructure. This article addresses the identification of suitable scenarios and a feasibility analysis presenting link budget results related to a subset of the identified solutions

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

Automotive Ethernet architecture and security: challenges and technologies

Vehicle infrastructure must address the challenges posed by today's advances toward connected and autonomous vehicles. To allow for more flexible architectures, high-bandwidth connections and scalability are needed to connect many sensors and electronic control units (ECUs). At the same time, deterministic and low latency is a critical and significant design requirement to support urgent real-time applications in autonomous vehicles. As a recent solution, the time-sensitive network (TSN) was introduced as Ethernet-based amendments in IEEE 802.1 TSN standards to meet those needs. However, it had hurdle to be overcome before it can be used effectively. This paper discusses the latest studies concerning the automotive Ethernet requirements, including transmission delay studies to improve worst-case end-to-end delay and end-to-end jitter. Also, the paper focuses on the securing Ethernet-based in-vehicle networks (IVNs) by reviewing new encryption and authentication methods and approaches