Optimal design of switched Ethernet networks implementing the Multiple Spanning Tree Protocol

International audienceSwitched Ethernet networks rely on the Spanning Tree Protocol (STP) to ensure a cycle-free connectivity between nodes, by reducing the topology of the network to a spanning tree. The Multiple Spanning Tree Protocol (MSTP) allows for the providers to partition the traffic in the network and assign it to different virtual local area networks, each satisfying the STP. In this manner, it is possible to make a more efficient use of the physical resources in the network. In this paper we consider the traffic engineering problem of finding optimal designs of switched Ethernet networks implementing the MSTP, such that the worst-case link utilization is minimized. We show that this problem is N P-hard. We propose three mixed-integer linear programming formulations for this problem. Through a large set of computational experiments, we compare the performance of these formulations. Until now, the problem was almost exclusively solved with heuristics. Our objective here is provide a first comparison of different models that can be used in exact methods

Routed end-to-end Ethernet : Proof of Concept

Tämän diplomityön tavoitteena on tutkia ja analysoida Ethernet- ja IEEE 802.1 -standardeja, sekä IPv4- ja IPv6-protokollia. Näiden parhaita puolia yhdistämällä kehitettiin uusi päästä-päähän reitittävä Ethernet -konsepti, jonka mukaan rakennettiin Proof of Concept -verkko. Tämä idea pyrkii ratkaisemaan Internetin suurimman ongelman, jossa osoiteavaruudesta loppuvat osoitteet, käyttämällä laitteiden identifioimiseen ja Ethernet-pakettien reitittämiseen sekä MAC- että NSAP-osoitteita. Hierarkkisuuden puute osoitteissa estää tehokkaan reitityksen ja sen takia Ethernet-verkot eivät skaalaudu maailmanlaajuiseksi verkoksi. IEEE 802.1 -standardeissa on parannettu Ethernet-verkkojen skaalautuvuutta, mutta osoitteistusta ei ole muutettu ja reititykseen käytetään edelleen Spanning Tree -protokollaa. Internet-protokollan versio 4:stä tuli Internetin hallitseva verkkoprotokolla, koska siinä osoitteisto on hierarkkinen, mikä mahdollistaa tehokkaan reitityksen. Ongelmaksi on kuitenkin muodostunut pieni osoiteavaruus, josta osoitteet alkavat loppua. IPv6:ssa on suurempi osoiteavaruus, mutta siltikään se ei ole syrjäyttänyt IPv4-osoitteita. RE2EE:n ideana on lisätä Ethernet-verkkoon hierarkkiset osoitteet, jotka yhdessä mahdollistaisivat riittävän ison osoiteavaruuden ja tehokkaan reitityksen. Proof of Conceptissa luotiin RE2EE-verkko pienessä mittakaavassa ja todistettiin sen avulla RE2EE:n perusominaisuuksin toteuttaminen käyttämällä ainoastaan Ethernet-paketteja.The main goal of this thesis is to investigate and analyse the Ethernet and IEEE 802.1 standards, and IPv4 and IPv6 protocols. From those combine a new idea of Routed End-to-End Ethernet in theory and to build a Proof of Concept network that shows it in a small scale. This concept would solve the address exhaustion problem by using MAC and NSAP addresses for host identification and for routing Ethernet packets in the network. From Ethernet and IEEE 802.1 standards we found that the main problem of the Ethernet is that it does not have hierarchical addresses. Hierarchical addresses would allow efficient routing enabling the network to scale globally. IEEE 802.1 has many standards with features for scaling Ethernet networks better, but they are still not enough. The only routing protocols used in the Ethernet networks are still the Spanning Tree Protocols. Internet Protocol version 4 that is the dominant network protocol in the Internet, has a hierarchical address space enabling efficient routing. A big problem with IPv4 is that the address space is small and is running out of addresses. IPv6 has larger address space, but for some reason the deployment is really slow. RE2EE would use Ethernet added with hierarchical addresses for the Internet. This would make the address space large enough and also efficient routing would be possible. In the Proof of Concept a small scale network was built, which showed that it is possible to create the basic functionalities of RE2EE using only Ethernet packets

Novel algorithms for fair bandwidth sharing on counter rotating rings

Rings are often preferred technology for networks as ring networks can virtually create fully connected mesh networks efficiently and they are also easy to manage. However, providing fair service to all the stations on the ring is not always easy to achieve. In order to capitalize on the advantages of ring networks, new buffer insertion techniques, such as Spatial Reuse Protocol (SRP), were introduced in early 2000s. As a result, a new standard known as IEEE 802.17 Resilient Packet Ring was defined in 2004 by the IEEE Resilient Packet Ring (RPR) Working Group. Since then two addenda have been introduced; namely, IEEE 802.17a and IEEE 802.17b in 2006 and 2010, respectively. During this standardization process, weighted fairness and queue management schemes were proposed to be used in the standard. As shown in this dissertation, these schemes can be applied to solve the fairness issues noted widely in the research community as radical changes are not practical to introduce within the context of a standard. In this dissertation, the weighted fairness aspects of IEEE 802.17 RPR (in the aggressive mode of operation) are studied; various properties are demonstrated and observed via network simulations, and additional improvements are suggested. These aspects have not been well studied until now, and can be used to alleviate some of the issues observed in the fairness algorithm under some scenarios. Also, this dissertation focuses on the RPR Medium Access Control (MAC) Client implementation of the IEEE 802.17 RPR MAC in the aggressive mode of operation and introduces a new active queue management scheme for ring networks that achieves higher overall utilization of the ring bandwidth with simpler and less expensive implementation than the generic implementation provided in the standard. The two schemes introduced in this dissertation provide performance comparable to the per destination queuing implementation, which yields the best achievable performance at the expense of the cost of implementation. In addition, till now the requirements for sizing secondary transit queue of IEEE 802.17 RPR stations (in the aggressive mode of operation) have not been properly investigated. The analysis and suggested improvements presented in this dissertation are then supported by performance evaluation results and theoretical calculations. Last, but not least, the impact of using different capacity links on the same ring has not been investigated before from the ring utilization and fairness points of view. This dissertation also investigates utilizing different capacity links in RPR and proposes a mechanism to support the same

Survivability schemes for metro ethernet networks

Ph.DDOCTOR OF PHILOSOPH

Introduction to the LaRC central scientific computing complex

The computers and associated equipment that make up the Central Scientific Computing Complex of the Langley Research Center are briefly described. The electronic networks that provide access to the various components of the complex and a number of areas that can be used by Langley and contractors staff for special applications (scientific visualization, image processing, software engineering, and grid generation) are also described. Flight simulation facilities that use the central computers are described. Management of the complex, procedures for its use, and available services and resources are discussed. This document is intended for new users of the complex, for current users who wish to keep appraised of changes, and for visitors who need to understand the role of central scientific computers at Langley

Optimal Design Strategies for Survivable Carrier Ethernet Networks

Ethernet technologies have evolved through enormous standardization efforts over the past two decades to achieve carrier-grade functionalities, leading to carrier Ethernet. Carrier Ethernet is expected to dominate next generation backbone networks due to its low-cost and simplicity. Ethernet's ability to provide carrier-grade Layer-2 protection switching with SONET/SDH-like fast restoration time is achieved by a new protection switching protocol, Ethernet Ring Protection (ERP). In this thesis, we address two important design aspects of carrier Ethernet networks, namely, survivable design of ERP-based Ethernet transport networks together with energy efficient network design. For the former, we address the problem of optimal resource allocation while designing logical ERP for deployment and model the combinatorially complex problem of joint Ring Protection Link (RPL) placements and ring hierarchies selection as an optimization problem. We develop several Mixed Integer Linear Programming (MILP) model to solve the problem optimally considering both single link failure and concurrent dual link failure scenarios. We also present a traffic engineering based ERP design approach and develop corresponding MILP design models for configuring either single or multiple logical ERP instances over one underlying physical ring. For the latter, we propose two novel architectures of energy efficient Ethernet switches using passive optical correlators for optical bypassing as well as using energy efficient Ethernet (EEE) ports for traffic aggregation and forwarding. We develop an optimal frame scheduling model for EEE ports to ensure minimal energy consumption by using packet coalescing and efficient scheduling

An Introduction to Computer Networks

An open textbook for undergraduate and graduate courses on computer networks

Quality of service modeling and analysis for carrier ethernet

Today, Ethernet is moving into the mainstream evolving into a carrier grade technology. Termed as Carrier Ethernet it is expected to overcome most of the\ud shortcomings of native Ethernet. It is envisioned to carry services end-to-end serving corporate data networking and broadband access demands as well as backhauling wireless traffic. As the penetration of Ethernet increases, the offered Quality of Service (QoS) will become increasingly important and a distinguishing factor between different service providers. The challenge is to meet the QoS requirements of end applications such as response times, throughput, delay and jitter by managing the network resources at hand. Since Ethernet was not designed to operate in large public networks it does not possess functionalities to address this issue. In this thesis we propose and analyze mechanisms which improve the QoS performance of Ethernet enabling it to meet the demands of the current and next generation services and applications.\u

White RHINO: a low-cost communications radar hardware platform

Includes bibliographical referencesThe Electromagnetic spectrum has always been a very expensive resource and hence, has not been accessible to everyone. Yet, it is under-utilized. The new Whitespace Technology standards provide an efficient way to use the spectrum. However, the concept of shared spectrum introduced by the Whitespace Technology promises to reduce the cost of accessing the spectrum by a huge margin. Also, because the standards utilize the television channels, the VHF and UHF frequencies facilitate wireless transmission over large distances. This has provided impetus to various application developers. Using Whitespace Technology for Communications Radar is one such novel application which has great benefits for the African scenario. Here, the population is scattered and infrastructure for navigation and tracking is inadequate. But, there is a shortage of low-cost commercially available hardware platforms tailored for the application. In order to boost Whitespace-based Communications Radar application development, the White RHINO(Reconfigurable Hardware Interface for computation and radio) hardware platform was developed. It aims to fill the gap of low-cost commercial hardware platforms available for Whitespace-based Communications Radar. Being a Communications Radar platform, the White RHINO had to be designed keeping the standards and regulating body norms as yardsticks. However, an achievable radar performance of the platform under various scenarios was also estimated. The White RHINO contains an FPGA (the Zynq7000 series) which has dual embedded ARM processing cores. For the wireless interface, it contains a field programmable RF transceiver and an RF frontend section. The platform contains wired networking capability of 2 Gbps. The platform also has 512 MB DDR3 and 128 Mbit NAND ash as onboard memory. Finally, it has USB host, SDIO and JTAG for programmability and temperature sensors for system monitoring. The manufactured boards were tested under lab environment. It was found that except a failure on the RF transceiver section (due to a PCB footprint error), other interfaces were functional. The White RHINO successfully runs both U-Boot and Linux as operating systems. The error and other minor bugs have been corrected for the next fabrication run. Also, the cost of the complete White RHINO system is less than 1000 USD which makes it a very powerful platform and yet, less expensive than most of the commercially available platforms designed for similar applications

Analysis of Ethernet Powerlink network and development of a wireless extension based on the IEEE 802.11n WLAN

In questa tesi si analizza inizialmente Ethernet POWERLINK (EPL), una delle reti Ethernet Real-Time più popolari grazie alle sue caratteristiche e prestazioni. Viene poi proposta l'estensione wireless della rete POWERLINK basata sulla rete IEEE 802.11n (WLAN), con quest'ultima opportunamente ottimizzata per la comunicazione industriale attraverso l'algoritmo di dynamic rate adaptation RSIN