<p>Ethernet är den standard som används nästan överallt för nätverk i hemmen, på kontor och i industrier. Varken Ethernet eller switchat Ethernet är gjorda för att hantera realtidskommunikation då tiden det tar att skicka ett meddelande inte alltid sker inom en förutsägbar tid.</p><p>I denna rapport presenteras ett protokoll som tillåter feltolerant dynamisk schemaläggning av kanaler över ett switchat Ethernet. Protokollet är en vidareutveckling av tidigare arbete (ThrottleNet) som gjorts inom området där realtidstrafik ska garanteras över ett switchat Ethernet. Till skillnad från tidigare arbete använder sig detta protokoll av kritikaliteter för att explicit visa skillnaden mellan de kanaler som får tas bort och de kanaler som inte får tas bort. Kanalerna schemaläggs vid kortvariga överbelastningar för att optimera användningen av tillgängliga resurser baserat på hur värdefulla och kritiska kanalerna är för systemet.</p>

Thèse doctorat : Informatique : Rennes 1 : 2007. / Bibliogr. p. 119-125.

Zugl.: Berlin, Techn. Univ., Diss., 2007 / Hergestellt on demand

Thesis (M.S.)--Florida State University, 2003. / Advisor: Dr. Xin Yuan, Florida State University, College of Arts and Sciences, Dept. of Computer Science. Title and description from dissertation home page (viewed Apr. 7, 2004). Includes bibliographical references.

Thesis (M.S. in Computer Science)--Naval Postgraduate School, September 2003. / Thesis advisor(s): Geoffrey Xie, John Gibson. Includes bibliographical references (p. 75-76). Also available online.

Electricity generation for Information and Communications Technology (ICT) contributes over 2% of the human-generated CO2 to the atmosphere. Energy costs are rapidly becoming the major operational expense for ICT and may soon dwarf capital expenses as software and hardware continue to drop in price. In this dissertation, three new approaches to achieving energy-proportional operation of network links and data servers are explored. Ethernet is the dominant wireline communications technology for Internet connectivity. IEEE 802.3az Energy Efficient Ethernet (EEE) describes a Low Power Idle (LPI) mechanism for allowing Ethernet links to sleep. A method of coalescing packets to consolidate link idle periods is investigated. It is shown that packet coalescing can result in almost fully energy-proportional behavior of an Ethernet link. Simulation is done at both the queuing and protocol levels for a range of traffic models and system configurations. Analytical modeling is used to gain a deeper general insight into packet coalescing. The architecture of a hybrid web server based on two platforms - a low-power (ARM based) and a high-power (Pentium based) - can be used to achieve step-wise energy-proportional operation and maintain headroom for peak loads. A new method based on Gratuitous ARP for switching between two mirrored platforms is developed, prototyped, and evaluated. Experimental results show that for up to 50 requests per minute, a hybrid server where the Master platform is a 2012 server-grade desktop PC can sleep for 50% of time with no increase in response time. HTTP can be used for redirection in space - a new method for precise redirection in time is proposed and used to schedule requests to a high-power server in a hybrid server. The scheduling method is modeled as a single server queue with vacations where the vacation duration is fixed and the service distribution is directly a function of the request load. This approach is well suited for delay tolerant applications such as application updates and file back-up. Energy-proportional operation is shown to be achievable in a prototype system. A first-order estimation with conservative assumptions on the adoption rate of the methods proposed and studied here shows that these methods can collectively enable energy savings in the order of hundreds of million dollars in the US annually.

The amount of electricity consumed by devices connected to the Internet in the U.S. has rapidly increased and now amounts to over 2% of total electricity used, which is about 74 TWh/yr costing over $6 billion annually. This energy use can be categorized as direct and induced. Much of this energy powers idle links, switches, and network-connected hosts and is thus wasted.This dissertation contains the first-ever investigation into the energy efficiency of Ethernet networks. A method for matching Ethernet link data rate with link utilization, called Adaptive Link Rate (ALR), is designed and evaluated. ALR consists of a mechanism to change the link data rate and a policy to determine when to change the data rate. The focus of this dissertation is on the analysis and simulation evaluation of two ALR policies. The simplest ALR policy uses output buffer thresholds to determine when to change data rate. This policy is modeled using a Markov chain. A specific challenge was modeling a state-dependent service rate queue with rate transition only at service completion. This policy was shown to be unstable in some cases, and an improved policy based on explicit utilization measurement was investigated. This more complex policy was evaluated using simulation. A synthetic traffic generator was developed to create realistic synthetic network traffic traces for the simulation evaluation. Finally, an improved method for detecting long idle periods using quantile estimation was investigated.Characterization of network traffic showed that proxying by a low power device for a high power device is feasible. A prototype proxy for a Web server was developed and studied. To maintain TCP connections during sleep time periods of a host, a new split TCP connection method was designed. The split connection method was prototyped and shown to be invisible to a telnet session.This research has contributed to the formation of an IEEE 802.3 Energy Efficient Ethernet study group. It is thus very likely that ALR will become a standard and will achieve industry implementation and widespread deployment. This will result in energy savings of hundreds of millions of dollars per year in the U.S. alone.

ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CA / Yuma Proving Ground (YPG) personnel developed the Video Bus Integrated Telemetry System (VBITS) for air delivery testing at YPG. The system consists of a common rack for mounting both video and telemetry equipment, which makes installation easier and more time efficient. Prior to the one-rack concept, the video, TSPI, and telemetry were all installed as separate entities competing for space, power, and time. Requirements to downlink High-Definition (HD) video from the aircraft prompted research into technological improvements in transmitters, onboard encoders, and recorders. These advances allowed the integration of video, analog sensors, and aircraft bus data into a single telemetry stream. Future advancements will include combining multiple HD video sources in a single downlink.

ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CA / Ethernet-based data acquisition systems are becoming more and more common in the Flight Test Instrumentation environment. Digitized analog sensor output and various other types of digital data is captured and inserted into Ethernet packets using a "packet fill" strategy that in general is under control of the user. This paper discuss and compares two strategies "FILL-TO-TIME" and "FILL-TO- SIZE" for the acquisition of ARINC-429 digital data bus.

Ethernet as the communication medium in the enterprise data center has outlived all competing mediums and resisted the test of time with regards to speed and costs. The future is also poised for growth with 40 and 100Gps speeds just over horizon. The current state of the technology is being enhanced and extended with lossless features to allow for fabric convergence of Storage and Inter Process Communication (IPC) Networks. It is under this medium that an increase in the adoption of Remote Direct Memory Access (RDMA) over Ethernet using offloaded TCP/IP (iWARP) and Infiniband over Ethernet (RoCE) communication stacks to RDMA capable NIC adapter s (RNIC) is observed. RDMA enables direct application to application communication over the network resulting in numerous and significant benefits such as reduced CPU utilization, lower latency communications, increased energy efficiency, and reduced overall system requirements. However, with said benefits also comes increased software complexity in how RDMA interface users communicate. The RDMA communication semantics, which originate from the HPC domain, are heavily biased towards Low-Latency and High-Bandwidth communications rather than Reliability, Availability, and Serviceability (RAS). As adoption increases, and enterprise data centers begins to leverage RDMA over Ethernet, enhancements to the OS stack software architecture and design of the components involved is required to address these deficiencies. Operating system interfaces, device drivers, adapter hardware design, and embedded firmware features must be viewed from a high-availability and maintainability point of view. RAS enhancements for RDMA communications proposes the software architectural tradeoffs for enhancing the iWARP and RoCE RDMA implementations for communications in the enterprise data center, with new and traditional RAS features for existing communications stacks and devices. The architecture leverages software enhancements in traceability, availability, maintainability, serviceability, fault-isolation and resource management; such that in the advent of errors, the probability that the forensics data points to identify root cause are immediately and automatically available is increased. / text