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PingER Project
PingER, an acronym for Ping End-to-end Reporting, measures round-trip travel time of a packet of data between two nodes on the Internet. The PingER' Project uses a simple tool—the ping command—to get valuable insights into performance of the Internet backbone. High energy particle physicists began the project in 1995, because they needed to access large amounts of data at laboratories sometimes as far away as across an ocean. They needed to know how the Internet was performing, identify problems, and apply solutions. At U.S.Department of Energy's SLAC National Accelerator Laboratory, PingER let researcher Les Cottrell "keep tabs on how parts of the network were performing and root out any problems." PingER is one of several collaborative projects having measurement infrastructures for monitoring Internet Traffic. How PingER works Using the ping command, monitoring nodes initiate transmissions to remote nodes, then measure and record the response times, or the lack of r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ping (networking Utility)
ping is a computer network administration software utility used to test the reachability of a host on an Internet Protocol (IP) network. It is available for virtually all operating systems that have networking capability, including most embedded network administration software. Ping measures the round-trip time for messages sent from the originating host to a destination computer that are echoed back to the source. The name comes from active sonar terminology that sends a pulse of sound and listens for the echo to detect objects under water. Ping operates by means of Internet Control Message Protocol (ICMP) packets. ''Pinging'' involves sending an ICMP echo request to the target host and waiting for an ICMP echo reply. The program reports errors, packet loss, and a statistical summary of the results, typically including the minimum, maximum, the mean round-trip times, and standard deviation of the mean. The command-line options of the ping utility and its output vary bet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Internet Backbone
The Internet backbone may be defined by the principal data routes between large, strategically interconnected computer networks and core routers of the Internet. These data routes are hosted by commercial, government, academic and other high-capacity network centers, as well as the Internet exchange points and network access points, that exchange Internet traffic between the countries, continents, and across the oceans. Internet service providers, often Tier 1 networks, participate in Internet backbone traffic by privately negotiated interconnection agreements, primarily governed by the principle of settlement-free peering. The Internet, and consequently its backbone networks, do not rely on central control or coordinating facilities, nor do they implement any global network policies. The resilience of the Internet results from its principal architectural features, most notably the idea of placing as few network state and control functions as possible in the network elemen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Physics
Particle physics or high energy physics is the study of fundamental particles and forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) and bosons (force-carrying particles). There are three generations of fermions, but ordinary matter is made only from the first fermion generation. The first generation consists of up and down quarks which form protons and neutrons, and electrons and electron neutrinos. The three fundamental interactions known to be mediated by bosons are electromagnetism, the weak interaction, and the strong interaction. Quarks cannot exist on their own but form hadrons. Hadrons that contain an odd number of quarks are called baryons and those that contain an even number are called mesons. Two baryons, the proton and the neutron, make up most of the mass of ordinary matter. Mesons are unstable and the longest-lived last for only a few hundre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Department Of Energy National Laboratories
The United States Department of Energy National Laboratories and Technology Centers is a system of facilities and laboratories overseen by the United States Department of Energy (DOE) for scientific and technological research. Sixteen of the seventeen DOE national laboratories are federally funded research and development centers administered, managed, operated and staffed by private-sector organizations under management and operating (M&O) contract with DOE (with the National Energy Technology Laboratory being the exception). History The system of centralized national laboratories grew out of the massive scientific endeavors of World War II, in which new technologies such as radar, the computer, the proximity fuse, and the atomic bomb proved decisive for the Allied victory. Though the United States government had begun seriously investing in scientific research for national security in World War I, it was only in late 1930s and 1940s that monumental amounts of resources ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SLAC National Accelerator Laboratory
SLAC National Accelerator Laboratory, originally named the Stanford Linear Accelerator Center, is a United States Department of Energy National Laboratory operated by Stanford University under the programmatic direction of the U.S. Department of Energy Office of Science and located in Menlo Park, California. It is the site of the Stanford Linear Accelerator, a 3.2 kilometer (2-mile) linear accelerator constructed in 1966 and shut down in the 2000s, that could accelerate electrons to energies of 50 GeV. Today SLAC research centers on a broad program in atomic and solid-state physics, chemistry, biology, and medicine using X-rays from synchrotron radiation and a free-electron laser as well as experimental and theoretical research in elementary particle physics, astroparticle physics, and cosmology. History Founded in 1962 as the Stanford Linear Accelerator Center, the facility is located on of Stanford University-owned land on Sand Hill Road in Menlo Park, Californi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latency (engineering)
Latency, from a general point of view, is a time delay between the cause and the effect of some physical change in the system being observed. Lag, as it is known in gaming circles, refers to the latency between the input to a simulation and the visual or auditory response, often occurring because of network delay in online games. Latency is physically a consequence of the limited velocity at which any physical interaction can propagate. The magnitude of this velocity is always less than or equal to the speed of light. Therefore, every physical system with any physical separation (distance) between cause and effect will experience some sort of latency, regardless of the nature of the stimulation at which it has been exposed to. The precise definition of latency depends on the system being observed or the nature of the simulation. In communications, the lower limit of latency is determined by the medium being used to transfer information. In reliable two-way communication ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Packet Delay Variation
In computer networking, packet delay variation (PDV) is the difference in end-to-end one-way delay between selected packets in a flow with any lost packets being ignored.RFC 3393 The effect is sometimes referred to as packet jitter, although the definition is an imprecise fit. Terminology The term PDV is defined in ITU-T Recommendation Y.1540Internet protocol data communication service - IP packet transfer and availability performance parameters section 6.2. In computer networking, although not in electronics, usage of the term jitter may cause confusion. From RFC 3393 (section 1.1): The variation in packet delay is sometimes called "jitter". This term, however, causes confusion because it is used in different ways by different groups of people. ... In this document we will avoid the term "jitter" whenever possible and stick to delay variation which is more precise. Measurement of packet delay variation The means of packet selection for measurement is not specified in RFC 33 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Packet Loss
Packet loss occurs when one or more packets of data travelling across a computer network fail to reach their destination. Packet loss is either caused by errors in data transmission, typically across wireless networks, or network congestion.Kurose, J.F. & Ross, K.W. (2010). ''Computer Networking: A Top-Down Approach''. New York: Addison-Wesley. Packet loss is measured as a percentage of packets lost with respect to packets sent. The Transmission Control Protocol (TCP) detects packet loss and performs retransmissions to ensure reliable messaging. Packet loss in a TCP connection is also used to avoid congestion and thus produces an intentionally reduced throughput for the connection. In real-time applications like streaming media or online games, packet loss can affect a user's quality of experience (QoE). Causes The Internet Protocol (IP) is designed according to the end-to-end principle as a best-effort delivery service, with the intention of keeping the logic routers mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National University Of Sciences And Technology, Pakistan
The National University of Sciences & Technology (NUST) ( ur, , Qaumī Jāmi'ā barā'e Sāins va Ṭaiknālōjī) is a multi-campus public university, public research university having its main campus in Islamabad, Pakistan. The university offers undergraduate and graduate degrees, including doctoral and professional degrees. Founded in 1991, it was initially formed for the need of commissioned officers by combining engineering colleges and schools. Later, it was converted into a public research university with the main campus setup in Islamabad to promote Science, Technology, Engineering and Math, science and technology in Pakistan. Founded to provide quality technical education for rapid industrialization in Pakistan, NUST adopted an American university model and stressed laboratory instruction in applied science and engineering. It has since played a key role in the development of standardization in education of fields such as engineering, mathematics, and technology in Pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Centre For Theoretical Physics
The Abdus Salam International Centre for Theoretical Physics (ICTP) is an international research institute for physical and mathematical sciences that operates under a tripartite agreement between the Italian Government, United Nations Educational, Scientific and Cultural Organization (UNESCO), and International Atomic Energy Agency (IAEA). It is located near the Miramare Park, about 10 kilometres from the city of Trieste Trieste ( , ; sl, Trst ; german: Triest ) is a city and seaport in northeastern Italy. It is the capital city, and largest city, of the autonomous region of Friuli Venezia Giulia, one of two autonomous regions which are not subdivided into pr ..., Italy. The centre was founded in 1964 by Pakistani Nobel Laureate Abdus Salam. ICTP is part of the Trieste System, a network of national and international scientific institutes in Trieste, promoted by the Italian physicist Paolo Budinich. Mission * Foster the growth of advanced studies and research in phys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iperf
Iperf is a tool for network performance measurement and tuning. It is a Cross-platform software, cross-platform tool that can produce standardized performance measurements for any network. Iperf has Client (computing), client and Server (computing), server functionality, and can create data streams to measure the throughput between the two ends in one or both directions. Typical iperf output contains a time-stamped report of the amount of data transferred and the throughput measured. The data streams can be either Transmission Control Protocol (TCP) or User Datagram Protocol (UDP): * ''UDP'': When used for testing UDP capacity, iperf allows the user to specify the Datagram#Packets vs. datagrams, datagram size and provides results for the datagram throughput and the Packet (information technology), packet loss. * ''TCP'': When used for testing TCP capacity, iperf measures the throughput of the payload. Iperf uses 1024 × 1024 for mebibytes and 1000 × 1000 for megabytes. Iperf is o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Operations Center
A network operations center (NOC, pronounced like the word ''knock''), also known as a "network management center", is one or more locations from which network monitoring and control, or network management, is exercised over a computer, telecommunication or satellite network. __TOC__ History The earliest NOCs started during the 1960s. A Network Control Center was opened in New York by AT&T in 1962 which used status boards to display switch and routing information, in real-time, from AT&T's most important toll switches. AT&T later replaced this Network Control Center with a modernized NOC in 1977, located in Bedminster, New Jersey. Purpose NOCs are implemented by business organizations, public utilities, universities, and government agencies that oversee complex networking environments that require high availability. NOC personnel are responsible for monitoring one or many networks for certain conditions that may require special attention to avoid degraded service. Organiz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
