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Burstable
Burstable billing is a method of measuring bandwidth based on peak use. It allows usage to exceed a specified threshold for brief periods of time without the financial penalty of purchasing a higher committed information rate (CIR, or ''commitment'') from an Internet service provider (ISP). Most ISPs use a five-minute sampling and 95% usage when calculating usage. 95th percentile The 95th percentile is a widely used mathematical calculation to evaluate the regular and sustained use of a network connection. The 95th percentile method more closely reflects the ''needed capacity'' of the link in question than tracking by other methods such as mean or maximum rate. The bytes that make up the packets themselves do not actually cost money, but the link and the infrastructure on either end of the link cost money to set up and support. This method of billing is commonly used in peering arrangements between corporate networks; it is not often used by ISPs because such entities need commi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Committed Information Rate
In a Frame Relay network, committed information rate (CIR) is the bandwidth for a virtual circuit guaranteed by an internet service provider to work under normal conditions. Committed data rate (CDR) is the payload portion of the CIR. At any given time, the available bandwidth ''should not'' fall below this committed figure. The bandwidth is usually expressed in kilobits per second (kbit/s). Above the CIR, an allowance of burstable bandwidth is often given, whose value can be expressed in terms of an additional rate, known as the excess information rate (EIR), or as its absolute value, peak information rate (PIR). The provider guarantees that the connection will always support the CIR rate, and sometimes the EIR rate provided that there is adequate bandwidth. The PIR, i.e. the CIR plus EIR, is either equal to or less than the speed of the access port into the network. Frame Relay carriers define and package CIRs differently, and CIRs are adjusted with experience. See also * In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Percentile
In statistics, a ''k''-th percentile (percentile score or centile) is a score ''below which'' a given percentage ''k'' of scores in its frequency distribution falls (exclusive definition) or a score ''at or below which'' a given percentage falls (inclusive definition). For example, the 50th percentile (the median) is the score below which 50% of the scores in the distribution are found (by the "exclusive" definition), or at or below which 50% of the scores are found (by the "inclusive" definition). Percentiles are expressed in the same unit of measurement as the input scores; for example, if the scores refer to human weight, the corresponding percentiles will be expressed in kilograms or pounds. The percentile score and the '' percentile rank'' are related terms. The percentile rank of a score is the percentage of scores in its distribution that are less than it, an exclusive definition, and one that can be expressed with a single, simple formula. Percentile scores and perce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bandwidth (computing)
In computing, bandwidth is the maximum rate of data transfer across a given path. Bandwidth may be characterized as network bandwidth, data bandwidth, or digital bandwidth. This definition of ''bandwidth'' is in contrast to the field of signal processing, wireless communications, modem data transmission, digital communications, and electronics, in which ''bandwidth'' is used to refer to analog signal bandwidth measured in hertz, meaning the frequency range between lowest and highest attainable frequency while meeting a well-defined impairment level in signal power. The actual bit rate that can be achieved depends not only on the signal bandwidth but also on the noise on the channel. Network capacity The term ''bandwidth'' sometimes defines the net bit rate 'peak bit rate', 'information rate,' or physical layer 'useful bit rate', channel capacity, or the maximum throughput of a logical or physical communication path in a digital communication system. For example, bandwidth test ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RRDtool
RRDtool (''round-robin database tool'') aims to handle time series data such as network bandwidth, temperatures or CPU load. The data is stored in a circular buffer based database, thus the system storage footprint remains constant over time. It also includes tools to extract round-robin data in a graphical format, for which it was originally intended. Bindings exist for several programming languages, e.g. Perl, Python, Ruby, Tcl, PHP and Lua. There is an independent full Java implementation called rrd4j. General data storage RRDtool assumes time-variable data in intervals of a certain length. This interval, usually named step, is specified upon creation of an RRD file and cannot be changed afterwards. Because data may not always be available at just the right time, RRDtool will automatically interpolate any submitted data to fit its internal time-steps. The value for a specific step, that has been interpolated, is named a primary data point (PDP). Multiple PDPs may be consoli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cacti (software)
Cacti is an open-source, web-based network monitoring and graphing tool designed as a front-end application for the open-source, industry-standard data logging tool RRDtool. Cacti allows a user to poll services at predetermined intervals and graph the resulting data. It is generally used to graph time-series data of metrics such as CPU load and network bandwidth utilization. A common usage is to monitor network traffic by polling a network switch or router interface via Simple Network Management Protocol (SNMP). The front end can handle multiple users, each with their own graph sets, so it is sometimes used by web hosting providers (especially dedicated server, virtual private server, and colocation providers) to display bandwidth statistics for their customers. It can be used to configure the data collection itself, allowing certain setups to be monitored without any manual configuration of RRDtool. Cacti can be extended to monitor any source via shell scripts and executabl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patch (computing)
A patch is a set of changes to a computer program or its supporting data designed to update, fix, or improve it. This includes fixing security vulnerabilities and other bugs, with such patches usually being called bugfixes or bug fixes. Patches are often written to improve the functionality, usability, or performance of a program. The majority of patches are provided by software vendors for operating system and application updates. Patches may be installed either under programmed control or by a human programmer using an editing tool or a debugger. They may be applied to program files on a storage device, or in computer memory. Patches may be permanent (until patched again) or temporary. Patching makes possible the modification of compiled and machine language object programs when the source code is unavailable. This demands a thorough understanding of the inner workings of the object code by the person creating the patch, which is difficult without close study of the sourc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multi Router Traffic Grapher
The Multi Router Traffic Grapher (MRTG) is free software for monitoring and measuring the traffic load on network links. It allows the user to see traffic load on a network over time in graphical form. It was originally developed by Tobias Oetiker and Dave Rand to monitor router traffic, but has developed into a tool that can create graphs and statistics for almost anything. MRTG is written in Perl and can run on Windows, Linux, Unix, Mac OS and NetWare. How it works SNMP MRTG uses the Simple Network Management Protocol (SNMP) to send requests with two object identifiers (OIDs) to a device. The device, which must be SNMP-enabled, will have a management information base (MIB) to look up the OIDs specified. After collecting the information it will send back the raw data encapsulated in an SNMP protocol. MRTG records this data in a log on the client along with previously recorded data for the device. The software then creates an HTML document from the logs, containing a list of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sample (statistics)
In statistics, quality assurance, and survey methodology, sampling is the selection of a subset (a statistical sample) of individuals from within a statistical population to estimate characteristics of the whole population. Statisticians attempt to collect samples that are representative of the population in question. Sampling has lower costs and faster data collection than measuring the entire population and can provide insights in cases where it is infeasible to measure an entire population. Each observation measures one or more properties (such as weight, location, colour or mass) of independent objects or individuals. In survey sampling, weights can be applied to the data to adjust for the sample design, particularly in stratified sampling. Results from probability theory and statistical theory are employed to guide the practice. In business and medical research, sampling is widely used for gathering information about a population. Acceptance sampling is used to determine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Throughput
Network throughput (or just throughput, when in context) refers to the rate of message delivery over a communication channel, such as Ethernet or packet radio, in a communication network. The data that these messages contain may be delivered over physical or logical links, or through network nodes. Throughput is usually measured in bits per second (bit/s or bps), and sometimes in data packets per second (p/s or pps) or data packets per time slot. The system throughput or aggregate throughput is the sum of the data rates that are delivered to all terminals in a network. Throughput is essentially synonymous to digital bandwidth consumption; it can be determined numerically by applying the queueing theory, where the load in packets per time unit is denoted as the arrival rate (), and the drop in packets per unit time is denoted as the departure rate (). The throughput of a communication system may be affected by various factors, including the limitations of the underlying analog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bit Rate
In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time. The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction with an SI prefix such as kilo (1 kbit/s = 1,000 bit/s), mega (1 Mbit/s = 1,000 kbit/s), giga (1 Gbit/s = 1,000 Mbit/s) or tera (1 Tbit/s = 1,000 Gbit/s). The non-standard abbreviation bps is often used to replace the standard symbol bit/s, so that, for example, 1 Mbps is used to mean one million bits per second. In most computing and digital communication environments, one byte per second (symbol: B/s) corresponds to 8 bit/s. Prefixes When quantifying large or small bit rates, SI prefixes (also known as metric prefixes or decimal prefixes) are used, thus: Binary prefixes are sometimes used for bit rates. The International Standard ( IEC 80000-13) specifies different a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
