Measurement of traffic within a network allows network managers and analysts to both make day-to-day decisions about operations and to plan for long-term developments. [1] [2] Traffic Measurements are used in many fundamental activities such as: [2]
The following sections will answer some fundamental questions about Traffic Measurement, such as: What should be measured; when should it be measured; what assumptions are made; and what errors can occur?
Traffic Measurements are conducted on a continuous basis and the results compiled into reports for management which are used in management decisions on various time scales. Measurements that are taken every few minutes are used for network management and temporary routing, measurements every few hours, days and weeks are used for maintenance purposes and measurements that are taken over months or even years are used for long-term network deployment, upgrading and extensions. [2]
To determine normal reference traffic for a network, the ITU recommends that a network traffic analyst must take measurements for the busiest hour of each day for a whole year. [2] The busiest hour is defined as that four consecutive quarter hours whose traffic intensity is the greatest. Measurements taken outside the busy hour can be discarded. The reference intensity of traffic is then calculated by taking the average traffic intensity of the top thirty days in the year. [2] Measurements taken on individual days can be discarded. This will give the normal high traffic intensity in the network, allowing network managers to make long-term strategic decisions. [2]
To perform calculations in circuit-switched networks several assumptions are made: [3]
It is useful to remember that the measurements are averages, and this process deliberately ignores very short term variations in the traffic, but still allows for a small but finite loss. The above assumptions are accurate if applied to circuit switched networks; however they fail when planning for data traffic, small exchanges and sudden sharp peaks in traffic such as that caused by TV and radio phone-in competitions.
Measurement errors are caused by faults in equipment or constraints on equipment design. The following five errors are examples of some types of errors that can occur: [2]
The erlang is a dimensionless unit that is used in telephony as a measure of offered load or carried load on service-providing elements such as telephone circuits or telephone switching equipment. A single cord circuit has the capacity to be used for 60 minutes in one hour. Full utilization of that capacity, 60 minutes of traffic, constitutes 1 erlang.
Network throughput 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, and sometimes in data packets per second or data packets per time slot.
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Network traffic simulation is a process used in telecommunications engineering to measure the efficiency of a communications network.
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A wind power forecast corresponds to an estimate of the expected production of one or more wind turbines in the near future, up to a year. Forecast are usually expressed in terms of the available power of the wind farm, occasionally in units of energy, indicating the power production potential over a time interval.
Network traffic or data traffic is the amount of data moving across a network at a given point of time. Network data in computer networks is mostly encapsulated in network packets, which provide the load in the network. Network traffic is the main component for network traffic measurement, network traffic control and simulation.
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Industrial process data validation and reconciliation, or more briefly, process data reconciliation (PDR), is a technology that uses process information and mathematical methods in order to automatically ensure data validation and reconciliation by correcting measurements in industrial processes. The use of PDR allows for extracting accurate and reliable information about the state of industry processes from raw measurement data and produces a single consistent set of data representing the most likely process operation.
ITU-T Y.156sam Ethernet Service Activation Test Methodology is a draft recommendation under study by the ITU-T describing a new testing methodology adapted to the multiservice reality of packet-based networks.
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