Teletraffic engineering , telecommunications traffic engineering , or just traffic engineering when in context, is the application of transportation traffic engineering theory to telecommunications . Teletraffic engineers use their knowledge of statistics including queuing theory , the nature of traffic, their practical models, their measurements and simulations to make predictions and to plan telecommunication networks such as a telephone network or the Internet . These tools and knowledge help provide reliable service at lower cost.
20-402: The field was created by the work of A. K. Erlang for circuit-switched networks but is applicable to packet-switched networks , as they both exhibit Markovian properties, and can hence be modeled by e.g. a Poisson arrival process. The crucial observation in traffic engineering is that in large systems the law of large numbers can be used to make the aggregate properties of a system over
40-525: A basic tariff system but, as telecommunication advances, tariff structures become increasingly more complex. Usually there is the option of calling collect (in the UK known as reversing charges ), where responsibility for charges normally paid by the caller is accepted by the recipient. Tariffs also depend on the bandwidth provided. For example, dial-up modem connections are charged at normal telephone costs, but connections such as DSL are usually charged using
60-496: A completely different accounting system due to their always on nature. Increasingly, in some countries, the call charges are fixed at a monthly rate and included as a supplement to the standing charges, known as inclusive calls . Emergency calls can invariably be made without charge. Most countries have a number sequence that enable the caller to make calls without charge, sometimes known as free calls or freephone , these are usually used by companies for their sales line (in
80-435: A long period of time much more predictable than the behaviour of individual parts of the system. The measurement of traffic in a public switched telephone network (PSTN) allows network operators to determine and maintain the quality of service (QoS) and in particular the grade of service (GoS) that they promise their subscribers. The performance of a network depends on whether all origin-destination pairs are receiving
100-399: A loss and the company will go bankrupt. Tariffs must also be used to cover maintenance , additional research and other indirect costs associated with providing the service. However, telecommunications service providers must be careful not to over-price each service, as prices have a direct influence on demand for that service (see supply and demand ). Such an operator must constantly balance
120-531: A satisfactory service. Networks are handled as: Congestion is defined as the situation when exchanges or circuit groups are inundated with calls and are unable to serve all the subscribers. Special attention must be given to ensure that such high loss situations do not arise. To help determine the probability of congestion occurring, operators should use the Erlang formulas or the Engset calculation . Exchanges in
140-474: A supporting network, it carries all the signalling messages necessary to set up, break down or provide extra services. The signalling enables the PSTN to control the manner in which traffic is routed from one location to another. Transmission and switching of calls is performed using the principle of time-division multiplexing (TDM). TDM allows multiple calls to be transmitted along the same physical path, reducing
160-471: Is noticeable, for both business and residential customers on international or local calls. This means that it is often the case that more revenue is achievable at lower prices, that is, E < -1. Internet traffic research show that the traffic intensity is directly affected by the tariffs charged in connecting customers to their Internet Service Provider (ISP). For example, a circuit-switched network provider charges different tariffs at different times of
180-454: Is the possibility that extremely infrequent occurrences are more likely than anticipated. This situation is known as long-tail traffic . In some designs, the network might be required to withstand the unanticipated traffic. As mentioned in the introduction, the purpose of teletraffic theory is to reduce cost in telecommunications networks. An important tool in achieving this goal is forecasting . Forecasting allows network operators to calculate
200-525: The Federal Communications Commission (FCC). Such tariffs outline the terms and conditions of providing telecommunications service to the public including rates, fees, and charges. At a minimum, tariffs imposed must cover the cost of providing the service to the consumer. The consumer may be the final user or an intermediary such as a service provider . If a telecommunications operator cannot recover its costs, it will make
220-542: The PSTN make use of trunking concepts to help minimize the cost of the equipment to the operator. Modern switches generally have full availability and do not make use of grading concepts. Overflow systems make use of alternative routing circuit groups or paths to transfer excess traffic and thereby reduce the possibility of congestion. A very important component in PSTNs is the SS7 network used to route signalling traffic. As
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#1732773352953240-540: The UK these are 0800 and 0808 numbers and in the US they are 800, 888, 877, 866, 855, 844 and 833). Tariffs substantially in excess of the normal rate, known as premium rate , are used for information services, competition entries and pornography calls. These telecommunications tariffs originated with the advent of public phone service. In these times, the services provided were less complex, and customers were able to simply read
260-576: The Wikimedia System Administrators, please include the details below. Request from 172.68.168.133 via cp1102 cp1102, Varnish XID 546108579 Upstream caches: cp1102 int Error: 429, Too Many Requests at Thu, 28 Nov 2024 05:55:53 GMT Tariffing A telecommunications tariff is an open contract between a telecommunications service provider and the public, filed with a regulating body such as state and municipal Public Utilities Commissions and federal entities such as
280-577: The cost of infrastructure. A good example of the use of teletraffic theory in practice is in the design and management of a call center . Call centers use teletraffic theory to increase the efficiency of their services and overall profitability through calculating how many operators are really needed at each time of the day. Queueing systems used in call centers have been studied as a science. For example, completed calls are put on hold and queued until they can be served by an operator. If callers are made to wait too long, they may lose patience and default from
300-409: The need to file tariffs with federal regulatory agencies. However, to continue operating, many state and local governments still require telecommunications tariffs. Call minutes are highly elastic against price , this means that the demand for call minutes varies greatly according to price. A slight decrease in price leads to a great increase in call minutes. The higher the price, the more this effect
320-667: The need to provide cheaper rates, especially if there is strong competition, with the cost of maintaining the service at an optimum quality that is acceptable to the customer. If an operator charges too much, it risks alienating its customers, resulting in a loss of traffic and therefore revenue; if they charge too little, they will have insufficient capital to maintain the network's quality of service . Over time this will result in customer attrition . Tariffing systems vary from country to country and company to company, but in general they are based on several simple principles. Tariffs are generally made up of two components: These components form
340-399: The potential cost of a new network / service for a given QoS during the planning and design stage, thereby ensuring that costs are kept to a minimum. An important method used in forecasting is simulation , which is described as the most common quantitative modelling technique in use today. An important reason for this is that computing power has become far more accessible, making simulation
360-598: The preferred analytical method for problems that are not easily solved mathematically. As in any business environment, network operators must charge tariffs for their services. These charges must be balanced with the supplied QoS. When operators supply services internationally, this is described as trade in services and is governed by the General Agreement on Trade in Services (GATS). Agner Krarup Erlang Too Many Requests If you report this error to
380-444: The queue (hang up), resulting in no service being provided. Teletraffic engineering is a well-understood discipline in the traditional voice network, where traffic patterns are established, growth rates can be predicted, and vast amounts of detailed historical data are available for analysis. However, in modern broadband networks , the teletraffic engineering methodologies used for voice networks are inappropriate. Of great importance
400-495: The tariffs to understand how much they would be charged for each type of call. Additionally, only a few telecommunication industries participated in the market, facilitating decision-making. As the market became increasingly competitive, the need for regulation decreased. In 2001, the U.S. Federal Communications Commission (FCC) declared the telecommunications market was fully competitive in the United States, and eliminated
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