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Routing In The PSTN
Routing in the PSTN is the process of forwarding telephone calls between the constituent telephone networks that comprise the public switched telephone network (PSTN). Telephone calls are routed across a network of potentially many switching systems, often owned by different telephone carriers. Switching systems are connected with trunks. Each switch may have many neighbors. Neighboring switches owned by different operators are connected at interconnect points. The PSTN is a network that uses destination routing to direct calls from origin to the recipient. It is not a full mesh network with the nodes of every operator directly connected to those of every other, which would be impractical and inefficient. Therefore, calls may be routed through intermediate operator networks before they reach their final destination. Efficient least-cost routing is an important procedure in PSTN routing. Call routing Each time a call is placed for routing, the destination number ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone
A telephone, colloquially referred to as a phone, is a telecommunications device that enables two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into electronic signals that are transmitted via Electrical cable, cables and other communication channels to another telephone which reproduces the sound to the receiving user. The term is derived from and (, ''voice''), together meaning ''distant voice''. In 1876, Alexander Graham Bell was the first to be granted a United States patent for a device that produced clearly intelligible replication of the human voice at a second device. This instrument was further developed by many others, and became rapidly indispensable in business, government, and in households. The essential elements of a telephone are a microphone (''transmitter'') to speak into and an earphone (''receiver'') which reproduces the voice a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-geographic Numbers
A non-geographic number is a type of telephone number that is not linked to any specific locality. Such numbers are an alternative to the traditional 'landline' numbers that are assigned geographically using a system of location-specific area codes. Non-geographic numbers are used for various reasons, from providing flexible routing of incoming phone calls to generating revenue for paid-for services. Functionality Non-geographic numbers were introduced to offer services that were historically unavailable on standard landline phone numbers, particularly in terms of call routing and special charging arrangements. Advertised benefits of non-geographic numbers include: * Call Routing. Calls can be flexibly redirected to virtually any destination. For example, calls could be answered in different call centres depending on where the caller is located or the time of day. * Ease of Communication. Organisations covering multiple locations can advertise a single national phone number rath ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frank Kelly (mathematician)
__NOTOC__ Francis Patrick Kelly, CBE, FRS (born 28 December 1950) is Professor of the Mathematics of Systems at the Statistical Laboratory, University of Cambridge. He served as Master of Christ's College, Cambridge from 2006 to 2016. Kelly's research interests are in random processes, networks and optimisation, especially in very large-scale systems such as telecommunication or transportation networks. In the 1980s, he worked with colleagues in Cambridge and at British Telecom's Research Labs on Dynamic Alternative Routing in telephone networks, which was implemented in BT's main digital telephone network. He has also worked on the economic theory of pricing to congestion control and fair resource allocation in the internet. From 2003 to 2006 he served as Chief Scientific Advisor to the United Kingdom Department for Transport. Kelly was elected a Fellow of the Royal Society in 1989. In December 2006 he was elected 37th Master of Christ's College, Cambridge. He was appoi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambridge University
The University of Cambridge is a Public university, public collegiate university, collegiate research university in Cambridge, England. Founded in 1209, the University of Cambridge is the List of oldest universities in continuous operation, world's third-oldest university in continuous operation. The university's founding followed the arrival of scholars who left the University of Oxford for Cambridge after a dispute with local townspeople. The two ancient university, ancient English universities, although sometimes described as rivals, share many common features and are often jointly referred to as Oxbridge. In 1231, 22 years after its founding, the university was recognised with a royal charter, granted by Henry III of England, King Henry III. The University of Cambridge includes colleges of the University of Cambridge, 31 semi-autonomous constituent colleges and List of institutions of the University of Cambridge#Schools, Faculties, and Departments, over 150 academic departm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Telecommunications
BT Group plc (formerly British Telecom) is a British multinational telecommunications holding company headquartered in London, England. It has operations in around 180 countries and is the largest provider of fixed-line, broadband and mobile services in the UK, and also provides subscription television and IT services. BT's origins date back to the founding in 1846 of the Electric Telegraph Company, the world's first public telegraph company, which developed a nationwide communications network. BT Group as it came to be started in 1912, when the General Post Office, a government department, took over the system of the National Telephone Company becoming the monopoly telecoms supplier in the United Kingdom. The Post Office Act of 1969 led to the GPO becoming a public corporation, Post Office Telecommunications. The ''British Telecom'' brand was introduced in 1980, and became independent of the Post Office in 1981, officially trading under the name. British Telecom was priv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plus Magazine
''Plus Magazine'' is an online popular mathematics magazine run under the Millennium Mathematics Project at the University of Cambridge. ''Plus'' contains: * feature articles on all aspects of mathematics; * reviews of popular maths books and events; * a news section; * mathematical puzzles and games; * interviews with people in maths related careers; * ''Plus'' Podcast – Maths on the Move History ''Plus'' was initially named PASS Maths (Public Awareness and Schools Support for Maths) in 1997, when it was a project of the Interactive Courseware Research and Development Group, based jointly at the University of Cambridge and Keele University. ''Plus'' is now part of the Millennium Mathematics Project, a long term national initiative based in Cambridge Cambridge ( ) is a List of cities in the United Kingdom, city and non-metropolitan district in the county of Cambridgeshire, England. It is the county town of Cambridgeshire and is located on the River Cam, north o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications Network
A telecommunications network is a group of Node (networking), nodes interconnected by telecommunications links that are used to exchange messages between the nodes. The links may use a variety of technologies based on the methodologies of circuit switching, message switching, or packet switching, to pass messages and signals. Multiple nodes may cooperate to pass the message from an originating node to the destination node, via multiple network hops. For this routing function, each node in the network is assigned a network address for identification and locating it on the network. The collection of addresses in the network is called the address space of the network. Examples of telecommunications networks include computer networks, the Internet, the public switched telephone network (PSTN), the global Telex network, the aeronautical ACARS network, and the wireless radio networks of cell phone telecommunication providers. Network structure this is the structure of network genera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Distance Dialing
Direct distance dialing (DDD) is a telecommunications service in North America by which a caller may call any other subscriber outside the local calling area without operator assistance, DDD was introduced in the United States in 1951, on a trial basis, with service from Englewood, New Jersey. Direct long-distance dialing by subscribers requires extra digits, called an area code, to be dialed as prefixes to the directory telephone number of the destination. International Direct Distance Dialing (IDDD) extends the system beyond the geographic boundaries of the North American Numbering Plan (NANP). History The first direct-dialed long-distance telephone calls were possible in the New Jersey communities of Englewood and Teaneck. Customers of the ENglewood 3, ENglewood 4 and TEaneck 7 exchanges, who could already dial telephone numbers in the New York City area, could place calls to eleven major cities across the United States by dialing the three-digit area code and the seven-di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flood Search Routing
In a telephone network, flood search routing is non-deterministic routing in which a dialed number received at a switch is transmitted to all switches, ''i.e.,'' flooded, in the area code directly connected to that switch; if the dialed number is not an affiliated subscriber at that switch, the number is then retransmitted to all directly connected switches, and then routed through the switch that has the dialed number corresponding to the particular User (telecommunications), user end instrument affiliated with it. All digits of the numbering plan are used to identify a particular subscriber. Flood search routing allows subscribers to have telephone numbers independent of switch codes. Flood search routing provides the highest probability that a telephone call will go through even though a number of switches and links fail. Flood search routing is used in military telecommunication systems, such as the mobile subscriber equipment (MSE) system. See also *Flooding (computer networkin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deterministic Routing
In telecommunications, deterministic routing is the advance determination of the routes between given pairs of nodes. Examples: #In a network where routing is controlled by a telephone switch or network switch, switching in which the routes between given pairs of nodes are pre-programmed, ''i.e.,'' are determined, in advance of transmission. The routes used to complete a given call through a network are identified, in advance of transmission, in routing tables maintained in each switch database. The tables assign the trunks that are to be used to reach each switch code, area code, and International Access Prefix (IAP), usually with one or two alternate routes. #In a non-switched network, the routes used to send a given message A message is a unit of communication that conveys information from a sender to a receiver. It can be transmitted through various forms, such as spoken or written words, signals, or electronic data, and can range from simple instructions to co ... through ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Area Code
A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, reachable by a system of destination code routing. Telephone numbering plans are defined world-wide, as well as within each of the administrative regions of the public switched telephone network (PSTN), and in private telephone networks. In public numbering systems, geographic location typically plays a role in the sequence of numbers assigned to each telephone subscriber. Many numbering plan administrators subdivide their territory of service into geographic regions designated by a prefix, often called an area code or city code, which is a set of digits forming the most-significant part of the dialing sequence to reach a telephone subscriber. Within such regions designated by area codes, locally unique telephone number are assigned based on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colocation (business)
Colocation (or co-location) is the act of placing multiple (sometimes related) entities within a single location. Examples * In an organization, it refers to placing related roles or groups in a single room, building or campus. * In business, it refers to the practice of locating multiple similar businesses in the same facility. * In trading, it often refers to placing multiple data centers in proximity to trading centers * In telecommunications, primarily wireless telecommunications facilities such as mobile wireless (cell sites) and radio broadcasting, it refers to the practice of locating multiple wireless broadcast facilities/providers within the same facility. Many jurisdictions now mandate the colocation of mobile wireless carriers within a single facility to avoid the proliferation of wireless communication towers. * In the fast food restaurant industry, one primary use of this concept is Yum! Brands with its KFC, Taco Bell, and Pizza Hut menus appearing in the same re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
