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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 (a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telephone
A telephone is a telecommunications device that permits 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 cables and other communication channels to another telephone which reproduces the sound to the receiving user. The term is derived from el, τῆλε (''tēle'', ''far'') and φωνή (''phōnē'', ''voice''), together meaning ''distant voice''. A common short form of the term is ''phone'', which came into use early in the telephone's history. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intelligent Network
The Intelligent Network (IN) is the standard network architecture specified in the ITU-T Q.1200 series recommendations. It is intended for fixed as well as Global System for Mobile Communications, mobile telecommunication, telecom networks. It allows operators to differentiate themselves by providing value-added services in addition to the standard telecom services such as PSTN, ISDN on fixed networks, and GSM services on Mobile phone, mobile phones or other mobile devices. The intelligence is provided by network nodes on the service layer, distinct from the telephone exchange, switching layer of the core network, as opposed to solutions based on intelligence in the core telephone exchange, switches or equipment. The IN nodes are typically owned by telecommunications service providers such as a telephone company or mobile phone operator. IN is supported by the Signaling System 7, Signaling System #7 (SS7) protocol between network switching centers and other network nodes owned by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Statistical Laboratory, University Of Cambridge
The Faculty of Mathematics at the University of Cambridge comprises the Department of Pure Mathematics and Mathematical Statistics (DPMMS) and the Department of Applied Mathematics and Theoretical Physics (DAMTP). It is housed in the Centre for Mathematical Sciences site in West Cambridge, alongside the Isaac Newton Institute. Many distinguished mathematicians have been members of the faculty. Some current members DPMMS *Béla Bollobás * John Coates * Thomas Forster *Timothy Gowers * Peter Johnstone *Imre Leader *Gabriel Paternain Statistical Laboratory * John Aston *Geoffrey Grimmett *Frank Kelly *Ioannis Kontoyiannis *Richard Nickl * James Norris *Richard Samworth *David Spiegelhalter * Richard Weber DAMTP *Gary Gibbons * Julia Gog, professor of mathematical biology * Raymond E. Goldstein *Rich Kerswell *Paul Linden * Michael Green * Peter Haynes, fluid dynamicist * John Hinch, fluid dynamicist, retired 2014 *Richard Jozsa *Hugh Osborn *John Papaloizou * Malcolm Perry * D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BT Research
BT Research is the research arm of BT Group, formerly part of the British Post Office. The company was first established in 1921 as the Post Office Research Station at Dollis Hill, London. In 1968 BT moved of its research to the new site at Martlesham Heath based on part of the old Royal Air Force Station at Martlesham Heath near Ipswich in the English county of Suffolk, which was later renamed Adastral Park. __TOC__ Location BT's main research facility is located in the United Kingdom at Adastral Park, near Ipswich in the county of Suffolk. The Adastral Park site was first planned around 1968 as the Martlesham Heath Post Office Laboratories and after completion in 1971 has grown since then to a facility today which has around 4,000 research and development people from both BT and some of its partner companies. Globally, BT has additional research labs in Beijing, Boston MA and Abu Dhabi. The focus of research at BT is Information and Communications Technology (ICT). The Ro ... [...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
, mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Scholars of the University of Cambridge , type = Public research university , endowment = £7.121 billion (including colleges) , budget = £2.308 billion (excluding colleges) , chancellor = The Lord Sainsbury of Turville , vice_chancellor = Anthony Freeling , students = 24,450 (2020) , undergrad = 12,850 (2020) , postgrad = 11,600 (2020) , city = Cambridge , country = England , campus_type = , sporting_affiliations = The Sporting Blue , colours = Cambridge Blue , website = , logo = University of Cambridge logo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
British Telecommunications
BT Group plc (trading as BT and 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. The ''British Telecom'' brand was introduced in 1980, and became independent of the Post Office in 1981, officially trading under the name. British Telecommunications was privatised ... [...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 and active across the UK and internationally. Authors of articles in ''Plus'' include Stephen Hawking and Marcus du Sautoy. ''Plus'' won the 2001 Webby for ''Best Science Site on the Web'', and has been described as "an e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications Network
A telecommunications network is a group of 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 In general, every telecommunications network conceptually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Distance Dialing
Direct distance dialing (DDD) is a telecommunication service feature in North America by which a caller may, without operator assistance, call any other user outside the local calling area. Direct dialing by subscribers typically requires extra digits 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-digit directory number. Local telephone numbers still consisted of the first two letters of the central office name and five digits. On ... [...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 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 networking) Flooding is used ... [...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 discrete unit of communication intended by the source for consumption by some recipient or group of recipients. A message may be delivered by various means, including courier, telegraphy, carrier pigeon and electronic bus. A ... through ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
