A wireless personal area network (PAN) technology . Bluetooth is a computing and telecommunications industry specification that describes how mobile phones, computers, and personal digital assistants (PDAs) can easily interconnect with each other and with home and business phones and computers using a short-range wireless connection. Bluetooth is an open standard for short-range transmission of digital voice and data between mobile devices (laptops, PDAs, phones) and desktop devices. It supports point-to-point and multipoint applications Bluetooth is a low power radio technology being developed with the objective of replacing the wires currently used to connect electronic devices such as personal computers, printers and a wide variety of handheld devices such as palm top computers and mobile phones. Using this technology, users of cellular phones, pagers, and personal digital assistants such as the PalmPilot will be able to buy a three-in-one phone that can double as a portable phone at home or in the office, get quickly synchronised with information in a desktop or notebook computer, initiate the sending or receiving of a fax, initiate a print-out, and, in general, have all mobile and fixed computer devices be totally co-ordinated. Devices equipped with Bluetooth should be capable of exchanging data at speeds up to 720kbit/s within a range of 10 metres and up to 100 meters with a power boost. Data can be exchanged at a rate of 1 megabits per second (up to 2 Mbps in the second generation of the technology). In addition to data, up to three voice channels are available. Each device has a unique 48-bit address from the IEEE 802 standard. Connections can be point-to-point or multipoint. The maximum range is 10 meters.
Technology that uses a type of short-wave analogue or digital transmission in which a subscriber has a wireless connection from a mobile telephone to a relatively nearby transmitter. The transmitter's span of coverage is called a cell. Generally, cellular telephone service is available in urban areas and along major highways. As the cellular telephone user moves from one cell or area of coverage to another, the telephone is effectively passed on to the local cell transmitter. See Wireless
CDMA Code Division Multiple Access The principle of CDMA is that individual signals (e.g. a telecommunications conversation) are each coded with a unique algorithm, and then all transmitted simultaneously across a wide frequency band at very low power. The low power transmission does not attempt to overcome channel "noise" or interference. The receiver identifies the incoming signal by recognising the algorithm code applied by the transmitter, and separates the signal from background noise and other signals transmitted on the same frequency. See TDMA
The combining of computer networks with telephone networks and television, enabling organisations to communicate over a single network. Software enables computer networks and telephone networks to work together.
DTAP Direct Transfer Application Part Is used to transfer call control and mobility management messages between the MSC and the MS. The DTAP information in these messages is not interpreted by the BSS. Messages received from the MS are identified as DTAP by the Protocol Discriminator Information Element. The majority of radio interface messages are transferred across the BSS MSC interface by DTAP, except for messages belonging to the Radio Resource (RR) management protocol. The DTAP function is in charge of transferring layer 3 messages from the MS (or from the MSC) to the MSC (or to the MS) without any analysis of the message contents. The interworking between the layer 2 protocol on the radio side and signalling system 7 at the landside is based on the use of individual SCCP connections for each MS and on the distribution function.
EDGE Enhanced Data rates for GSM Environment An enhancement to the Global System for Mobile (GSM) and TDMA wireless service, a communications system that is designed to increases data throughput at rates up to 384 Kbps and enable the delivery of multimedia and other broadband applications to mobile phone and computer users. The EDGE standard uses a new modulation schema to enable data throughput speeds of up to 384kbit/s using existing GSM standard infrastructure and using the same time-division multiple access (TDMA) frame structure and existing cell arrangements. As 384kbit/s is the data speed being offered in the first phase of third generation deployment, EDGE could offer an alternative route for GSM operators who will not have third generation licences. EDGE, which is currently being standardised within the European Telecommunications Standards Institute (ETSI), represents the final evolution of data communications within the GSM standard. EDGE is expected to be commercially available in 2001. It is regarded as an evolutionary standard on the way to Universal Mobile Telecommunications Service (UMTS). See GSM, UMTS and TDMA GPRS General Packet Radio Service GPRS, which has been standardised by ETSI as part of the GSM Phase 2+ development, is essentially a circuit switched technology. An enhancement to the GSM mobile communications system that supports data packets. GPRS enables continuous flows of IP data packets over the system for such applications as Web browsing and file transfer. It is a packet-based wireless communication service that promises data rates from 56 up to 114 Kbps and continuous connection to the Internet for mobile phone and computer users. GPRS is based on Global System for Mobile (GSM) communication and will complement existing services such circuit-switched cellular phone connections and the Short Message Service (SMS). GPRS differs from GSM's short messaging service (GSM-SMS) which is limited to messages of 160 bytes in length. GPRS allows GSM networks to be truly compatible with the Internet. GPRS uses a packet-mode technique to transfer bursty traffic in an efficient manner. The two key benefits of GPRS are a better use of radio and network resources and completely transparent IP support. Once GPRS becomes available, mobile users of a virtual private network (VPN) will be able to access the private network continuously rather than through a dial-up connection. GPRS is an evolutionary step toward Enhanced Data GSM Environment (EDGE) and Universal Mobile Telephone Service (UMTS). See GSM, SS7, Cellular, SMS, Bluetooth and GSM.
GSM Global System for Mobile Communications GSM is the de facto wireless telephone standard in Europe. Developed in the 1980s, GSM was first deployed in seven European countries in 1991. GSM has over 250 million users worldwide and is now available in over 127 countries. Most many GSM network operators have roaming agreements with foreign operators, users can often continue to use their mobile phones when they travel to other countries. A digital cellular mobile phone technology based on TDMA that is the predominant system in Europe, but is also used around the world, it is the most widely used of the three digital wireless telephone technologies (GSM, TDMA, and CDMA). GSM digitises and compresses data, then sends it down a channel with two other streams of user data, each in its own time slot. It operates at either the 900 or 1800 MHz frequency band (in most of the world) a 1900 MHz band is supported (in the U.S). GSM defines the entire cellular system, not just the air interface (TDMA, CDMA, etc.). GSM phones use a Subscriber Identity Module (SIM) smart card that contains user account information. GSM provides a short messaging service (SMS) that enables text messages up to 160 characters in length to be sent to and from a GSM phone. It also supports data transfer at 9.6 Kbps to packet networks, ISDN and POTS users. GSM is a circuit-switched system that divides each 200KHz channel into eight 25KHz-time slots. See GPRS, EDGE, HSCSD, GSM, TDMA and CDMA .
A specification defining how voice, video, and data traffic will be transported on the Internet . H.323 is a protocol for the transmission of real-time audio, video and data information over packet switching-based networks, including Internet telephony. An ITU standard for real-time, interactive voice and videoconferencing over LANs and the Internet. H.323 specifies several video codecs, including H.261 and H.263, and audio codecs, including G.711 and G.723.1. Gateways, gatekeepers and multipoint control units (MCUs) are also covered. See MGCP.
HSCSD High Speed Circuit Switched Data A circuit-switched wireless data transmission for mobile users at data rates up to 38.4 Kbps, four times faster than the standard data rates of the Global System for Mobile (GSM) communication standard in 1999, and comparable to the speed of many computer modems communicating with fixed telephone networks. It is a part way link to Universal Mobile Telecommunications Service (UMTS). See GSM and UMTS
HTML HyperText Markup Language A script language used to describe the text content and format of a Web Page. It includes simple directives (called tags) which indicate the style of headings and content text, and select other features such as pictures or Java programs. The interpretation of the script language is highly dependent on the web browser used, the size of the screen and user preferences, which mean that the same HTML script rarely looks the same on any two computers.
HTTP HyperText Transfer Protocol http is the computer handshaking protocol used between a Web Browser and a Web Server to request and receive a web page. The protocol operates over IP.
The IP part of the TCP/IP communications protocol. The Internet Protocol (IP) is the method or protocol by which data is sent from one computer to another on the Internet. IP is a protocol used for the transmission of information, primarily between computers over the Internet. IP implements the network layer (layer 3) of the protocol, which contains a network address and is used to route a message to a different network or subnetwork. IP accepts "packets" from the layer 4 transport protocol (TCP or UDP), adds its own header to it and delivers a "datagram" to the layer 2 data link protocol. It may also break the packet into fragments to support the maximum transmission unit (MTU) of the network. All computers with Internet access are given a unique address consisting of four numbers separated by dots. IP Version 6 (IPv6) is beginning to be supported. IPv6 provides for much longer addresses and therefore for the possibility of many more Internet users. IPv6 includes the capabilities of IPv4 and any server that can support IPv6 packets can also support IPv4 packets. See TCP/IP, IP.
IPv6 Internet Protocol Version 6 IP version 6 (IPv6) is a new version of the Internet Protocol based on IPv4. IPv4 and IPv6 are demultiplexed at the media layer. For example, IPv6 packets are carried over Ethernet with the content type 86DD (hexadecimal) instead of IPv4's 0800. IPv6 (Internet Protocol Version 6) is the latest level of the Internet Protocol (IP) and is now included as part of IP support in many products including the major computer operating systems. IPv6 has also been called "IPng" (IP Next Generation). Formally, IPv6 is a set of specifications from the Internet Engineering Task Force (IETF). IPv6 was designed as an evolutionary set of improvements to the current IP Version 4. Network hosts and intermediate nodes with either IPv4 or IPv6 can handle packets formatted for either level of the Internet Protocol. Users and service providers can update to IPv6 independently without having to co-ordinate with each other. The next generation IP protocol. Started in 1991, the specification was completed in 1997 by the Internet Engineering Task Force (IETF). IPv6 is backward compatible with and is designed to fix the shortcomings of IPv4, such as data security and maximum number of user addresses. IPv6 increases the address space from 32 to 128 bits, providing for an unlimited (for all intents and purposes) number of networks and systems. IPv6 increases the IP address size from 32 bits to 128 bits, to support more levels of addressing hierarchy, a much greater number of addressable nodes and simpler auto-configuration of addresses. The most obvious improvement in IPv6 over the IPv4 is that IP addresses are lengthened from 32 bits to 128 bits. This extension anticipates considerable future growth of the Internet and provides relief for what was perceived as an impending shortage of network addresses. IPv6 describes rules for three types of addressing: unicast (one host to one other host), anycast (one host to the nearest of multiple hosts), and multicast (one host to multiple hosts). Additional advantages of IPv6 are: Options are specified in an extension to the header that is examined only at the destination, thus speeding up overall network performance. The introduction of an "anycast" address provides the possibility of sending a message to the nearest of several possible gateway hosts with the idea that any one of them can manage the forwarding of the packet to others. Anycast messages can be used to update routing tables along the line. Packets can be identified as belonging to a particular "flow" so that packets that are part of a multimedia presentation that needs to arrive in "real time" can be provided a higher quality-of-service relative to other customers. Improved support for extensions and options - IPv6 options are placed in separate headers that are located between the IPv6 header and the transport layer header. Changes in the way IP header options are encoded allow more efficient forwarding, less stringent limits on the length of options, and greater flexibility for introducing new options in the future. The extension headers are: Hop-by-Hop Option, Routing (Type 0), Fragment, Destination Option, Authentication, and Encapsulation Payload. The IPv6 header now includes extensions that allow a packet to specify a mechanism for authenticating its origin, for ensuring data integrity, and for ensuring privacy. It also supports quality of service (QoS) parameters for real-time audio and video. The draft version of IPv6 was originally called "IP Next Generation" (IPng). Flow labelling capability - A new capability has been added to enable the labelling of packets belonging to particular traffic flows for which the sender requests special handling, such as non-default Quality of Service or real-time service. Scalability of multicast addresses is introduced. A new type of address called an anycast address is also defined, to send a packet to any one of a group of nodes.
IPDC Internet Protocol Device Control A protocol for controlling media gateways developed by the Technical Advisory Committee, which was convened by Level 3 and others. It analyses incoming data signals, in band control signals and tones and sets up and controls the appropriate gateways. It also handles management and reporting.
An IP telephony protocol that is a combination of the MGCP and IPDC protocols. It is simpler than H.323. See MGCP, IPDC and H.323.
MGCP Media Gateway Control Protocol A protocol for IP telephony from the IETF. Working in conjunction with the Gateway Location Protocol (GLP), it enables a caller with a PSTN phone number to locate the destination device and establish a session. It provides the gateway-to-gateway interface for the Session Initialisation Protocol (SIP). SIP is a less-complex alternative to the H.323 protocol. See SIP and GLP..
An IP enhancement that provides forwarding of traffic to moving users. It uses agents in the user's home network and in all foreign networks. When logging on to a remote network, users register their presence with the foreign agent, and the home agent forwards the packets to the remote network. Mobile IP enables nodes to move from one IP subnet to another. Each mobile node is always identified by its home address, regardless of its current point of attachment to the Internet. While situated away from its home, a mobile node is also associated with a care-of address, which provides information about its current point of attachment to the Internet. The protocol allows registration of the care-of address with a home agent. The home agent sends datagrams destined for the mobile node through a tunnel to the care- of address. After arriving at the end of the tunnel, each datagram is then delivered to the mobile node. It can be used for mobility across both homogeneous and heterogeneous media. Mobile IP defines a set of new control messages, sent with UDP, Registration Request and Registration Reply. The IP packet consists of the IP source address and IP destination address, followed by the UDP source port and destination port followed by the Mobile IP fields. Mobile IP packets can be either Registration Request or Registration Reply. See IP.
MPLS MultiProtocol Label Switching A set of procedures for augmenting network layer packets with "label stacks", thereby turning them into labelled packets. A standards-approved technology for speeding up network traffic flow and making it easier to manage. MPLS involves setting up a specific path for a given sequence of packets, identified by a label put in each packet, thus saving the time needed for a router to look up the address to the next node to forward the packet to. MPLS is called multiprotocol because it works with the Internet Protocol (IP), Asynchronous Transport Mode (ATM), and frame relay network protocols. With reference to the standard model for a network (the Open Systems Interconnection, or OSI model), MPLS allows most packets to be forwarded at the layer 2 (switching) level rather than at the layer 3 (routing) level. Similar to Cisco's tag switching, MPLS uses labels, or tags, that contain forwarding information, which are attached to IP packets by a router that sits at the edge of the network known as a label edge router (LER). The routers in the core of the network, known as label switch routers (LSRs), examine the label more quickly than if they had to look up destination addresses in a routing table. In addition to moving traffic faster overall, MPLS makes it easy to manage a network for quality of service (QoS). For these reasons, the technique is expected to be readily adopted as networks begin to carry more and different mixtures of traffic. When fully implemented on the Internet, MPLS is expected to deliver the quality of service (QoS) required to adequately support real-time voice and video as well as service level agreements (SLAs) that guarantee bandwidth. Following in the tradition of the "dumb network," MPLS enables more decisions to be made at the periphery of the network. See IP and QoS.
On the Internet and in other networks, QoS (Quality of Service) is the idea that transmission rates, error rates, and other characteristics can be measured, improved, and, to some extent, guaranteed in advance. QoS is of particular concern for the continuous transmission of high-bandwidth video and multimedia information. Transmitting this kind of content dependably is difficult in public networks using ordinary "best effort" protocols. Using the Internet's Resource Reservation Protocol (RSVP), packets passing through a gateway host can be expedited based on policy and reservation criteria arranged in advance. In ATM, for example, which also lets a company or user preselect a level of quality in terms of service, QoS can be measured and guaranteed in terms of the average delay at a gateway, the variation in delay in a group of cells (cells are 53-byte transmission units), cell losses, and the transmission error rate.
The successor to SLIP, a TCP/IP protocol that provides host-to-network and router-to-router connections over both synchronous and asynchronous circuits. Can be used to provide a serial line connection between two machines, typically a personal computer connected by phone line to a server. See SLIP.
A protocol is the special set of rules for communicating that the end points in a telecommunication connection use when they send signals back and forth. Protocols exist at several levels in a telecommunication connection. There are hardware telephone protocols. There are protocols between the end points in communicating programs within the same computer or at different locations. Both end points must recognise and observe the protocol. Protocols are often described in an industry or international standard.
SIP Session Initiation Protocol A protocol that provides telephony services similar to H.323, but is less complex and uses fewer resources, making it suitable for very small portable devices. See H.323 and MGCP.
SLIP Serial Line Internet Protocol An Internet protocol used to utilise TCP/IP for communication between two machines over serial lines, that are previously configured for communication with each other. A better service is provided by the Point-to-Point Protocol (PPP). See PPP.
SMDS Switched Multimegabit Data Service A high-speed, switched data communications service offered by the local telephone companies for interconnecting LANs in different locations. It was introduced in 1992 and became generally available nation-wide by 1995. Connection to an SMDS service can be made from a variety of devices, including bridges, routers, CSU/DSUs as well as via frame relay and ATM networks. SMDS can employ various networking technologies. Data is framed for transmission using the SMDS Interface Protocol , which packages data as Level 3 Protocol Data Units (L3_PDU). The L3_PDU contains source and destination addresses and a data field that holds up to 9188 bytes. See SMDS-IP
SMDS IP SMDS Interface Protocol Three-level protocol that controls access to the network. The protocol used to support SMDS service. It is composed of the Level 3 Protocol Data Unit (L3_PDU), which contains source and destination addresses and an information field up to 9188 bytes long. See SMDS.
A text message service that enables short messages of generally no more than 140-160 characters in length to be sent and transmitted from a cellphone. SMS is supported by GSM and other mobile communications systems. Unlike paging, short messages are stored and forwarded in SMS centres. In the GSM system, short messages ride on a separate signalling path so they are transmitted simultaneously with voice, data and fax. See GSM
SMTP Simple Mail Transfer Protocol The basic TCP/IP application protocol used in sending and receiving e-mail services.
A common channel signalling system. The protocol used in the public switched telephone system (the "intelligent network" or "advanced intelligent network") for setting up calls and providing services. SS7 is a separate signalling network that is used in Class 4 and Class 5 voice switches. The SS7 network sets up and tears down the call, handles all the routing decisions and supports all modern telephony services such as 800 numbers, call forwarding, caller ID and local number portability (LNP). The voice switches known as "service switching points" (SSPs) query "service control point" (SCP) databases using packet switches known as "signal transfer points" (STPs). Accessing databases using a separate signalling network enables the system to more efficiently obtain static information such as the services a customer has signed up for and dynamic information such as ever-changing traffic conditions in the network. In addition, a voice circuit is not tied up until a connection is actually made between both parties. There is an international version of SS7 standardised by the ITU, and national versions determined by each country.
TCP Transmission Control Protocol IETF RFC793 defines the Transmission Control Protocol (TCP). TCP provides a reliable stream delivery and virtual connection service to applications through the use of sequenced acknowledgement with retransmission of packets when necessary.
Originally developed to interconnect various defence department computer networks. The Internet, an international Wide Area Network, uses TCP/IP to connect government and educational institutions, commercial and private networks across the world.
TCP/IP Transmission Control Protocol/Internet Protocol The basic communication language or protocol of the Internet and private networks called intranets and in extranets. When set up with direct access to the Internet, your computer is provided with a copy of the TCP/IP program just as the computer that you may send messages to or get information from also has a copy of TCP/IP. TCP/IP is a two-layered program. The higher layer, Transmission Control Protocol, manages the assembling of a message or file into smaller packets that are transmitted over the Internet and received by a TCP layer that reassembles the packets into the original message. The lower layer, Internet Protocol, handles the address part of each packet so that it gets to the right destination. Each gateway computer on the network checks this address to see where to forward the message. Even though some packets from the same message are routed differently than others, they'll be reassembled at the destination. TCP/IP uses the client/server model of communication in which a computer user (a client) requests and is provided a service (such as sending a Web page) by another computer (a server) in the network. TCP/IP communication is primarily point-to-point, meaning each communication is from one point (or host computer) in the network to another point or host computer. TCP/IP and the higher-level applications that use it are collectively said to be "stateless" because each client request is considered a new request unrelated to any previous one (unlike ordinary phone conversations that require a dedicated connection for the call duration). Being stateless frees network paths so that everyone can use them continuously. (Note that the TCP layer itself is not stateless as far as any one message is concerned. Its connection remains in place until all packets in a message have been received.) Many Internet users are familiar with the even higher layer application protocols that use TCP/IP to get to the Internet. These include the World Wide Web's Hypertext Transfer Protocol (HTTP), the File Transfer Protocol (FTP), Telnet (Telnet) which lets you logon to remote computers, and the Simple Mail Transfer Protocol (SMTP). These and other protocols are often packaged together with TCP/IP as a "suite." Personal computer users usually get to the Internet through the Serial Line Internet Protocol (SLIP) or the Point-to-Point Protocol (PPP). These protocols encapsulate the IP packets so that they can be sent over a dial-up phone connection to an access provider's modem. Protocols related to TCP/IP include the User Datagram Protocol (UDP), which is used instead of TCP for special purposes. Other protocols are used by network host computers for exchanging router information. These include the Internet Control Message Protocol (ICMP), the Interior Gateway Protocol (IGP), the Exterior Gateway Protocol (EGP), and the Border Gateway Protocol (BGP). See SLIP, HTTP, PPP, SMTP and UDP.
TDMA Time Division Multiple Access A technology used in digital cellular telephone communication to divide each cellular channel into three time slots in order to increase the amount of data that can be carried. TDMA is used by Global System for Mobile communications (GSM), See Cellular and GSM
The science of converting sound into electrical signals, transmitting it within cables or via radio and reconverting it back into sound. It refers to the telephone industry in general.
Defined by IETF RFC768, provides a simple, but unreliable message service for transaction-oriented services. Each UDP header carries both a source port identifier and destination port identifier, allowing high-level protocols to target specific applications and services among hosts.
UMTS (Universal Mobile Telecommunications System) UMTS is the European implementation of the 3G (third generation) wireless phone system standard. It is a broadband, packet-based transmission of text, digitised voice, video, and multimedia at data rates up to and possibly higher than 2 Mbps, offering a consistent set of services to mobile computer and phone users no matter where they are located in the world. UMTS provides service in the 2GHz band and offers global roaming and personalised features. These new UMTS networks will build on the success of GSM, and on the GSM operators' existing investment in infrastructure. The first stage of service and network evolution is from today's GSM systems, through the implementation of GPRS, to commercial UMTS networks expected from 2001. The major differentiators of UMTS are: a new air interface operating at around 2GHz which will offer superior performance to GSM in terms of higher data rates and capacity, and a packet-based network architecture which supports both voice and data services. Today's cellular systems are mainly circuit-switched, with connections always dependent on circuit availability. Packet-switched connection, using the Internet Protocol (IP), means that a virtual connection is always available to any other end point in the network. It will also make it possible to provide new services, such as alternative billing methods (pay-per-bit, pay-per-session, flat rate, asymmetric bandwidth, and others). The higher bandwidth of UMTS also promises new services, such as video conferencing. UMTS promises to realise the Virtual Home Environment (VHE) in which a roaming user can have the same services to which the user is accustomed when at home or in the office, through a combination of transparent terrestrial and satellite connections. See GSM
VOIP Voice Over Internet Protocol Voice over IP takes standard voice signals and encodes them using IP. At present most voice signals are carried using circuit switched bearers where a channel is set up and maintained between the calling and called parties for the duration of a call. Using IP results in a very different arrangement where the voice is divided into packets and each packet is sent separately. The benefits of this are that the total bandwidth required can be reduced since nothing need be sent when the caller is not speaking. Long term interest in VoIP is in the convergence of today's networks into a single network for voice and data traffic. See IP
WAP Wireless Application Protocol WAP is a technology designed to provide users of mobile terminals (phones) with rapid and efficient connection to the Internet. WAP is a protocol optimised, not only for use on the narrow band radio channels used by second generation digital wireless systems but also for the limited display capabilities and functionality of the display systems used by today's mobile terminals. WAP integrates telephony services with microbrowsing and enables easy-to-use interactive Internet access from the mobile handset. Typical WAP applications include over-the-air e-commerce transactions, online banking, information provisioning and messaging. WAP will enable operators to develop innovative services to provide differentiation in competitive market environments.
A network that works without wires. The data signals are transmitted over broadcast frequencies. Common examples of wireless equipment in use today include the Global Positioning System (GPS), cellular phones and pagers and cordless computer accessories (the cordless mouse). An increasing number of companies and organisations are using wireless local area networks (LANs). Wireless transceivers are available for connection to portable and notebook computers, allowing Internet access in selected cities without the need to locate a telephone jack. Eventually, it could be possible to link any computer to the Internet via satellite, no matter where in the world the computer might be located.
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