 56K The term 56K refers to a new generation of modems that improve the speed of communication between personal computers and the Internet. The previous speed standard of v.34 provided communication at speeds as high as 33,600 bits per second (bps). The new 56K modems increase that speed to a theoretical maximum of 57,600 or 56 Kbps. In the past, two different technologies emerged enabling 56K communication: K56flex and x2. They have been replaced by a new, international standard for 56K data communications known as v.90.
ADSL Asymmetric Digital Subscriber Line (ADSL) is the most popular form of DSL technology.
ADSL Lite A lower data rate version of Asymmetric Digital Subscriber Line (ADSL).
Bandwidth The amount of data that can be transmitted over a given time.
Bit A contraction of the "binary digit". A bit is the smallest possible unit of storage of computer information and can one of two values. These values are typically represented by 0 and 1, low and high, or on and off.
Broadband A term for high-speed, high-capacity Internet and data connections.
CAP Carrier-lessAmplitude/Phase (CAP) modulation; incoming data modulates a single carrier that is then transmitted down a telephone line. The carrier itself is suppressed before transmission (it contains no information,and can be reconstructed at the receiver), hence the adjective"carrier-less." CAP and DMT are two modulation systems currently on the market for ADSL.
Dedicated Access A direct connection between a terminal and a service, network or computer dedicated to the specific use of a particular customer.
Dial access Ability to access the Internet through a dial up connection.
DMT DiscreteMulti-Tone (DMT) multi-carrier modulation uses 256 QAM modulation tones simultaneously to create the ADSL signal. DMT is the basis of ANSI Standard T1.413, and has the support of other world standards bodies. CAP and DMT are two modulation systems currently on the market for ADSL.
DSL Digital Subscriber Line (DSL) provides a dedicated digital circuit between a residence and a telephone company's central office, allowing high-speed data transport over existing twisted copper telephone lines.
EtherLoop EtherLoop is currently a proprietary technology from Nortel, short for Ethernet Local Loop.
E-mail address Electronic identification that enables users to send and receive electronic mail.
Ethernet card The ethernet card provides a standardized way of connecting computers together to create a network. Because DSL technology requirements far exceeds the lower speed limits of standard serial/parallel connections now built-in most PCs, a connection technology capable of interfacing at higher speeds was required. Ethernet technology, capable of sustaining traffic volumes of up to 10MB, was chosen as the technology of choice.
Filter A device that prevents noise interference and is installed between a telephone and its wall jack.
Firewall A system designed to prevent unauthorized access to or from a private network. Firewalls can be implemented in both hardware and software, or a combination of both. Firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet, especially Intranets. All messages entering or leaving the Intranet pass through the firewall, which examines each message and blocks those that do not meet the specified security criteria. A firewall is considered a first line of defense in protecting private information. For greater security, data can be encrypted.
There are several types of firewall techniques:
*Packet filter: Looks at each packet entering or leaving the network and accepts or rejects it based on user-defined rules. Packet filtering is fairly effective and transparent to users, but it is difficult to configure. In addition, it is susceptible to IP spoofing.
*Application gateway: Applies security mechanisms to specific applications, such as FTP and Telnet servers. This is very effective, but can impose performance degradation.
Circuit-level gateway: Applies security mechanisms when aTCP(tm); or UDP connection is established.Once the connection has been made, packets can flow between the hosts without further checking.
*Proxy server: Intercepts all messages entering and leaving the network. The proxy server effectively hides the true network addresses.
Gateway This is a device that converts different proFAQs Homeols; a network interconnectivity device that translates communications proFAQs Homeols.
In networking, it is a combination of hardware and software that links two different types of networks. Gateways between e-mail systems, for example, allow users on different e-mail systems to exchange messages.
Gateway Address A gateway address is the IP address of a network point that acts as an entrance to another network. For example, in a corporate network, a proxy server acts as a gateway between the internal network and the Internet.
Hub A common connection point for all devices connected to a star network. A passive hub simply serves as a conduit for the data, enabling it to go from one device to another. So called intelligent hubs include additional features that enable them to act as a bridge, transferring data between different types of networks. Some hubs are full-fledged computers that also act as network servers.
HDSL High Bit-rate Digital Subscriber Line (HDSL) is generally used as a substitute for T1/E1.
Internet A wide-area network that connects tens of millions of computers worldwide. Originally implemented by the U.S. Defense Department, Internet is now administered by an independent organization.
IDSL ISDN based DSL developed originally by Ascend Communications.
Kbps Kilobits-per-second (thousands of bits-per-second). A measure of data transmission, such as that handled by a modem.
Line A communications channel. Also called a circuit, trunk or facility. It often refers to customer access to the public switched telephone network (e.g., residence line, individual business line).
LAN Local Area Networks.
Mbps Megabits-per-second (millions of bits-per-second). A measure of data transmission, such as that handled by a modem.
Modem Device that modulates and demodulates data usually transmitted over a regular telephone line.
MSO Multiple service operator synonymous with cable provider.
NAP Network Access Point (NAP) is a high-speed interconnection service that gives Internet Service Providers access to the new Internet infrastructure.
NIC Network Interface Card; an Ethernet adapter "PC card" that needs to be installed in the computer when certain DSL modems are used. Along with the modem, the NIC enables the DSL connection at the customer's home or business.
Network A series of points interconnected by telecommunications channels.
Port The entrance or access point to a computer or multiplexer.
Proxy Server A server that sits between a client application, such as a Web browser,and a real server. It intercepts all requests to the real server to see if it can fulfill the requests itself. If not, it forwards the request to the real server. Proxy servers can also be used to filter requests. For example, a company might use a proxy server to prevent its employees from accessing a specific set of Web sites.
PVC Private Virtual Circuit (PVC) is a point-to-point circuit from the customer premise equipment to either their Internet Service Provider(ISP) or Enterprise Network.
Router A device that connects two LANs. Routers are similar to bridges, but provide additional functionality, such as the ability to filter messages and forward them to different places based onvarious criteria. The Internet uses routers extensively to forward packets from one host to another.
RADSL Rate Adaptive Digital Subscriber Line (RADSL) is any rate adaptive DSL modem,but may specifically refer to a proprietary modulation standard designed by Globespan Semiconductor.
Streaming A method of delivering information (usually sound and/or video) over the Internet such that it can be played on a receiving computer at the same time it is being delivered.
Subnet A portion of a network that shares a common address component. On TCP/IPnetworks, subnets are defined as all devices whose IP addresses have the same prefix. For example, all devices with IP addresses that start with 100.100.100 would be part of the same subnet. Dividing a network into subnets is useful for both security and performance reasons. IP networks are divided using a subnet mask.
Symmetric Digital Subscriber Line (SDSL) is a 2-wire implementation of (HDSL).
Telnet A terminal emulation program for TCP/IP networks such as the Internet. TheTelnet program runs on your computer and connects your PC to a server on the network. You can then enter commands through the Telnet program and they will be executed as if you were entering them directly on the server console. This enables you to control the server and communicate with other servers on the network. To start a Telnet session, you must log into a server by entering a valid user name and password. Telnet is the most common way to remotely control Web servers.
v.90 A new, international standard for 56K data communications.
VDSL Very High Bit-rate Digital Subscriber Line (VDSL) is proposed for shorter local loops, perhaps up to 3000 ft.
WAN Wide area networks.
XDSL Refers to the family of digital subscriber line technologies, such as ADSL, HDSL, and RADSL.
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