FAQs / GLOSSARY
How is business telecom different from consumer telecom? Business telecom contracts typically include a Service Level Agreement (SLA). SLAs are guarantees that your telecom services “uptime” will be maintained at a certain level. Consumer telecom services typically do not include an SLA.
Like thousands of other people, I run a business from my house. Why can’t I get business telecom services at a residential address? It’s all about the SLAs (see above). Telecom carriers take their SLAs seriously and make sure they have business-grade infrastructure all the way to commercial office locations. Not even the giant carriers can swing the investment necessary to contractually ensure 99%+ uptime to every residential address they serve.
If we switch carriers, can we keep our phone numbers? In most cases, yes.
What things do people typically forget about when specifying telecom needs? Top two “whoops we forgot” items are alarm systems and fax machines. Each of those may have unique connection requirements.
How does Wiresurfer make money? We receive a fee from the telecom carrier.
More FAQs coming soon…
ADSL (Full Rate Asymmetrical DSL) ADSL offers differing upload and download speeds and can be configured to deliver up to six megabits of data per second (6000K), from the network to the customer, that is up to 120 times faster than dial-up service and 100 times faster than ISDN. ADSL enables voice and high-speed data to be sent simultaneously over the existing telephone line. This type of DSL is the most predominant in commercial use for business and residential customers around the world. Good for general Internet access and for applications where downstream speed is most important, such as video-on-demand. ITU-T Recommendation G.992.1 and ANSI Standard T1.413-1998 specify full rate ADSL. ITU Recommendation G.992.3 specifies ADSL2 which provides advanced diagnostics, power saving functions, PSD shaping, and slightly better performance than G.992.1. ITU Recommendation G.992.5 specifies ADSL2Plus, which provides the benefits of ADSL2Plus twice the bandwidth so that bit rates as high as 20 Mb/s downstream can be achieved on relatively short lines.
Asynchronous Transfer Mode (ATM) A cell relay network protocol which encodes data traffic into small fixed-sized (53 byte: 48 bytes of data and 5 bytes of header information) cells instead of variable-sized packets, as found in packet-switched networks such as the Internet Protocol or Ethernet. It is a connection-oriented technology, in which a connection is established between the two endpoints before the actual data exchange begins.
Availability The amount of time that a system is available during time periods when it is expected to be available. Availability is often measured as a percentage of an elapsed year. For example, 99.95% availability equates to 4.38 hours of downtime in a year (0.0005 * 365 * 24=4.38) for a system that is expected to be available all the time. (Provided by SNIA)
Backbone (1) The part of a network used as the primary path for transporting traffic between network segments. (2) A high-speed line, or a series of connections, that forms a major pathway within a network.
Bandwidth (1) Measure of the information capacity of a transmission channel. (2) The difference between the highest and lowest frequencies of a band that can be passed by a transmission medium without undue distortion, such as the AM band – 535 to 1705 kilohertz. (3) Information carrying capacity of a communication channel. Analog bandwidth is the range of signal frequencies that can be transmitted by a communication channel or network. (4) A term used to indicate the amount of transmission or processing capacity possessed by a system or a specific location in a system (usually a network system).
Broadband (1) The ability of a system to carry a multitude of signals simultaneously. In data transmission, it denotes transmission facilities capable of handling frequencies greater than those required for high-grade voice communications. The higher frequency allows the carrying of several simultaneous channels. Broadband infers the use of a service provider signal rather than direct modulation (i.e., baseband).
Cable Modem A modem used by a subscriber for high-speed network access over a coaxial cable, such as those used traditionally to provide cable television service.
Cable Modem Termination System (CMTS) Equipment used to provide high-speed data services, such as cable Internet or Voice-over-IP, to cable subscribers.
Carrier A company that provides communications circuits. Carriers are either “private” or “common.” A “private” carrier can refuse service. A “common” carrier cannot. Most of the carriers in our industry (the local phone company, AT&T, MCI WorldCom, US, Sprint, etc.) are common carriers. cf. Service Provider
Category 5 Cable (CAT 5) An unshielded, twisted-pair cable designed for high signal integrity. The twisting of the cable reduces electrical interference, and the plastic insulation has low dispersion, so the dielectric constant of the plastic does not depend greatly on frequency.
Central Office (CO) (1) The place where common carriers, or service providers, terminate customer lines and locate the switching equipment that interconnects those lines. (2) A centralized location for the Switching, Transmission and Power equipment that provide telephone service.
Channel (1) A communication path. Multiple channels can be multiplexed over a single cable in certain environments. The term is also used to describe the specific path between large computers and attached peripherals. (2) In the case of fiber optic-based transmission systems, an electrical or photonic communications path, between two or more points of termination. (3) The smallest subdivision of a circuit that provides a type of communication service, usually a path with only one direction. (4) A communications path, or the signal sent over that channel. Through multiplexing, several channels can be transmitted over an optical channel.
Collocation Multiple service providers sharing a single facility for housing physical network equipment are said to be collocated. In deregulated telecommunications markets, competing service providers often need to share (indeed, may be required by law to share) a number of physical facilities, such as a central office building and long distance trunks. Typically, established incumbent service providers are required to share their existing facilities with newer competitive service providers. The fact of collocation may limit the amount of space available to a service provider in a given facility, making it desirable for the service provider to fit a large amount of equipment in a comparatively small space.
Compression The process of encoding data to reduce its size. Lossless compression utilizes a technique that preserves the entire content of the original data, and from which the original data can be reconstructed exactly.
Data Rate The number of bits of information transmitted per second, as in a data transmission link. Typically expressed as megabits per second (Mb/s).
Digital Cross Connect System (DCS) A device that provides switching services for various private lines by setting up the necessary connections prior to the corresponding calls. The connections are specified explicitly by an administrator or by the person making the call.
Digital Signal 3 (DS3) A digital signal level 3 T-carrier for which the data rate is 44.736 Mb/s. This level of carrier can transport 28 DS1 level signals and 672 DS0 level channels within its payload.
Digital Subscriber Line (DSL) A method of providing high-speed data services over the twisted pair copper wires traditionally used to provide POTS. Types of DSL include ADSL (asymmetric digital subscriber line), HDSL (high data rate digital subscriber line), SDSL (single line digital subscriber line), and VDSL (very high data rate digital subscriber line).
Disaster Recovery (DR) The recovery of data, access to data and associated processing through a comprehensive process of setting up a redundant site (equipment and work space) with recovery of operational data to continue business operations after a loss of use of all or part of a data center. This involves not only an essential set of data but also an essential set of all the hardware and software to continue processing of that data and business. This may involve down time to perform the recovery.
Dual Link A 3 Gb/s nominal interface used in applications (such as digital cinema) requiring greater fidelity and resolution than standard HDTV can provide.
E1 The European version of the T1 digital transmission link with a line bit rate of 2.048 megabits per second (as used by European Conference of European and Postal Telecommunication [CEPT] Administrations service providers).
Ethernet The predominant local area networking technology, based on packetized transmissions between physical ports over a variety of electrical and optical media. Ethernet can transport any of several upper-layer protocols, the most popular of which is TCP/IP. Ethernet standards are maintained by the IEEE 802.3 committee. The unqualified term Ethernet usually refers to 10 Mb/s transmission on multi-point copper. Fast Ethernet is used to denote 100 Mb/s transmission, also on multipoint copper facilities. Gigabit Ethernet (GbE) and 10 Gigabit Ethernet (10 GbE) utilize optical fiber transmission.
Fiber In The Loop (FITL) Fiber optical technology from central office (CO) to customer premises.
Fiber Optic Cable A transmission medium composed of glass or plastic fibers, rather than copper wire, used to transport data, video and voice signals simultaneously. The signal is imposed on the fiber via pulses (modulation) of light from a LASER or a light-emitting diode (LED). Because of its high bandwidth and lack of susceptibility to interference, fiber optic cable is used in long haul or noisy applications.
Frame Relay An efficient data-transmission technique used to send digital information quickly and cheaply in a relay of frames to one or many destinations from one or many end-points.
Fiber-to-the-x (FTTX) Refers to several different forms of optical fiber architectures, including:
· Fiber-to-the-Building (FTTB) A telecommunications system based on fiber-optic cable carrying network data from an Internet service provider to a customer’s physical building.
· Fiber-to-the-Cabinet (FTTCab) A telecommunications system using passive optical networking as an infrastructure going from an Internet service provider’s central office, or headend, to a remote cabinet, bringing multiplexers closer to the service areas.
· Fiber-to-the-Curb (FTTC) A telecommunications system based on fiber-optic cables run to a platform serving several customers. Each of these customers has a connection to this platform via coaxial cable or twisted pair.
· Fiber-to-the-Exchange (FTTEx) A telecommunications system based on copper wiring run to a customer located close to the Internet service provider’s central office.
· Fiber-to-the-Home (FTTH) or Fiber-to-the-Premises (FTTP) A broadband telecommunications system based on fiber-optic cables and associated optical electronics for delivery of multiple advanced services, such as the Triple Play of telephone broadband Internet and television to homes and businesses.
· Fiber-to-the-Node/Neighborhood (FTTN) A broadband architecture that provides high-speed Internet and other services to the home by running fiber to the node and VDSL over the existing telephone copper plant to the home. Data rates are limited to 25-30 Mb/s.
Gigabit Ethernet (GbE) Describes various technologies for implementing Ethernet networking at a nominal speed of one gigabit per second defined by the IEEE 802.3z and 802.3ab standards. Gigabit Ethernet has recently been overtaken by 10 Gigabit Ethernet (10GbE), which was ratified by the IEEE in 2002, and provides data rates 10 times greater than that of Gigabit Ethernet.
Gigabit Interface Converter (GBIC) A transceiver that converts between electrical signals used by Ethernet, Fibre Channel and FICON devices and either electrical or optical signals suitable for transmission. Gigabit interface converters allow designers to design one type of device and adapt it for either copper or optical applications. GBICs can be hot swapped and software programmed in the field to various protocols.
Gigabits Per Second (Gb/s or Gbps) Billion bits per second. A measure of transmission speed.
Hub A communications infrastructure device to which nodes on a multi-point bus or loop are physically connected. Commonly used in Ethernet and Fibre Channel networks to improve the manageability of physical cables. Hubs maintain the logical loop topology of the network of which they are a part, while creating a “hub and spoke” physical star layout. Unlike switches, hubs do not aggregate bandwidth. Hubs typically support the addition or removal of nodes from the bus while it is operating.
Hybrid Fiber Coaxial (HFC) A network incorporating both optical fiber and coaxial cable to create a broadband network. By using frequency division multiplexing, an HFC network may carry a variety of signal types, including analog TV, digital TV, telephone and data.
Interexchange Carrier (IXC) (1) Any individual, partnership, association, joint-stock company trust, governmental entity or corporation engaged for hire in interstate or foreign communication by wire or radio, between two or more exchanges. (2) A long-distance telephone company offering circuit-switched, leased-line or packet-switched service or some combination thereof.
Internet Protocol (IP) A protocol that provides connectionless best effort delivery of data across heterogeneous physical networks. Data is broken down into a number of small bundles known as packets, and each packet gets transmitted to the destination separately, possibly along a different route than other packets from the same message. Packets are often retransmitted utilizing TCP when data is dropped due to over constrained routing.
Internet Protocol Television (IPTV) A system where a digital television service is delivered to subscribers using Internet Protocol over a broadband connection. This service is often provided in conjunction with Video on Demand and may also include Internet services such as Web access and VoIP, where it may be called Triple Play, and is typically supplied by a broadband operator using the same infrastructure.
Latency Synonym for I/O request execution time, the time between the making of an I/O request and completion of the request’s execution. Latency contributors are light delay through the fiber optic line over distance as well as network element delays caused by excessive protocol conversions or network routing complexities.
Leased Line A physical line that a single subscriber leases from a service provider, giving the subscriber exclusive rights to that line’s capacity.
Line Amplifier Also called an Optical Line Amplifier (OLA). It does not multiplex or demultiplex signals but instead amplifies signals; it does so to maintain signal strength over long distances.
Line Terminating Equipment (LTE) Network elements that originate and/or terminate line signals.
Local Area Network (LAN) A communications infrastructure intended for the local transport of data, video, and voice. Designed to use dedicated wiring over a limited distance (typically a diameter of less than five kilometers) to connect a large number of intercommunicating nodes. Ethernet is the most popular of LAN technologies. LANs are interconnected over distance through Metropolitan Area Networks (MANs) and Wide Area Networks (WANs) that utilize carrier-class transport and switching equipment.
Local Exchange Company (LEC) A telephone company that provides customer access to the worldwide public switched network through one of its central offices.
Megabits per Second (Mb/s or Mbps) A digital transmission speed of millions of bits per second.
Metropolitan Area Network (MAN) A network that connects nodes distributed over a metropolitan (city-wide) area as opposed to a local area (campus) or wide area (national or global).
Moving Picture Experts Group (MPEG) A working group of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC), charged with the development of video and audio encoding standards.
Multicast The simultaneous transmission of content to a subset of more than one of the ports connected to a communication facility.
Multi-protocol Label Switching (MPLS) A method used to direct data traffic in networks in which IP over ATM is being used. In MPLS, IP routers at the edge of the network label packets in a way that greatly facilitates their handling by ATM switches at the network core.
Multiplex The combination of several signals onto a single communications channel.
Multiplexer (MUX) (1) Equipment that enables several data streams to be sent over a single physical line or fiber. (2) A function by which one connection from an ISO layer is used to support more than one connection to the next higher layer.
Multiplexing In data transmission, a function that permits two or more data sources to share a common transmission medium such that each data source has its own channel. Methods of multiplexing include time division multiplexing, and wavelength division multiplexing.
Network An interconnect that enables communication among a collection of attached nodes. A network consists of optical or electrical transmission media, infrastructure in the form of hubs and/or switches, and protocols that make message sequences meaningful. Networks are typically characterized by large numbers of nodes that act as peers, large inter-node separation and flexible configurability.
Network Attached Storage (NAS) Storage elements that connect to a LAN and provide file access services to computer systems. A NAS Storage Element consists of an engine, which implements the file services, and one or more devices, on which data is stored. Much like a SAN, a NAS is used to share storage resources across multiple servers; however, NAS technology does not provide LAN traffic relief.
Network Interface Card (NIC) An I/O adapter that connects a computer or other type of node to a network. The term NIC is universally used in Ethernet contexts. In Fibre Channel contexts, the terms adapter and NIC are used in preference to host bus adapter (HBA).
Open Transport Network (OTN) A network technology that aims at transporting a number of communication protocols over an optical fiber. This includes serial protocols (e.g. RS232) as well as telephony (POTS/ISDN), audio, Ethernet and video (via M-JPEG, MPEG2/4).
Optical Amplifier (OA) A device used to amplify the signal optically without any conversion to an electrical signal. It can be used as a Booster Amplifier, In-Line Amplifier or Pre-Amplifier.
Outside Plant (OSP) The part of the LEC telephone network that is physically located outside of telephone company buildings. Outside Plant includes the local loops from the LEC’s switching centers to the customers’ premises, and all facilities which serve to interconnect the various switches (e.g., central office and tandem) in the service provider’s internal network.
Oversubscription Scheduling a network line to carry a greater volume of data than the line is designed to carry at any one time. Oversubscribing a line assumes that it is unlikely that any one subscriber (or group of subscribers) will use all of the line’s capacity at any one time, and relies on methods such as quality of service to prioritize subscriber traffic during periods of congestion.
Packetize The process by which IP breaks a file/message into numerous small bundles for transmission to a destination. Each packet is independent from the others; it has the destination’s address, and may reach the destination by a different route than other packets for the same file/message.
Performance Monitoring (PM) Measures the quality of service and identifies degrading or marginally-operating systems (before an alarm would be generated).
Point of Presence (POP) A facility used by a network access provider to house physical equipment that enables subscribers to access the network. The term is used to describe the location where a long distance service provider connects to a local service provider, and also the location where an Internet service provider houses equipment that enables dial-up subscribers to access the Internet.
Plain Old Telephone Service (POTS) Analog voice transmission over twisted pair copper wires, without any of the more recently added amenities such as caller ID or call waiting. POTS was invented over a century ago, and is still used widely in public telephone networks.
Protocol A set of rules for using an interconnect or network so that information conveyed on the interconnect can be correctly interpreted by all parties to the communication. Protocols include such aspects of communication as data representation, data item ordering, message formats, message and response sequencing rules, block data transmission conventions, and timing requirements.
Provider A company that provides an interface between the teleservices platform and an installed telephone device, such as a telephone line or fax machine.
Public Network A network operated by common service providers or telecommunications administrations for the provision of circuit-switched, packet-switched and leased-line circuits to the public.
Public Switched Telephone Network (PSTN) The traditional voice network infrastructure, including both local service and long distance service, that has been in use in various parts of the world for up to a century or so.
Quality of Service (QoS) A set of guidelines for prioritizing subscriber data traffic on an ATM network, and for establishing a scale of fees for carrying that traffic, based on specific graduated guarantees of network availability and performance.
Radio Frequency (RF) Refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current fed to an antenna.
Regional Bell Operating Company (RBOC) Local telephone companies created in 1984 as part of the break-up of AT&T. The six RBOCs were Ameritech, Bell Atlantic, Bell South, NYNEX, Southwestern Bell and U.S.West. Ameritch and US West became Qwest; Southwestern Bell became AT&T, and Bell Atlantic and NYNEX became Verizon.
Repeater (1) A device that regenerates and propagates electrical signals between two network segments. (2) A device that restores a degraded digital signal for continued transmission; also called a regenerator. (3) A device which consists of a transmitter and a receiver or transceiver, used to regenerate a signal to increase the system length.
Route A series of network elements that include multiple end-nodes. From a logical and visual viewpoint, a route consists of one or more paths.
Router A device that directs bundles of data being transmitted between nodes on different networks.
Serial Digital Interface (SDI) A digitized video interface used for broadcast-grade video. Standardized in ITU-R BT.656 and SMPTE-259M.
Signal-to-Noise Ratio (SNR) The ratio of signal power to noise power. Measured in dB.
Simple Network Management Protocol (SNMP) An IETF protocol for monitoring and managing systems and devices in a network. The data being monitored and managed is defined by a Management Information Base (MIB). The functions supported by the protocol are the request and retrieval of data, the setting or writing of data, and traps that signal the occurrence of events.
Storage Area Network (SAN) A network whose primary purpose is the transfer of data between computer systems and storage elements and among storage elements. A SAN consists of a communication infrastructure, which provides physical connections, and a management layer, which organizes the connections, storage elements, and computer systems so that data transfer is secure and robust. The term SAN is usually (but not necessarily) identified with the Fibre Channel protocol and block I/O services rather than file access services.
Switch A network infrastructure component to which multiple nodes attach. Unlike hubs, switches typically have internal bandwidth that is a multiple of link bandwidth, and the ability to rapidly switch node connections from one to another. A typical switch can accommodate several simultaneous full link bandwidth transmissions between different pairs of nodes. A switch filters, forwards and directs frames or circuits based on a destination address.
T1 A North American digital standard for transmitting data at 1.544 Mb/s. T1 is often divided into 24 channels (DS0 signals), each transmitting data at 56 kb/s or 64 kb/s.
T3 A North American digital standard for transmitting data at 44.736 Mb/s, the equivalent of 28 T1s.
Throughput The rate at which a computer or network sends or receives data.
Time Division Multiplexing (TDM) A method for transmitting multiple calls over a single line; each call is assigned a recurring timeslot on the line, and a small portion of that call gets transmitted over the line each time its assigned timeslot is available.
Transmission Control Protocol/Internet Protocol (TCP/IP) (1) A family of IP-based protocols which facilitate the transmission of data packets over various media in various circumstances. TCP/ IP provides the basis of the Internet and also of many subscriber services. (2) A set of protocols developed to link dissimilar computers across many kinds of networks.
Virtual Private Network (VPN) A network service which employs encryption and tunneling to provide a subscriber with a secure private network that runs over public network infrastructure.
Virtualization The act of integrating one or more (back end) services or functions with additional (front end) functionality for the purpose of providing useful abstractions. Virtualization typically hides some of the back end complexity, or adds or integrates new functionality with existing back end services. Examples of virtualization are the aggregation of multiple instances of a service into one virtualized service, or to add security to an otherwise insecure service. Virtualization can be nested or applied to multiple layers of a system.
Voice-over-Internet Protocol (also called VoIP, IP Telephony, Internet telephony, or Digital Phone) The routing of voice conversations over the Internet or any other IP-based network. The voice data flows over a general-purpose packet-switched network, instead of traditional dedicated, circuit-switched voice transmission lines.
Wi-Fi (also WiFi, Wi-fi, Wifi, or wifi) Products which pass testing to demonstrate that they implement a set of product compatibility standards for Wireless Local Area Networks (WLANs) based on IEEE 802.11 specifications. Wi-Fi allows a wireless-enabled computer or Personal Digital Assistant (PDA) to connect to the Internet when in proximity to an access point.
xDSL A generic term for Digital Subscriber Line; the “x” is a placeholder for any of several other letters that indicate the particular type of DSL in use including ADSL, HDSL, IDSL, SDSL, and VDSL