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Broadband Glossary

0845 058 9000
  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z

  1. A

    ADSL (Broadband)
    ADSL stands for Asymmetric Digital Subscriber Line and is the technology used to deliver Broadband over your existing phone system. It is an always on connection, which does not tie up your phone line. It is asymmetric as it has different download and upload speeds.
    ADSL Move
    Moving premises? Take your Zen Broadband with you, there is no activation fee and you keep the same user details, password and IP address(es) with our ADSL Move service.
    Simultaneous move occurs when the phone line is activated. Please note that a number of criteria need to be met for a simultaneous move to take place. Please contact our Customer Services Team on 0845 058 9000 for further details.
    Analogue Signal
    An electronic transmission that can vary in frequency and volume, commonly used by broadcast and phone signals. It can transmit analogue or digital data as a modem can be used to convert analogue to digital information to and from your computer.
    Anti-Virus
    Zen provides free anti-virus protection for your mailbox. We will automatically scan e-mails at our border mail servers to reject any viral payloads before they can enter our network.
    Apple Support Team
    Zen has a dedicated Mac support team, available at local call rate. This team receives ongoing training and so remains up to date with the systems to help you.
    Asynchronous Transfer Mode (ATM)
    Asynchronous Transfer Mode (ATM) is a network technology based on transferring data in cells or packets of a fixed size.

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  2. B

    Bandwidth
    The capacity of your Internet connection for transmitting or receiving data. Measured in Kilobits per second (Kbps) or Megabits per second (Mbps).
    bits per second (bps)
    A measure of how fast data is transferred from one place to another.
    Broadband Remote Access Server Profile
    The Broadband Remote Access Server Profile (or BRAS Profile) is responsible for regulating the maximum data rate you will receive on IPStream Max/Max Premium services.
    This is initially set to 2Mbps (if the line rate achieves is above 2172Kbps), but will rise if your line can support higher speeds than this. If your line performs significantly better than 2Mbps then initial changes should take place within 48 hours.
    If your line is only marginally better than 2Mbps then any increase in speed could take up to five full days.
    Broadband
    A permanent connection to the Internet that also enables your telephone line to remain available. ADSL and SDSL are examples of broadband technology.
    Broadband Router
    A device which connects one or more computers to the Internet. Broadband Routers can be wired, wireless or both.

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  3. C

    Contention Ratio
    With ADSL lines the network bandwidth available is contended (shared) between a pre-determined number of subscribers.

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  4. D

    DACS (Digital Access & Carrier System)
    When BT install phonelines they sometimes provision 2 lines down the same copper line in order to save space. This provides problems as Broadband requires a single dedicated line in order to work.
    When your order is placed the DACS will be highlighted and cause the order to be held in a delayed state. The solution to this is for a BT Engineer to visit your location and split this line by removing the DACS. When this has completed the order will resume.
    The location of the DACS determines the length of the delay and whether it can be removed. DACS can occur anywhere on the phoneline, therefore once it has been located it will be removed. In some cases DACS will occur inside the customers premises, therefore an appointment will be made by Zen for a BT Engineer to visit the premises.
    Data Rate
    Data rate, or throughput, refers to the speed at which you are able to download and upload information from Web sites or other services on the Internet.
    Dial-Up
    Also called narrowband, this is the original connection to the internet using a phone line and a modem. It provides a standard connection of 56Kbps.
    Back up dial in number is 0845 6000 194. You will use the same log-in username and password as you do with you Broadband account.
    DNS (Domain Name System)
    The system whereby Internet domain names are located and translated into Internet Protocol (IP) addresses.
    Download
    The process of transferring data from a network or the Internet onto your computer.
    (Opposite: Upload)
    Downstream
    A transmission from a server towards an end user.
    (Opposite: Upstream)
    With ADSL technologies, the rates of data transfer upstream and downstream are not the same. Downstream data rates are higher since the kind of information that needs to get to the user (including still and video images and sound) requires a higher data rate. User responses back to the computer on the upstream path can be smaller since they are usually text-only. (Upstream data rates are also lower due to the technical restrictions of the technology).
    DSL (Digital Subscriber Line)
    A technology enabling very high speed information transfer over ordinary telephone lines.
    Telephone wires are capable of handling more than just phone conversations, and DSL exploits this "extra capacity" to carry information on the wire without disturbing the line's ability to carry conversations.
    DSLAM (Digital Subscriber Line Access Multiplexer)
    A mechanism at a phone company's central location that links many customer DSL connections to a single high-speed line.
    DLM (Dynamic Line Management)
    Dynamic Line Management (or DLM) is a collective term for the systems used by BT to stabilise an IPStream Max/Max Premium services. It automatically logs information on a line's performance and takes steps to stabilise the line. It can do this by applying Interleaving, and/or reducing the maximum speed a line can connect at. DLM should result in a stable service being established over the first three days after receiving your broadband service. During this training period disconnections may be experienced when changes in line speeds occur.

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  5. E

    Exchange
    Telephone lines go through a local exchange in order to reach the rest of the telephone network. The exchange separates voice from data communications and forwards them on to the correct part of the telephone network.

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  6. F

    Fast Mode
    This is the default mode of the Zen Pro and Zen Active services if interleaving is not required to stabilise the line.
    FTR (Fault Threshold Rate)
    The fault threshold rate (or FTR) is 80% of the MSR. If the line rate drops below the FTR for more than 8 hours in a week period it is considered a fault and a low threshold breach fault can be raised.
    Filter (also see Microfilter)
    Blocks the ADSL signal on a telephone line so that no audible interference reaches the telephone device (E.g., handset, fax machine, satellite receiver).
    Firewall
    A piece of security hardware or software that prevents unauthorised users from accessing private networks connected to the Internet, for example Intranets.
    Firewalls separate computers from the Internet and check packets of data as they arrive in to the Firewall or out of the computer to decide if they should be allowed to enter or be blocked if they do not meet the stated security criteria.

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  7. G

    (Default) Gateway
    A connection point to an external network, typically the Internet.
    GB (Gigabyte)
    Equivalent to about 1 billion Bytes.
    G.DMT
    This is the Discrete MultiTone standard that modems have to adhere to for ADSL capability.

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  8. H

    Hardware
    The equipment needed for a broadband connection e.g. Broadband Router.

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  9. I

    Interleaving
    Interleaving provides error correction on lines. It is used to stabilise a line at higher speeds by providing additional information which is used to fix problems caused by errors occurring on the line.
    Interleaving can result in higher latency (pings), which could affect game play if latency on a line is high prior to switching to the 8000 services.
    Interleaving is automatically applied if BT's Dynamic Line Management systems determine it is necessary to maintain a higher speed connection. An option is available to disable it if it affects the customer's ability to play games and use other latency-sensitive applications.
    IP (Internet Protocol)
    A unique number identifying the location of your computer on the Internet, enabling it to communicate with other computers, e.g. 123.456.7.891.
    Computers use IP addresses to locate and talk to each other on the Internet, much the same way people use phone numbers to locate and talk to one another on the telephone. When you want to access a Web site, your computer asks a domain name system (DNS) server for the IP address and your computer uses the answer it receives to connect you to your required Web site.
    IPStream Max (Zen Pro, Zen Active and Zen Lite on exchanges enabled for up to 8Mbps services only)
    Line Rate Performance Threshold
    288Kbit/s 50-250Kbit/s
    from 288Kbit/s to 576Kbit/s 50-500Kbit/s
    from 576Kbit/s to 1152Kbit/s 200-1000Kbit/s
    from 1152Kbit/s to 2272Kbit/s 400-2000Kbit/s
    from 2272Kbit/s to 8128Kbit/s 600-7150Kbit/s
    IPStream Max Premium (Zen Office and Zen Office Max on exchanges enabled for up to 8Mbps services only)
    Line Rate Performance Threshold
    288Kbit/s 100-250Kbit/s
    from 288Kbit/s to 576Kbit/s 100-500Kbit/s
    from 576Kbit/s to 1152Kbit/s 400-1000Kbit/s
    from 1152Kbit/s to 2272Kbit/s 800-2000Kbit/s
    from 2272Kbit/s to 8128Kbit/s 1200-7150Kbit/s
    ISDN (Integrated Services Digital Network)
    A service provided by most telephone carriers that enables the transmission of voice and data.
    IPStream Max
    This is the BT service on which a Zen Pro, Zen Active and Zen Lite are based on exchanges enabled for up to 8Mbps services only. It allows for downstream line rates of up to 8192Kbps, and upstream line rates of up to 448Kbps.
    IPStream Max Premium
    This is the BT service on which Zen Office and Zen Office Max are based on exchanges enabled for up to 8Mbps services only. It allows for downstream line rates of up to 8192kbps, and upstream line rates of up to 832kbps.

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  10. L

    LAN (Local Area Network)
    A high speed network that connects computers, printers and other network devices together in, for example, an office building.
    Line Rate
    Line rate, or synchronisation(sync) speed is the speed at which your broadband router or modem communicates with the BT Exchange. This is always higher than the speed data will actually be downloaded or uploaded when you use the connection.

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  11. M

    MAC Code (Migrations Authority Code)
    Used to authenticate the migration request from one ISP to another.
    The use of a MAC makes migrations between ISPs simpler and quicker to validate enabling the migration to be completed in a much shorter timescale than previously possible
    MSR (Maximum Stable Rate)
    The maximum stable rate (or MSR) is a line rate threshold established by BT over the first 10 days of service on your broadband service. It is used to determine when a drop in line rate would be considered a fault. Once an MSR is established BT will accept a fault report if the line rate drops by 20% or more. e.g. if the MSR established is 8192kbps a fault can be reported when the line rate drops to 5734Kbps or less.
    Mailbox
    Location where your e-mails are stored and received.
    Can provide privacy as each mailbox is associated with its own username and password
    Mail Server
    Essential for the correct operation of e-mail systems, this is a program which receives e-mail messages and sends them to the right addresses.
    Master Socket
    The main BT socket outlet on a telephone line – the one that enters your house.
    MB (Megabyte)
    Equivalent to about 1 million Bytes.
    Microfilter
    A small device that plugs into your normal BT telephone socket and splits the line into both a standard BT telephone socket and an ADSL broadband socket.
    Migration
    Move seamlessly between Internet Service Providers (ISPs) using a MAC Code. This ensures minimal downtime as there is no cancellation period; you simply swap providers.

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  12. N

    NAT (Network Address Translation)
    A method of connecting to the Internet using just one IP address.
    The NAT system is set up as a way of only using one public-facing IP address, giving any machines or devices connected to the Internet behind this a private address. This is accessible only to other devices on the same network, making a NAT setup secure from external malicious "attacks".
    Network
    A system which enables computers to connect together to share information and access hardware and printers.
    Noise Level
    Also known as Noise Margin.
    This refers to the level of background noise on a telephone line and differs depending upon the characteristics of that line e.g. short/long line, good/low quality copper. The lower the noise level, the better the quality of line, and theoretically enabling faster services to be delivered on it.

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  13. O

    Operating System (OS)
    Computer software that controls hardware and provides services to other programs. E.g. MacOS, UNIX, Linux and Windows.
    NB: (UNIX and Linux, are the most popular operating systems for servers on the Internet)

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  14. P

    PAT (Port Address Translation)
    A type of network address translation (NAT). During PAT, each computer on a LAN is translated to the same IP address, but with a different port number assignment.
    POP3
    A standard protocol for receiving e-mail.
    Port Forwarding
    A feature built into broadband routers which perform NAT. It allows you to create maps between the Internet and your computer network.
    For example, you may run a Web Server on port 80 of machine 10.0.0.5, and may want this server accessible from the Internet. A rule can be added to the router so that any requests that are not replies to those from the local network on port 80 are forwarded to IP address 10.0.0.5. You can assign a global rule so that all ports are forwarded to one internal server, or you can specify different IP addresses for different ports. So if you have a different IP address for your FTP server, you can specify this rule in the routers configuration also.
    Port
    2 key meanings:
    1. A place where information goes into or out of a computer, or both e.g. serial or USB port.
    2. A number that is part of a URL, appearing after a colon (:) right after the domain name. Every service on an Internet server listens on a particular port number on that server, e.g. Web servers normally listen on port 80.
    PPP (Point to Point Protocol)
    The most common protocol used to connect home computers to the Internet over regular phone lines.
    PPPoA (Point to Point Protocol over Asynchronous Transfer Mode)
    This is the standard for ADSL (Broadband) used in the UK. The Zen network fully supports this method.
    PPPoE (Point to Point Protocol over Ethernet)
    An alternative standard used for ADSL (Broadband). This is not fully implemented in the UK, therefore we recommend the use of PPPoA.
    Protocol
    An agreed-upon format for transmitting data between two devices.
    Importantly, your computer or device must support the right protocols if you want to communicate with other computers.
    PSTN (Public Switched Telephone Network)
    The international telephone system based upon copper wires carrying analogue voice data.

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  15. R

    Rate Adaptive
    IPStream Max/Max Premium are referred to as a 'Rate Adaptive' services - this means the service will change the line rate based upon line conditions, which can vary over time. Due to fluctuations in line quality a line could Rate Adapt from a higher speed during the day to a lower speed at night.
    Regrade
    If you want to change an aspect of your package, be it the speed of your line or the number of IP addresses you have, you will need to purchase a regrade for that particular item.
    RIPE (Réseaux IP Européens)
    An Internet registry that supplies and administers IP addresses
    Routed IP
    A publicly accessible IP address (also know as No NAT)
    Our Broadband services are offered with either 1 IP (NAT) or multiple IPs (routed)
    Router
    A device which connects one or more computers to the Internet. Broadband routers can be wired, wireless or both

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  16. S

    SDSL (Symmetrical Digital Subscriber Line)
    A version of DSL where the upload and download speeds are the same.
    Server
    See:
    Simultaneous Provide
    Zen participates in the Simultaneous Provision scheme, which means that we can organise for a BT line to be installed with a Zen Broadband connection at your new premises with minimum hassle. For more information on this please contact Customer Services on 0845 058 9000.
    SMTP (Simple Mail Transfer Protocol)
    The main protocol used to send electronic mail from server to server on the Internet.
    SMTP is a protocol for transferring e-mail across the Internet. You send e-mail with SMTP and a mail handler receives it on your recipient's behalf. Then the mail is read using POP3 or IMAP.
    Spliter
    See Microfilter.
    Switchboard
    Also known as PBX (Private Branch Exchange)
    A private telephone network used by companies where users share a certain number of outside lines for making external telephone calls.

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  17. T

    TCP / IP (Transmission Control Protocol / Internet Protocol)
    The basic communication language or protocol of the Internet.
    TCP / IP is a two-layer program. Transmission Control Protocol assembles the message / file into smaller packets that are transmitted over the Internet and then reassembled into the original message. Internet Protocol ensures each packet gets to the right destination.
    Timescales
    New Broadband Connection 5-7 working days
    Migration to Zen Broadband 2-7 working days
    SDSL 10 working days
    Regrades 2-7 working days
    ADSL Move If you are given a new line number at your new location, the order is likely to be processed within the standard 5-7 working day lead time. If you are taking the same line number with you to your new location, we will need to cease the old service before BT Wholesale will allow a new order to be placed on that number. In these circumstances, the lead time is usually around 2 weeks.

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  18. U

    Upload
    To copy a file from a local computer connected to the Internet to a remote computer.
    (Opposite: Download)
    Upstream
    A transmission from a user towards the server.
    (Opposite: Downstream)
    With ADSL technologies, the rates of data transfer upstream and downstream are not the same. Downstream data rates are higher since the kind of information that needs to get to the user (including still and video images and sound) requires a higher data rate. User responses back to the computer on the upstream path can be smaller since they are usually text-only.

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  19. V

    VoIP (Voice-over Internet Protocol)
    Hardware and software that enables people to use the Internet to make telephone calls by sending voice data in packets using IP rather than by traditional methods.
    VPI / VCI (Virtual Path Identifier / Virtual Channel Identifier)
    VPI and VCI settings define how the modem sets up the connection. VPI is an eight-bit field and VCI is a 16bit field in an ATM cell’s header that identifies the cell’s next destination as it travels through an ATM network.
    An (Asynchronous Transfer Mode) switch uses either the VPI, the VCI, or a combination of both to route the cell to its destination.
    VPN (Virtual Private Network)
    Organisations use VPN to connect remote offices together (LAN to LAN) and provide access for remote workers who are away from the office (Teleworker to LAN).

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  20. W

    WAN (Wide Area Network)
    A geographically dispersed telecommunications network. The term distinguishes a broader telecommunication structure from a local area network (LAN), e.g. between buildings, cities and even countries.
    Webmail
    Zen provides this secure service that allows you to send and receive e-mail from anywhere with a Web browser and Internet connection, good for when you’re travelling or working outside the office.
    Web Server
    A computer that delivers Web pages. Your browser will form a connection to a Web server so that you can request pages from the internet and receive them on your computer.
    Wireless Broadband
    Having a Wireless broadband connection with equipment that allows multiple computers on the network without the inconvenience of wires, great for laptop users.
    1. 1. Using a wireless broadband connection you can bring your laptop back from work and send a spreadsheet to your home PC in the study.
    2. 2. With a wireless broadband connection you could just as easily order the weekly groceries online in the kitchen.
    3. 3. Play on a games console in the bedroom - tucked away from the home PC in the study.
    4. 4. Watch streaming video content on a PC of the latest news from the BBC in the living room.
    5. 5. You can also relax and listen to online radio on your laptop whilst sunbathing in the garden with a wireless broadband connection.

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