The terms below may or may not be used in these documents, but are commonly used in the delivery of DSL.
Activation Date
This is the date when the telephone Company/ISP turn on ADSL on your line. This is assuming that you are within the distance constraints of ADSL.
ADSL
Asymmetric Digital Subscriber Line. A high-speed transmission technology using existing telephone lines that allow simultaneous phone conversations and Internet access. The downstream rates are greater than the upstream rate.
ARP (Address Resolution Protocol )
ARP is a TCP/IP protocol for mapping an IP address to a physical machine address that is recognized in the local network, such as an Ethernet address.
A host wishing to obtain a physical address broadcasts an ARP request onto the TCP/IP network. The host on the network that has the IP address in the request then replies with its physical hardware address.
Inverse ARP (In-ARP), on the other hand, is used by a host to discover its IP address. In this case, the host broadcasts its physical address and a RARP server replies with the host’s IP address.
ATM
Asynchronous Transfer Mode. A connection-oriented switching technology that uses fixed-length cells. It is common for phone companies to use ATM to transfer data around the Internet.
Bps
Bits per second. Indicates the speed at which data bits are transferred.
Bridged Ethernet
Also referred to as RFC1483, not currently activated in the UK
CPE
Customer Premises Equipment. Your DSL modem is considered CPE equipment. It resides at your premises and connects you to the Telephone company network and then your ADSL Service Provider.
DHCP
Dynamic Host Configuration Protocol. A TCP/IP protocol that provides for automatic/dynamic IP addresses. If your computer is set for DHCP, your ISP will automatically assign you an IP address each time you log on to the network.
DMT
Discrete Multi-Tone. DSL technology that uses DSPs to code information for use in a DSL network. Currently in use in the UK.
DNS
Domain Name Server. Servers on the Internet or at the ISP that maintain associations between IP addresses and Domain Names. DNS allows the user to type in a name (www.robabdul.com) instead of the numeric IP address.
Downstream
Refers to the transmission direction from the Exchange to the Modem. Usually measured in Kbps.
DSL
Digital Subscriber Line. The high speed local-loop connection between the Exchange and your Modem. It provides concurrent telephony and Internet browsing over the same pair of wires. You will only need one phone number.
DSLAM
Digital Subscriber Line Access Multiplexer. This is the equipment installed at the phone companys Exchange that allows for ADSL. It splits your regular voice traffic from data traffic. Your Exchange must have the proper DSLAM for you to get DSL.
DSP
Digital Signal Processor. A chip on the modem that handles line signalling.
DUN
Dial-up Networking. This is a Microsoft application that is used to connect to the Internet when using a PPPoA connection type. It was first used to connect analogue modems.
Dynamic IP Address
This is a service provided by your ISP that automatically assigns you a random IP address from one of their pool of addresses. Your address may change each time you log on to the network. If you are hosting a Web server, you do not want to have a dynamic IP address. You should use a static address.
FAQ
Frequently Asked Questions.
G.Lite
G.Lite is the informal name of a way to deploy DSL services to home and small-business users. Also known as Universal ADSL, G.Lite makes it possible to have Internet connections to home and business computers at up to 4.0 Mbps (millions of bits per second) over regular phone lines. A technology that is not used extensively and not in the UK.
IP
Internet Protocol. The networking protocol used as the primary method for transferring data over the Internet. It is also used in many LANs.
ISP
Internet Service Provider – A company that provides you with access to the Internet. In these guides they are referred to generically as Service Providers. This can be either a Telephone company or one of many separate companies. To get Internet access you must have a Service Provider account that supports DSL and an activated ADSL line. Your ISP will provide you with the necessary account information.
Kbps
Kilobits per second. One K is 1,024 bits.
Last Mile
This is also referred to as the Local Loop. It is the distance between the CPE equipment and the Exchange.
LAN
Local area network. Used to link a number of computers together in a home or business. The Ethernet side of the ADSL Router is called the LAN port. It is a twisted-pair Ethernet 10Base-T interface. A hub can be connected to the LAN port. More than one computers, such as server or printer, can be connected through this hub to the ADSL Router and composes a LAN.
Local Loop
The distance between the Exchange equipment and the customers premises. Also known as the Last Mile.
Mail Server
Mail servers are located at the ISP and hold and route your e-mail until you access it. There are incoming and outgoing mail servers. Find out from your ISP what the name of your mail servers are.
Mbps
Megabits per second. One megabit is 1,048,576 bits.
Microfilter
Microfilters are devices that connect between your telephone and the phone socket. Because DSL allows voice and data to share the same pair of wires, Microfilters (like POTS splitters) keep the signals from interfering with each other. If you hear excess noise on your telephones after DSL service has been activated, make sure that your Microfilters are installed or that you have good quality filters.
Name Server
Name servers translate names from one form into another. For example, the Internet relies on Domain Name Servers (DNSs) that translate domain names (for example, www.robabdul.com) into IP addresses (for example, 225.225.225.0).
NAT (Network Address Translation)
NAT is an Internet standard that translates a private IP within one network to a public IP address, either a static or dynamic one. NAT provides a type of firewall by hiding internal IP addresses. It also enables a company to use more internal IP addresses.
If the IP addresses given by your ISP are not enough for each PC on the LAN and the ADSL Router, you need to use NAT. With NAT, you make up a private IP network for the LAN and assign an IP address from that network to each PC. One of some public addresses is configured and mapped to a private workstation address when accesses are made through the gateway to a public network.
For example, the ADSL Router is assigned with the public IP address of 168.111.2.1. With NAT enabled, it creates a Virtual LAN. Each PC on the Virtual LAN is assigned with a private IP address with default value of 192.168.1.2 to 192.168.2.254. These PCs are not accessible by the outside word but they can communicate with the outside world through the public IP 168.111.2.1.
News Server
News servers are located at the ISP. They hold and route messages from Internet news-groups. You can subscribe to newsgroups for reading and replying to messages. Contact your ISP for more information about using their news server.
NIC
Network Interface Card. A board that often resides in the computer that connects a computer to a network (LAN).
NTE
Network Terminating Equipment. This is the box that attaches to the customers house at the where your telephone line enters the house.
PVC
Permanent Virtual Circuit. A PVC is the combination of the VPI/VCI pair. This pair of numbers is used to identify a route through an ATM/ADSL network. The current default setting is 0,38.
POTS
Plain Old Telephone Service. Refers to the standard telephone service used in most homes.
POTS Splitter
A device that separates the POTS information from the DSL information. Because DSL and POTS share the same line, it is necessary to keep the two signals from interfering with each other. A POTS splitter will be situated at Network Terminating Equipment (where the line enters the premises), other times, a Microfilter will be used.
PPPoA
Point-to-Point over ATM Protocol (also sometimes seen as simply PPP). A protocol that some ISPs use to give users access to the ISPs computers and the Internet. You will currently need PPPoA, but the BT Voyager USB can support many protocols (Bridged Ethernet, Routed Ethernet, or Point-to-Point Protocol over Ethernet (PPPoE).
PPPoE
Point-to-Point over Ethernet (also sometimes seen as simply PPP). A protocol that some ISPs use to give users access to the ISPs computers and the Internet. You will currently need PPPoA, but the BT Voyager USB can support many protocols (Bridged Ethernet, Routed Ethernet, or Point-to-Point Protocol over ATM (PPPoA).
Private IP Address
Private IP addresses are also LAN IP addresses, but are considered “illegal” IP addresses to the Internet. They are private to an enterprise while still permitting full network layer connectivity between all hosts inside an enterprise as well as all public hosts of different enterprises.
The ADSL Router uses private IP addresses by assigning them to the LAN that cannot be directly accessed by the Internet or remote server. To access the Internet, private network should have an agent to translate the private IP address to public IP address.
Public IP Address
Public IP addresses are LAN IP addresses that can be considered “legal” for the Internet, because they can be recognized and accessed by any device on the other side of the DSL connection. In most cases they are allocated by your ISP.
If you are given a range of fixed IP addresses, then one can be assigned to the router and the others to network devices on the LAN, such as computer workstations, ftp servers, and web servers.
RFC1483
A standard that provides guidelines for Bridged Ethernet and Routed Ethernet connection protocols. (PPPoA, PPPoE etc). Current protocol used in the UK is PPPoA.
Routed Ethernet
Also referred to as RFC1483, this is a protocol that some ISPs use to give access to their computers and then to the Internet. Current setting in the UK is PPPoA.
Router
A device that directs LAN traffic through a network.
Static IP Address
This is an IP address that has been permanently assigned to you by your ISP.
TCP/IP
Transmission Control Protocol/Internet Protocol. The most widely used protocol suite of the World Wide Web.
Training up
With DSL, a negotiation needs to be made between the Modem equipment and the Exchange equipment (DSLAM). This process is called Training. When they have successfully talk to each other, they are considered Trained. Your modem must be Trained before you can pass any traffic or browse the Internet. Training will establish your speed and line quality. When this has been successfully completed both your lights will solid green.
Upstream
Refers to the transmission speed from your modem to the Exchange equipment. (Downstream is from the Exchange to your Modem).
VCI
Virtual Circuit Identifier. This number is part of the PVC. It establishes your channel through the telephone company equipment. Default setting is 0.
Virtual Server
You can designate virtual servers, e.g., a FTP, web, telnet or mail server, on your local network and make them accessible to the outside world. A virtual server means that it is not a dedicated server — that is, the entire computer is not dedicated to running on the public network but in the private network.
VPI
Virtual Path Identifier. This is part of the PVC. This, combined with the VCI, establishes your channel through the phone company equipment. Default setting is 38.
WAN (Wide Area Network)
The DSL port of the ADSL Router composes the WAN interface, which supports PPP or RFC 1483 connecting to another remote DSL device.
