10baset - an ethernet standard that uses twisted wire pairs.

    100basetx - ieee physical layer specification for 100 mbps over two pairs of category 5 utp or stp wire.

    adapter - printed circuit board that plugs into a pc to add to capabilities or connectivity to a pc. in a networked environment, a network interface card (nic) is the typical adapter that allows the pc or server to connect to the intranet and/or internet.

    auto-negotiate - to automatically determine the correct settings. the term is often used with communications and networking. for example, ethernet 10/100 cards, hubs and switches can determine the highest speed of the node they are connected to and adjust their transmission rate accordingly. backbone — the part of a network that connects most of the systems and networks together and handles the most data.

    bandwidth - the transmission capacity of a given facility, in terms of how much data the facility can transmit in a fixed amount of time; expressed in bits per second (bps).

    bit - a binary digit. the value —0 or 1—used in the binary numbering system. also, the smallest form of data.

    boot - to cause the computer to start executing instructions. personal computers contain built-in instructions in a rom chip that are automatically executed on startup. these instructions search for the operating system, load it and pass control to it.

    broadband - a data-transmission scheme in which multiple signals share the bandwidth of a medium. this allows the transmission of voice, data and video signals over a single medium. cable television uses broadband techniques to deliver dozens of channels over one cable.

    browser - a browser is an application program that provides a way to look at and interact with all the information on the world wide web or pc. the word "browser" seems to have originated prior to the web as a generic term for user interfaces that let you browse text files online.

    csma/cd (carrier sense multiple access/collision detection) - the lan access method used in ethernet. when a device wants to gain access to the network, it checks to see if the network is quiet (senses the carrier). if it is not, it waits a random amount of time before retrying. if the network is quiet and two devices access the line at exactly the same time, their signals collide. when the collision is detected, they both back off and each wait a random amount of time before retrying.

    database - a database is a collection of data that is organized so that its contents can easily be accessed, managed, and updated.

    default gateway - the routing device used to forward all traffic that is not addressed to a station within the local subnet.

    dhcp (dynamic host configuration protocol) - a protocol that lets network administrators manage centrally and automate the assignment of internet protocol (ip) addresses in an organization's network. using the internet's set of protocol (tcp/ip), each machine that can connect to the internet needs a unique ip address. when an organization sets up its computer users with a connection to the internet, an ip address must be assigned to each machine.

    without dhcp, the ip address must be entered manually at each computer and, if computers move to another location in another part of the network, a new ip address must be entered. dhcp lets a network administrator supervise and distribute ip addresses from a central point and automatically sends a new ip address when a computer is plugged into a different place in the network.

    dhcp uses the concept of a "lease" or amount of time that a given ip address will be valid for a computer. the lease time can vary depending on how long a user is likely to require the internet connection at a particular location. it's especially useful in education and other environments where users change frequently. using very short leases, dhcp can dynamically reconfigure networks in which there are more computers than there are available ip addresses.

    dhcp supports static addresses for computers containing web servers that need a permanent ip address.

    diffie-hellman - a public key management system used by most vpn devices and software applications. this system uses public and private keys to generate a "shared secret," a cryptographic key shared by both endpoints of a vpn tunnel. using this shared secret, one endpoint encrypts a symmetric key and transmits it to the other endpoint. both endpoints then use this symmetric key to encrypt and decrypt data transmissions. with diffie-hellman, users do not need to know the specific value of the symmetric key, and symmetric key changes are transparent to the users. (key changes help increase security.) for more information, visit the website of the internet engineering task force, www.ietf.org.

    dmz - (demilitarized zone) allows one ip address (or computer) to be exposed to the internet. some applications require multiple tcp/ip ports to be open. it is recommended that you set your computer with a static ip address if you want to use dmz hosting.

    dns - the domain name system (dns) is the way that internet domain name are located and translated into internet protocol (ip) addresses. a domain name is a meaningful and easy-to-remember "handle" for an internet address.

    domain - a subnetwork comprised of a group of clients and servers under the control of one security database. dividing lans into domains improves performance and security.

    download - to receive a file transmitted over a network. in a communications session, download means receive, upload means transmit.

    dynamic ip address - an ip address that is automatically assigned to a client station in a tcp/ip network, typically by a dhcp server. network devices that serve multiple users, such as servers and printers, are usually assigned static ip addresses.

    dynamic routing - the ability for a router to forward data via a different route based on the current conditions of the communications circuits. for example, it can adjust for overloaded traffic or failing lines and is much more flexible than static routing, which uses a fixed forwarding path.

    ethernet - ieee standard network protocol that specifies how data is placed on and retrieved from a common transmission medium. has a transfer rate of 10 mbps. forms the underlying transport vehicle used by several upper-level protocols, including tcp/ip and xns.

    fast ethernet - a 100 mbps technology based on the 10base-t ethernet csma/cd network access method.

    firewall - a firewall is a set of related programs, located at a network gateway server, that protects the resources of a network from users from other networks. (the term also implies the security policy that is used with the programs.) an enterprise with an intranet that allows its workers access to the wider internet installs a firewall to prevent outsiders from accessing its own private data resources and for controlling what outside resources to which its own users have access.

    basically, a firewall, working closely with a router, examines each network packet to determine whether to forward it toward its destination.

    firmware - code that is written onto read-only memory (rom) or programmable read-only memory (prom). once firmware has been written onto the rom or prom, it is retained even when the device is turned off.

    fqdn (fully qualified domain name) - the host name and domain name for a specific computer on the internet. for example, www.linksys.com is a fqdn.

    the host name is "www", and the domain name is "linksys.com".

    ftp (file transfer protocol) - a protocol used to transfer files over a tcp/ip network (internet, unix, etc.). for example, after developing the html pages for a web site on a local machine, they are typically uploaded to the web server using ftp.

    ftp includes functions to log onto the network, list directories and copy files.

    it can also convert between the ascii and ebcdic character codes. ftp operations can be performed by typing commands at a command prompt or via an ftp utility running under a graphical interface such as windows. ftp transfers can also be initiated from within a web browser by entering the url preceded with ftp://.

    unlike e-mail programs in which graphics and program files have to be "attached," ftp is designed to handle binary files directly and does not add the overhead of encoding and decoding the data.

    full duplex - the ability of a device or line to transmit data simultaneously in both directions.

    gateway — a device that interconnects networks with different, incompatible communications protocols.

    half duplex - data transmission that can occur in two directions over a single line, but only one direction at a time.

    hardware - hardware is the physical aspect of computers, telecommunications, and other information technology devices. the term arose as a way to distinguish the "box" and the electronic circuitry and components of a computer from the program you put in it to make it do things. the program came to be known as the software.

    hub - the device that serves as the central location for attaching wires from workstations. can be passive, where there is no amplification of the signals; or active, where the hubs are used like repeaters to provide an extension of the cable that connects to a workstation.

    ieee - the institute of electrical and electronics engineers. the ieee describes itself as "the world's largest technical professional society—promoting the development and application of electrotechnology and allied sciences for the benefit of humanity, the advancement of the profession, and the wellbeing of our members."

    the ieee fosters the development of standards that often become national and international standards. the organization publishes a number of journals, has many local chapters, and several large societies in special areas, such as the ieee computer society.

    ip address - in the most widely installed level of the internet protocol (internet protocol) today, an ip address is a 32-binary digit number that identifies each sender or receiver of information that is sent in packet across the internet. when you request an html page or send e-mail, the internet protocol part of tcp/ip includes your ip address in the message (actually, in each of the packets if more than one is required) and sends it to the ip address that is obtained by looking up the domain name in the uniform resource locator you requested or in the e-mail address you're sending a note to. at the other end, the recipient can see the ip address of the web page requestor or the e-mail sender and can respond by sending another message using the ip address it received.

    ipconfig - a windows nt or 2000 utility that provides for querying, defining and managing ip addresses within a network. a commonly used utility for configuring networks with static ip addresses.

    ipsec (internet protocol security) - a suite of protocols used to implement secure exchange of packets at the ip layer. ipsec supports two basic modes: transport and tunnel. transport encrypts the payload of each packet, leaving the header untouched, while tunnel mode encrypts both the header and the pay load and is therefore more secure. ipsec must be supported on both transmitter and receiver and must share a public key. tunnel mode is widely deployed in vpns (virtual private networks).

    isp - an isp (internet service provider) is a company that provides individuals and companies access to the internet and other related services such as web site building and virtual hosting.

    lan - a local area network (lan) is a group of computers and associated devices that share a common communications line and typically share the resources of a single processor or server within a small geographic area (for example, within an office building).

    mac address - the mac (media access control) address is your computer's unique hardware number.

    mbps (megabits per second) - one million bits per second; unit of measurement for data transmission.

    mirc - mirc runs under windows and provides a graphical interface for logging onto irc servers and listing, joining and leaving channels.

    nat - nat (network address translation) is the translation of an internet protocol address (ip address) used within one network to a different ip address known within another network. one network is designated the inside network and the other is the outside.

    network - a system that transmits any combination of voice, video and/or data between users.

    network mask - also known as the "subnet mask".

    nic (network interface card) - a board installed in a computer system, usually a pc, to provide network communication capabilities to and from that computer system. also called an adapter.

    packet - a unit of data routed between an origin and a destination in a network.

    ping (packet internet groper) - an internet utility used to determine whether a particular ip address is online. it is used to test and debug a network by sending out a packet and waiting for a response.

    port - a pathway into and out of the computer or a network device such as a switch or router. for example, the serial and parallel ports on a personal computer are external sockets for plugging in communications lines, modems and printers.

    pppoe (point to point protocol over ethernet) - pppoe is a method for the encapsulation of ppp packets over ethernet frames from the user to the isp over the internet. one reason pppoe is preferred by isps is because it provides authentication (username and password) in addition to data transport. a pppoe session can be initiated by either a client application residing on a pc, or by client firmware residing on a modem or router.

    pptp (point-to-point tunneling protocol) - a protocol which allows the point to point protocol (ppp) to be tunneled through an ip network. pptp does not specify any changes to the ppp protocol but rather describes a "tunneling service" for carrying ppp (a tunneling service is any network service enabled by tunneling protocols such as pptp, l2f, l2tp, and ipsec tunnel mode). one example of a tunneling service is secure access from a remote small office network to a headquarters corporate intranet via a virtual private network (vpn) that traverses the internet. however, tunneling services are not restricted to corporate environments and may also be used for personal (i.e., non-business) applications.

    rip (routing information protocol) - a simple routing protocol that is part of the tcp/ip protocol suite. it determines a route based on the smallest hop count between source and destination. rip is a distance vector protocol that routinely broadcasts routing information to its neighboring routers.

    rj-45 (registered jack-45) - a connector similar to a telephone connector that holds up to eight wires, used for connecting ethernet devices.

    router - protocol-dependent device that connects subnetworks together. routers are useful in breaking down a very large network into smaller subnetworks; they introduce longer delays and typically have much lower throughput rates.

    server - any computer whose function in a network is to provide user access to files, printing, communications, and other services.

    software - instructions for the computer. a series of instructions that performs a particular task is called a "program." the two major categories of software are "system software" and "application software." system software is made up of control programs such as the operating system and database management system (dbms). application software is any program that processes data for the user.

    a common misconception is that software is data. it is not. software tells the hardware how to process the data.

    static ip address - a permanent ip address that is assigned to a node in an ip or a tcp/ip network.

    static routing - forwarding data in a network via a fixed path. static routing cannot adjust to changing line conditions as can dynamic routing.

    stp (shielded twisted pair) - telephone wire that is wrapped in a metal sheath to eliminate external interference.

    subnet mask - the method used for splitting ip networks into a series of subgroups, or subnets. the mask is a binary pattern that is matched up with the ip address to turn part of the host id address field into a field for subnets.

    switch - 1. a data switch connects computing devices to host computers, allowing a large number of devices to share a limited number of ports. 2. a device for making, breaking, or changing the connections in an electrical circuit.

    tcp (transmission control protocol) - a method (protocol) used along with the ip (internet protocol) to send data in the form of message units (datagram) between network devices over a lan or wan. while ip takes care of handling the actual delivery of the data (routing), tcp takes care of keeping track of the individual units of data (called packets) that a message is divided into for efficient delivery over the network. tcp is known as a "connection oriented" protocol due to requiring the receiver of a packet to return an acknowledgment of receipt to the sender of the packet resulting in transmission control.

    tcp/ip (transmission control protocol/internet protocol) - the basic communication language or set of protocols for communications over a network (developed specifically for the internet). tcp/ip defines a suite or group of protocols and not only tcp and ip.

    tftp (trivial file transfer protocol) - a version of the tcp/ip ftp protocol that has no directory or password capability.

    throughput - the amount of data moved successfully from one place to another in a given time period.

    topology - a network's topology is a logical characterization of how the devices on the network are connected and the distances between them. the most common network devices include hubs, switches, routers, and gateways.

    most large networks contain several levels of interconnection, the most important of which include edge connections, backbone connections, and wide-area connections.

    upgrade - to replace existing software or firmware with a newer version.

    upload - to transmit a file over a network. in a communications session, upload means transmit, download means receive.

    url (uniform resource locator) - the address that defines the route to a file on the web or any other internet facility. urls are typed into the browser to access web pages, and urls are embedded within the pages themselves to provide the hypertext links to other pages.

    udp (user datagram protocol) - a method (protocol) used along with the ip (internet protocol) to send data in the form of message units (datagram) between network devices over a lan or wan. while ip takes care of handling the actual delivery of the data (routing), udp takes care of keeping track of the individual units of data (called packets) that a message is divided into for efficient delivery over the network. udp is known as a "connection-less" protocol due to not requiring the receiver of a packet to return an acknowledgment of receipt to the sender of the packet (as opposed to tcp).

    utp - unshielded twisted pair is the most common kind of copper telephone wiring. twisted pair is the ordinary copper wire that connects home and many business computers to the telephone company. to reduce crosstalk or electromagnetic induction between pairs of wires, two insulated copper wires are twisted around each other. each signal on twisted pair requires both wires.

    since some telephone sets or desktop locations require multiple connections, twisted pair is sometimes installed in two or more pairs, all within a single cable.

    vpn (virtual private network) - a technique that allows two or more lans to be extended over public communication channels by creating private communication subchannels (tunnels). effectively, these lans can use a wan as a single large "virtually private" lan. this removes the need to use leased lines for wan communications through secure use of a publicly available wan (such as the internet). examples of vpn technology are: pptp (point to point tunneling protocol), l2tp (layer 2 tunneling protocol), and ipsec (internet protocol security).

    wan (wide area network)- a communications network that covers a relatively large geographic area, consisting of two or more lans. broadband communication over the wan is often through public networks such as the telephone (dsl) or cable systems, or through leased lines or satellites. in its most basic definition, the internet could be considered a wan.

    winipcfg - configuration utility based on the win32 api for querying, defining and managing ip addresses within a network. a commonly used utility for configuring networks with static ip addresses.

    workgroup - two or more individuals that share files and databases.