Ad.Hoc - Ad.Hoc mode allows computers equipped with wireless transmitters and receivers to communicate directly with each other, eliminating the need for an access point.

Adapter - A 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.

AES – The Advanced Encryption Standard (AES) is a Federal Information Processing Standard (FIPS) that specifies a cryptographic algorithm for use by U.S. Government organizations to protect sensitive, unclassified information. AES is anticipated to be widely used among large and small businesses, universities and individuals outside of the U.S. Government.

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 ROM chip that are automatically executed on startup. These instructions search for the operating system, load it, and pass control to it.

Bridge - A device that interconnects different networks together.

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

Cable Modem – A device that connects a computer to the cable television network, which in turn connects to the Internet. Once connected, cable modem users have a continuous connection to the Internet. Cable modems feature asymmetric transfer rates: around 36 Mbps downstream (from the Internet to the computer), and from 200 Kbps to 2 Mbps upstream (from the computer to the Internet).

Data Packet - One frame in a packet-switched message. Most data communication is based on dividing the transmitted message into packets.
For example, an Ethernet packet can be from 64 to 1518 bytes in length.

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 centrally manage 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.

DNS - The Domain Name System (DNS) is the way that Internet domain names are located and translated into an Internet Protocol (IP) address. A domain name is a meaningful and easy-to-remember “handle” for an Internet address.
Domain - A sub network 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, and upload means transmit.

Driver - A software module that provides an interface between a network interface card and the upper-layer protocol software running in the computer; it is designed for a specific adapter, and is installed during the setup of the adapter.

DSSS (Direct-Sequence Spread-Spectrum) - DSSS generates a redundant bit pattern for each bit transmitted. This bit pattern is called a chip (or chipping code). The longer the chip, the greater the probability that the original data can be recovered. Even if one or more bits in the chip are damaged during transmission, statistical techniques embedded in the radio can recover the original data without the need for retransmission. To an unintended receiver, DSSS appears as low power wideband noise and is rejected (ignored) by most narrowband receivers.

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.

Encryption – Encryption is a mathematical operation that transforms data from “Clear Text” to “Cipher Text”, which cannot be interpreted. Usually the mathematical operation requires that an alphanumeric key be supplied along with the clear text. The key and clear text are processed by the encryption operation, which leads to data scrambling that makes it secure. Decryption is the opposite of encryption: it is the mathematical operation that transforms cipher text to clear text.

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, which 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. A firewall, working closely with a router, examines

Firmware - Programming that is inserted into programmable read-only memory, thus becoming a permanent part of a computing device.

Flash Memory - Flash memory is an electronic storage device capable of recording several megabytes of data files.
Fragmentation - Breaking a packet into smaller units when transmitting over a network medium that cannot support the original size of the packet.

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 (Institute of Electrical and Electronics Engineers) - 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 has several large societies in special areas, such as the IEEE Computer Society.

IEEE 802.11 - Industry standard that enables wireless LAN hardware from different manufacturers to communicate.
Infrastructure Mode - A mode of operation of the 802.11b wireless protocol that allows all computers on a wired and wireless network to share a peripheral, such as a printer or high speed Internet Access.

IP Address - In the most widely installed level of the Internet Protocol (IP) today, and IP address is a 32-binary digit number that identifies each sender or receiver of information that is sent in packets 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 utility that provides for querying, defining and managing IP addresses within a network. This utility is commonly used under Windows NT and 2000, for configuring networks with a static IP address.

IPSec (Internet Protocol Security) - A developing standard for security at the network or packet-processing layer of network communication. A big advantage of IPSec is that security arrangements can be handled without requiring changes to individual user computers.

IRQ (Interrupt Request) – A hardware interrupt on a PC. There are 16 IRQ lines used to signal the CPU that a peripheral event has started or terminated. Except for PCI devices, two devices cannot use the same line.

ISP (Internet Service Provider) - A company that provides individuals and companies access to the Internet and other related services such as website building and virtual hosting.

LAN (Local Area Network) – 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).

Latency - The time delay between when the first bit of a packet is received and the last bit is forwarded.

Link Quality - The quality of data being received.

MAC Address (Media Access Control Address) - A unique number assigned by the manufacturer to any Ethernet networking device, such as a network adapter, that allows the network to identify it at the hardware level.

Mbps (Megabits per Second) – One million bits per second; a unit of measurement of the speed of data transmission.

NAT (Network Address Translation) – 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.

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 Filtering - Discarding unwanted network traffic based on its originating address or range of addresses or its type (e-mail, file transfer, etc.).

PCI (Peripheral Component Interconnect) – A peripheral bus commonly used in PCs, Macintoshes and workstations. It was designed primarily by Intel and first appeared on PCs in late 1993. PCI provides a high-speed data path between the CPU and peripheral devices (video, disk, network, etc.). There are typically three of four PCI slots on the motherboard. In a Pentium PC, there is generally a mix of PCI and ISA slots or PCI and EISA slots. Early on, the PCI bus was known as a “local bus.” PCI allows IRQs to be shared, which helps to solve the problem of limited IRQs available on a PC. For example, if there were only one IRQ left over after ISA devices were given their required IRQs, all PCI devices could share it. In a PCI-only machine, there cannot be insufficient IRQs, as all can be shared.

PCMCIA - The PCMCIA (Personal Computer Memory Card International Association) is an industry group organized in 1989 to promote standards for a credit card-size memory or I/O device that would fit into a personal computer, usually a notebook or laptop computer.

Peer-to-Peer Networking – Allows users to share local resources between PCs without needing an access point or router.

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.

Plug-and-Play – The ability of a computer system to configure expansion boards and other devices automatically without requiring the user to turn off the system during installation.

Port – A pathway into and out of the computer of 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) – A method used mostly by DSL providers for connecting personal computers to a broadband modem for Internet access. It is similar to how a dial-up connection works but at higher level.

PPTP (Point-to-Point Tunneling Protocol) – A protocol (set of communication rules) that allows corporations to extend their own corporate network through private “tunnels” over the public Internet. Effectively, a corporation uses a wide-area network as a single large local area network. A company no longer needs to lease its own lines for wide-area communication but can securely use the public networks. This kind of interconnection is known as a virtual private network (VPN).

Print Server - A hardware device that enables a printer to be located anywhere in the network.

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 and is known to waste bandwidth. AppleTalk, DECnet, TCP/IP, NetWare, and VINES all use incompatible versions of RIP.

RJ-11 (Registered Jack-11) – A telephone connector that holds up to six wires. The RJ-11 is the common connector used to plug a telephone into a wall.

RJ-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 sub networks together. Routers are useful in breaking down a very large network into smaller sub networks; they introduce longer delays and typically have much lower throughput rates than bridges.

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

Signal Strength – The amount of electromagnetic energy is present. A receiver (such as the one in your access point determines the strength of the signal for each wireless channel.

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.

SOHO (Small Office/Home Office) – Market segment of professionals who work at home or in small offices.

SPI (Stateful Packet Inspection) – SPI is a technology used in firewalls which will look at each individual packet for information such as it’s source and destination addresses and the protocol that is being used, in order to take certain actions based upon a set of pre-established criteria. SPI can be used to prevent DoS attacks, since the contents within the packet are known.

Static IP Address - A permanent IP address that is assigned to a node in 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.

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 form 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 Internet Protocol (IP) to send data in the form of message units between computers over the Internet. While IP takes care of handling the actual delivery of the data, TCP keeps track of the individual units of data (called packets) that a message is divided into for efficient routing through the Internet.

TCP/IP (Transmission Control Protocol/Internet Protocol) - The basic communication language or protocol of the Internet. It can also be used as a communication protocol in a private network (either an intranet or an extranet). When you are set up with access to the Internet, your computer is uses the TCP/IP protocol.

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.

UDP (User Datagram Protocol) – A communications method (protocol) that offers a limited amount of service when messages are exchanged between computers in a network that uses the Internet Protocol (IP). UDP is an alternative to the Transmission Control Protocol (TCP) and, together with IP, is sometimes referred to as UDP/IP. Like the Transmission Control Protocol, UDP uses the Internet Protocol to actually get a data unit (called a datagram) from one computer to another. Unlike TCP, however, UDP does not provide the service of dividing a message into packets (datagrams) and reassembling it at the other end. Specifically, UDP doesn’t provide sequencing of the packets that the data arrives in. This means that the application program that uses UDP must be able to make sure that the entire message has arrived and is in the right order. Network applications that want to save processing time because they have very small data units to exchange (and therefore very little message reassembling to do) may prefer UDP to TCP.

Upgrade – To replace existing software of firmware with a newer version.

Upload – To send a file transmitted over a network. In a communications session, upload means transmit, and 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.

VLAN (Virtual LAN) – A logical association that allows users to communicate as if they were physically connected to a single LAN, independent of the actual physical configuration of the network.

WAN (Wide-Area Network) - A communications network that covers a wide geographic area, such as a state or country.

WEP (Wired Equivalent Privacy) – A data privacy mechanism based on 64-bit and 128-bit shared key algorithms, as described in the IEEE802.11 standard.

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.