Network Services Acronyms : Need to Know (Defined)
Terms in this set (96)
The IEEE standard for wireless networking.
The IEEE standard for Ethernet networking devices and data handling (using the CSMA/CD access method).
2.4 GHz band
The range of radio frequencies from 2.4 to 2.4835 GHz. The 2.4 GHz band, which allows for 11 unlicensed channels, is used by WLANs that follow the popular 802.11b and 802.11g standards. However, it is also used for cordless telephone and other transmissions, making the 2.4 GHz band more susceptible to interference than the 5-GHz band.
5 GHz band
A range of frequencies that comprises four frequency bands: 5.1 GHz, 5.3 GHz, 5.4 GHz, and 5.8 GHz. It consists of 24 unlicensed bands, each 20 MHz wide. The 5-GHz band is used by WLANs that follow the 802.11a and 802.11n standards.
802.11a The IEEE standard for a wireless networking technique that uses multiple frequency bands in the 5-GHz frequency range and provides a theoretical maximum throughput of 54 Mbps. 802.11a's high throughput, compared with 802.11b, is attributable to its use of higher frequencies, its unique method of encoding data, and more available bandwidth.
802.11b The IEEE standard for a wireless networking technique that uses DSSS (direct sequence spread spectrum) signaling in the 2.4-2.4835-GHz frequency range (also called the 2.4-GHz band). 802.11b separates the 2.4-GHz band into 14 overlapping 22-MHz channels and provides a theoretical maximum of 11-Mbps throughput.
802.11g The IEEE standard for a wireless networking technique designed to be compatible with 802.11b while using different encoding techniques that allow it to reach a theoretical maximum capacity of 54 Mbps. 802.11g, like 802.11b, uses the 2.4-GHz frequency band.
802.11n The IEEE standard for a wireless networking technique that may issue signals in the 2.4- or 5-GHz band and can achieve actual data throughput between 65 and 600 Mbps. It accomplishes this through several means, including MIMO, channel bonding, and frame aggregation. 802.11n is backward compatible with 802.11a, b, and g.
(Acknowledgment) A response generated at the Transport layer of the OSI model that confirms to a sender that its frame was received. The ACK packet is the third of three in the three-step process of establishing a connection.
(Access Control List) A list of statements used by a router to permit or deny the forwarding of traffic on a network based on one or more criteria.
A type of wireless LAN in which stations communicate directly with each other rather than through an access point (AP).
(Arithmetic Logic Unit) A digital electronic circuit that performs arithmetic and bitwise logical operations as part of a computer's CPU.
(Access Point) A device used on wireless LANs that transmits and receives wireless signals to and from multiple nodes and retransmits them to the rest of the network segment. Access points can connect a group of nodes with a network or two networks with each other. They may use directional or omnidirectional antennas.
(Application Program Interface) A set of routines that make up part of a software application.
(Automatic Private IP Addressing) A service available on computers running the Windows 98, Me, 2000, XP, Vista, Server 2003, or Server 2008 operating system that automatically assigns the computer's network interface an IP address from the range of 169.254.0.0 to 169.254.255.255 if an IP address hasn't been assigned to that interface.
(Accelerated Processing Unit) A computer CPU that includes additional accelerators, for example a GPU.
(Address Resolution Protocol) Belongs in the Network layer of the OSI model. ARP obtains the MAC (physical) address of a host, or node, and then creates a local database that maps the MAC address to the host's IP (logical) address.
(Asynchronous Transfer Mode) A telecommunications protocol in which data channels are apportioned unequally between upload speed and download speed.
(Bayonet Neill-Concelman, or British Naval Standard) A standard for coaxial cable connectors named after its coupling method and its inventors.
(Bootstrap Protocol) An Application layer protocol in the TCP/IP suite that uses a central list of IP addresses and their associated devices' MAC addresses to assign IP addresses to clients dynamically. BOOTP was the precursor to DHCP.
(Central Processing Unit) The electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions.
(Cycle Redundancy Check) An algorithm (or mathematical routine) used to verify the accuracy of data contained in a data frame.
(WIRELESS) CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) A network access method used on 802.11 wireless networks. In CSMA/CA, before a node begins to send data it checks the medium. If it detects no transmission activity, it waits a brief, random amount of time, and then sends its transmission. If the node does detect activity, it waits a brief period of time before checking the channel again. CSMA/CA does not eliminate, but minimizes, the potential for collisions.
(Ethernet) CSMA/CD (Carrier Sense Multiple Access with Collision Detection) A media access control method used most notably in local area networking using Ethernet technology. CSMA/CD is a modification of pure CSMA that is used to improve CSMA performance by terminating transmission as soon as a collision is detected, thus shortening the time required before a retry can be attempted.
(Dynamic Host Configuration Protocol) An Application layer protocol in the TCP/IP suite that manages the dynamic distribution of IP addresses on a network. Using DHCP to assign IP addresses can nearly eliminate duplicate-addressing problems.
(Demilitarized Zone) The perimeter of a protected, internal network where users, both authorized and unauthorized, from external networks can attempt to access it. Firewalls and IDS/IPS systems are typically placed in the DMZ. This might include online shopping sites.
(Domain Name System) A hierarchical way of tracking domain names and their addresses, devised in the mid-1980s. The DNS database does not rely on one file or even one server, but rather is distributed over several key computers across the Internet to prevent catastrophic failure if one or a few computers go down. DNS is a TCP/IP service that belongs to the Application layer of the OSI model.
(Digital Subscriber Line) A dedicated WAN technology that uses advanced data modulation techniques at the Physical layer to achieve extraordinary throughput over regular phone lines. DSL comes in several different varieties, the most common of which is asymmetric DSL (ADSL).
(Extensible Authentication Protocol) A Data Link layer protocol defined by the IETF that specifies the dynamic distribution of encryption keys and a preauthentication process in which a client and server exchange data via an intermediate node (for example, an access point on a wireless LAN). Only after they have mutually authenticated can the client and server exchange encrypted data. EAP can be used with multiple authentication and encryption schemes.
(Electromagnetic Interference) A type of interference that may be caused by motors, power lines, televisions, copiers, fluorescent lights, or other sources of electrical activity.
(File Transfer Protocol) Application layer protocol used to send and receive files via TCP/IP
(Hypertext Transfer Protocol) An Application layer protocol that formulates and interprets requests between Web clients and servers.
(HTTP over Secure Socket Layers) The URL prefix that indicates that a Web page requires its data to be exchanged between client and server using SSL encryption. HTTPS uses the TCP port number 443, rather than port 80 (the port that normal HTTP uses).
(Institute of Electrical and Electronics Engineers) An international society composed of engineering professionals. Its goals are to promote development and education in the electrical engineering and computer science fields.
(Internet Message Access Protocol) A mail retrieval protocol that improves on the shortcomings of POP. The single biggest advantage IMAP4 has relative to POP is that it allows users to store messages on the mail server, rather than always having to download them to the local machine. The most current version of IMAP is version 4 (IMAP4).
(Internet Protocol) A core protocol in the TCP/IP suite that operates in the Network layer of the OSI model and provides information about how and where data should be delivered. IP is the subprotocol that enables TCP/IP to internetwork.
(Internet Protocol Address) The Network layer address assigned to nodes to uniquely identify them on a TCP/IP network. IP addresses consist of 32 bits divided into four octets, or bytes.
A security attack in which an outsider obtains internal IP addresses, then uses those addresses to pretend that he has authority to access a private network from the Internet.
(Intrusion Prevention System) A dedicated device or software running on a host that automatically reacts to any unauthorized attempt to access an organization's secured resources on a network or host. IPS is often combined with IDS.
(IP Version 6) A newer standard for IP addressing that will replace the current IPv4 (IP version 4). Most notably, IPv6 uses a newer, more efficient header in its packets and allows for 128-bit source and destination IP addresses. The use of longer addresses will allow for many more IP addresses to be in circulation.
(Integrated Services Digital Network) An international standard that uses PSTN lines to carry digital signals. It specifies protocols at the Physical, Data Link, and Transport layers of the OSI model. ISDN lines may carry voice and data signals simultaneously. Two types of ISDN connections are used in North America: BRI (Basic Rate Interface) and PRI (Primary Rate Interface). Both use a combination of bearer channels (B channels) and data channels (D channels).
(Internet Service Provider) A business that provides organizations and individuals with Internet access and often, other services, such as e-mail and Web hosting.
(Local Area Network) a computer network covering a small local area, such as a home or office.
(Lightweight Directory Access Protocol) A standard protocol for accessing network directories.
(Low Earth Orbiting) A type of satellite that orbits the Earth with an altitude between 100 and 900 miles, closer to the Earth's poles than the orbits of either GEO or MEO satellites. LEO satellites cover a smaller geographical range than GEO satellites and require less power.
(Line of Sight) A wireless signal or path that travels directly in a straight line from its transmitter to its intended receiver. This type of propagation uses the least amount of energy and results in the reception of the clearest possible signal.
(Media Access Control) A 12-character string that uniquely identifies a network node. The manufacturer hard codes the MAC address into the NIC. This address is composed of the block ID and device ID.
(Medium Earth Orbiting) A type of satellite that orbits the Earth roughly 6000 to 12,000 miles above its surface, positioned between the equator and the poles. MEO satellites can cover a larger area of the Earth's surface than LEO satellites while using less power and causing less signal delay than GEO satellites.
(Multipurpose Internet Mail Extensions) MIME (Multipurpose Internet Mail Extensions) A standard for encoding and interpreting binary files, images, video, and non-ASCII character sets within an e-mail message.
(Multiple Input-Multiple Output) In the context of 802.11n wireless networking, the ability for access points to issue multiple signals to stations, thereby multiplying the signal's strength and increasing their range and data-carrying capacity. Because the signals follow multipath propagation, they must be phase-adjusted when they reach their destination.
(Multimode Fiber) A type of fiber-optic cable that contains a core with a diameter between 50 and 100 microns, through which many pulses of light generated by a light emitting diode (LED) travel at different angles.
(Mechanical Transfer-Registered Jack) A connector used with single-mode or multimode fiber-optic cable.
(Maximum Transfer Unit) The largest data unit an ethernet network will accept for transmission.
(Network Address Translation) A technique in which IP addresses used on a private network are assigned a public IP address by a gateway when accessing a public network.
(Network Interface Card) The device that enables a workstation to connect to the network and communicate with other computers. NICs are manufactured by several different companies and come with a variety of specifications that are tailored to the workstation's and the network's requirements. NICs are also called network adapters.
(Network Operating System) The software that runs on a server and enables the server to manage data, users, groups, security, applications, and other networking functions. The most popular network operating systems are Microsoft Windows NT, Windows 2000 Server, and Windows Server 2003, UNIX, Linux, and Novell NetWare.
One of the four bytes that are separated by periods and together make up an IPv4 address.
(Open System Interconnection) model A model for understanding and developing computer-to-computer communication developed in the 1980s by ISO. It divides networking functions among seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.
(Open Shortest Path First) Router protocol that checks shortest path before any other routing protocols.
(Personal Area Network) A small (usually home) network composed of personal communication devices using Bluetooth or infared.
(Port Address Translation) A form of address translation that uses TCP port numbers to distinguish each client's transmission, thus allowing multiple clients to share a limited number of Internet-recognized IP addresses.
(Private Branch Exchange) A telephone switch that connects calls within a private organization.
(Peripheral Component Interconnect Express) A high-speed serial computer expansion bus standard designed to replace the older PCI, PCI-X, and AGP bus standards. PCIe has numerous improvements over the older standards, including higher maximum system bus throughput, lower I/O pin count and smaller physical footprint, better performance scaling for bus devices, a more detailed error detection and reporting mechanism (Advanced Error Reporting, AER), and native hot-plug functionality. More recent revisions of the PCIe standard provide hardware support for I/O virtualization.
(Protocol Data Unit) A unit of data at any layer of the OSI model.
(Power Over Ethernet) Delivery of electrical current to devices using Ethernet connection cables.
(Post Office Protocol) An application-layer Internet standard protocol used by local e-mail clients to retrieve and store e-mail from a remote server over a TCP/IP connection.
(Point to Point Protocol) A communications protocol that enables a workstation to connect to a server using a serial connection. PPP can support multiple Network layer protocols and can use both asynchronous and synchronous communications. It performs compression and error correction and requires little configuration on the client workstation
PSTN / POTS
(Public Switched Telephone Network)/(Plain Old Telephone Service) The network of lines and carrier equipment that provides telephone service to most homes and businesses. Now, except for the local loop, nearly all of the PSTN uses digital transmission. Its traffic is carried by fiber-optic or copper twisted pair cable, microwave, and satellite connections.
(Permanent Virtual Circuit) A point-to-point connection over which data may follow any number of different paths, as opposed to a dedicated line that follows a predefined path. X.25, frame relay, and some forms of ATM use PVCs.
(Quality of Service) The result of specifications for guaranteeing data delivery within a certain period of time after their transmission.
(Reverse Address Resolution Protocol)Belongs in the Network layer of the OSI model. RARP relies on a RARP table to associate the IP (logical) address of a node with its MAC (physical) address. RARP can be used to supply IP addresses to diskless workstations.
(Remote Access Service) The dial-up networking software provided with Microsoft Windows client operating systems. RAS requires software installed on both the client and server, a server configured to accept incoming clients, and a client with sufficient privileges (including user name and password) on the server to access its resources. In more recent versions of Windows, RAS has been incorporated into the RRAS (Routing and Remote Access Service).
(Remote Desktop Protocol) An Application layer protocol that uses TCP/IP to transmit graphics and text quickly over a remote client-host connection. RDP also carries session, licensing, and encryption information.
(Radio Frequency Interference) A kind of interference that may be generated by broadcast signals from radio or TV towers.
(Registered Jack 11) The standard connector used with unshielded twisted pair cabling (usually Cat 3 or Level 1) to connect analog telephones.
(Registered Jack 45) The standard connector used with shielded twisted pair and unshielded twisted pair cabling.
(Round Trip Time) The length of time it takes for a packet to go from sender to receiver, then back from receiver to sender. RTT is usually measured in milliseconds.
(Subscriber/Standard Connector) A connector used with single-mode or multimode fiber- optic cable.
(Start of Frame Delimiter) A 1-byte field that indicates where the data field begins in an Ethernet frame.
(Simple Mail Transfer Protocol) The Application layer TCP/IP subprotocol responsible for moving messages from one e-mail server to another.
(Secure Shell) A cryptographic (encrypted) network protocol to allow remote login and other network services to operate securely over an insecure network. SSH was designed as a replacement for Telnet and for insecure remote shell protocols.
(Secure Sockets Layer/Transport Layer Security) is a standard security technology for establishing an encrypted link between a server and a client—typically a web server (website) and a (HTTPS: browser) or a mail server and a mail client (e.g., Outlook). SSL/TLS allows sensitive information such as credit card numbers, social security numbers, and login credentials to be transmitted securely. TLS evolved from SSL protocol and has largely superseded it, although the terms SSL or SSL/TLS are still sometimes used.
(Straight Tip) A connector used with single-mode or multimode fiber-optic cable.
(Shielded Twisted Pair) containing twisted-wire pairs that are not only individually insulated, but also surrounded by a shielding made of a metallic substance such as foil.
(Synchronization Acknowledgement) The packet node sends to acknowledge to another node that it has received a SYN request for connection. The SYN-ACK packet is the second of three in the three-step process of establishing a connection.
(Transmission Control Protocol) A core protocol of the TCP/IP suite. TCP belongs to the Transport layer and provides reliable data delivery services.
(Transmission Control Protocol/Internet Protocol) is a two-layer program. The higher layer, Transmission Control Protocol, manages the assembling of a message or file into smaller packets that are transmitted over the Internet and received by a TCP layer that reassembles the packets into the original message. The lower layer, Internet Protocol, handles the address part of each packet so that it gets to the right destination. Each gateway computer on the network checks this address to see where to forward the message. Even though some packets from the same message are routed differently than others, they'll be reassembled at the destination. TCP/IP uses the client/server model of communication in which a computer user (a client) requests and is provided a service (such as sending a Web page) by another computer (a server) in the network.
TCP/IP core protocol
Major subprotocols of the TCP/IP suite, including IP, TCP, and UDP.
A terminal emulation protocol used to log on to remote hosts using the TCP/IP protocol. Telnet resides in the Application layer of the OSI model.
(Trivial File Transfer Protocol) A TCP/IP Application layer protocol that enables file transfers between computers. Unlike FTP, TFTP relies on UDP at the Transport layer and does not require a user to log on to the remote host.
(Time to Live) A number that indicates the maximum time that a datagram or packet can remain on the network before it is discarded. Although this field was originally meant to represent units of time, on modern networks it represents the number of router hops a datagram has endured. The TTL for datagrams is variable and configurable, but is usually set at 32 or 64. Each time a datagram passes through a router, its TTL is reduced by 1. When a router receives a datagram with a TTL equal to 1, the router discards that datagram.
(User Datagram Protocol) A core protocol in the TCP/IP suite that sits in the Transport layer of the OSI model. UDP is a connectionless transport service typically used for streaming video and music. If a PDU is lost, UDP makes no attempt to recover it.
(Uniform Resource Locator) commonly informally referred to as a web address, although the terms are defined identically, is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it.
(Unshielded Twisted Pair) Ethernet cable
(Voice Over IP) The provision of telephone service over a packet-switched network running the TCP/IP protocol suite.
(Wide Area Network) Extends over a large geographical distance. Wide area networks often are established with leased telecommunication circuits. Business, education and government entities use wide area networks to relay data among staff, students, clients, buyers, and suppliers from various geographical locations. In essence, this mode of telecommunication allows a business to effectively carry out its daily function regardless of location. The Internet may be considered the largest WAN of them all.