All Networking + Terms

cable tester

A device that tests cables for one or more of the following conditions: continuity, segment length, distance to a fault, attenuation along a cable, near-end cross-talk, and termination resistance and impedance.

AP (access point)

A device used on wireless LANs that accepts wireless signals from multiple nodes and retransmits them to the rest of the network.

BCP (business continuity plan)

A document that details how an organization intends to maintain busi-ness operations during a disaster.

BiDi transceiver

A fiber-optic transceiver that supports bidirectional transmission on both its ports.

badge

A form of identification that includes the person's name and perhaps a photo, title, or other information.

AS (autonomous system)

A group of networks, often on the same domain, that are operated by the same organization.

bridged mode

A type of network connection in which a vNIC accesses a physical network using the host machine's NIC. The bridged vNIC obtains its own IP address, default gateway, and subnet mask infor-mation from the physical LAN's DHCP server.

BPDU (Bridge Protocol Data Unit)

A type of network message that transmits STP information between switches.

ad hoc

A type of wireless LAN in which stations communicate directly with each other (rather than using an access point).

BRI (Basic Rate Interface)

A variety of ISDN that uses two 64-Kbps B channels and one 16-Kbps D channel, as summarized by the notation 2B1D.

bandwidth speed tester

A website that tests the current upload and download speeds on a WAN connection.

BLE (Bluetooth Low Energy)

Also called Bluetooth Smart, a new version of Bluetooth that provides a range comparable to the earlier version of Bluetooth, but that consumes less power.

BootP (Boot Protocol/Bootstrap Protocol)

An IP network protocol that automatically boots a system and assigns an IP address without user involvement.

cable broadband

Broadband Internet access provided over the coaxial cable wiring used for TV signals.

BGP (Border Gateway Protocol)

Dubbed the "protocol of the Internet," this path- vector routing protocol is the only current EGP and is capable of considering many factors in its routing metrics.

alien crosstalk

Electromagnetic interference induced on one cable by signals traveling over a nearby cable.

BSSID (basic service set identifier)

In IEEE termi-nology, the identifier for a BSS (basic service set).

BSS (basic service set)

In IEEE terminology, a group of stations that share an access point.

authenticator

In Kerberos authentication, the user's time stamp encrypted with the session key. The authenticator is used to help the service verify that a user's ticket is valid.

bit rate

In digital transmissions, a measurement of throughput and bandwidth that is expressed as bits transmitted per second.

AH (authentication header)

In the context of IPsec, a type of encryption that provides authentication of the IP packet's data payload through public key techniques.

accounting

In the context of network security, the process of logging users' access and activities on a network.

beacon frame

In the context of wireless network-ing, a frame issued by an access point to alert other nodes of its existence.

association

In the context of wireless networking, the communication that occurs between a wireless client and an access point enabling the client to connect to the network via that access point.

automatic failover

In the event of a component failure, the ability of a redundant component to immediately assume the duties of the failed component.

broadcast domain

Logically grouped network nodes that can communicate directly via broadcast transmissions. By default, switches and repeating devices, such as hubs, extend broadcast domains. Routers and other Layer 3 devices separate broadcast domains.

B channel

The "bearer" channel that employs circuit-switching techniques to carry voice, video, audio, and other types of data over an ISDN connection.

AD DS (Active Directory Domain Services)

The Active Directory service that manages the process allowing a user to sign on to a network from any computer on the network and get access to the resources that Active Directory manages.

APC (Angle Polished Connector)

The latest advancement in ferrule technology that uses the principles of reflection to its advantage by placing the end faces of the highly polished ferrules at an angle to each other, thus reducing the effect of back reflection.

attenuation

The loss of a signal's strength as it travels away from its source.

best path

The most efficient route from one node on a network to another, as calculated by a router.

ADSL (asymmetric DSL)

The most popular variation of DSL and offers faster download speeds than upload speeds.

AUP (acceptable use policy)

The portion of a security policy that explains to users what they can and cannot do while accessing a network's resources, and penalties for violations. It might also describe how these measures protect the network's security.

BYOD (bring your own device)

The practice of allowing people to bring their smartphones, laptops, or other technology into a facility for the purpose of performing work or school responsibilities.

API (application programming interface) call

The process an application uses to make a request of the OS.

authentication

The process of comparing and matching a client's credentials with the credentials in a client database to enable the client to log on to the network.

address translation

The process of substituting a private IP address used by computers on a private network with the public IP address of a gateway device or router when these computers need access to other networks or the Internet.

authorization

The process that determines what a user can and cannot do with network resources.

Application layer

The seventh layer of the OSI model. Application layer protocols enable software programs to negotiate formatting, procedural, security, synchronization, and other requirements with the network.

canonical name

The true name of a server, such as www.example.com, as opposed to one of many alias names a server might have, such as ns1.example.com.

asynchronous

(1) A characteristic of transmission technology that offers faster download speeds than upload speeds. (2) A communications method in which nodes do not have to conform to any predetermined schemes that specify the timing of data transmissions.

ARP table

A database of records that maps MAC addresses to IP addresses. The ARP table is stored on a computer's hard disk where it is used by the ARP utility to supply the MAC addresses of network nodes, given their IP addresses.

cable modem

A device that modulates and demodulates signals for transmission and reception via cable wiring.

AF (Assured Forwarding)

A DiffServ forwarding specification that prioritizes data handling, but provides no guarantee that on a busy network messages will arrive on time and in sequence.

ATM (Asynchronous Transfer Mode)

A WAN technology functioning primarily at Layer 2 that delivers data using fixed-size packets, called cells.

broadband

A WAN technology where the cables and available bandwidth are shared between multiple customers.

asset tracking tag

A barcode or wireless-enabled transmitter used to track the movement or condition of equipment, inventory, or people.

ASP (application service provider)

A business that provides software services over the Internet.

AAA (authentication, authorization, and accounting

A category of protocols that establish a client's identity, authorize a user for certain privileges on a system or network, and keep an account of the client's system or network usage.

asymmetrical

A characteristic of transmission technology that offers faster download speeds than upload speeds.

BNC (British Naval Connector/Bayonet Neill-Concelman) connector

A coaxial cable connector type that uses a turn-and-lock (or bayonet) style of coupling.

backup

A copy of data or program files created for archiving or safekeeping.

ARP (Address Resolution Protocol)

A core protocol in the TCP/IP suite that belongs in the Data Link layer of the OSI model. ARP works in conjunction with IPv4 to discover the MAC address of a node on the local network and to maintain a database that maps local IP addresses to MAC addresses.

ACL (access control list)

A list of statements used by a router or other device to permit or deny the forwarding of traffic on a network based on one or more criteria.

ANDing

A logical process of combining bits.

Bluetooth

A low-power wireless technology that provides close-range communication between devices such as PCs, smartphones, tablets, and accessories.

availability

A measure of how consistently and reliably a file, device, or connection can be accessed by authorized personnel.

alert

A message generated when a pre-defined event occurs, which is then logged by the system.

broadcast

A message that is read by every node on a network.

APT (advanced persistent threat or advanced persistent tool)

A network attack that continues undetected for a long period of time.

CAN (campus area network)

A network of connected LANs within a limited geographical area, such as the buildings on a university campus.

ARIN (American Registry for Internet Numbers)

A nonprofit corporation that manages the distribution of public IP addresses for the North American region, including the United States, Canada, and several small islands, countries, and territories in that region (including in the Caribbean). ARIN also services Antarctica.

AD (administrative distance)

A number indicating a protocol's reliability, with lower values being given higher priority. This assignment can be changed by a network administrator.

AES (Advanced Encryption Standard)

A private key encryption algorithm that uses a sophisticated family of ciphers along with multiple stages of data transformation.

baseline

A record of how a network operates under normal conditions.

border router

A router that connects an autonomous system with an outside network—for example, the router that connects a business to its ISP. Also called edge router.

caching DNS server

A server that accesses public DNS data and caches the DNS information it collects.

APIPA (Automatic Private IP Addressing)

A service available on Windows computers that automatically assigns the computer's NIC a link-local IPv4 address in the range of 169.254.0.1 through 169.254.255.254.

CaaS (Communication as a Service)

A service model in which communication services are provided virtually, such as VoIP or video conferencing.

BPDU guard

A software configuration on a switch's access ports that blocks certain types of BPDUs from being sent to or received by the devices, such as workstations and servers, connected to these ports.

BPDU filter

A software configuration that can be used to disable STP on specific ports, such as the port leading to the network's demarc. A BPDU filter prevents access to network links that should not be considered when plotting STP paths in a network.

agent

A software routine that collects data about a managed device's operation or compliance with security benchmarks, and provides this information to a network management application.

back door

A software security flaw that can allow unauthorized users to gain access to a system.

CAM (content addressable memory)

A special kind of high-speed computer memory often used in routers and switches for table lookup functions.

ASIC (application specific integrated circuit)

A specialized microchip designed to provide customized features to a specific application.

band

A specific frequency range on the wireless spectrum.

BERT (bit-error rate test)

A test that measures the bit-error rate of a transmission, which is the percentage of bits with errors in a transmission.

bus topology

A topology in which a single cable connects all nodes on a network without intervening connectivity devices.

bidirectional

A transmission method that allows each fiber cable to carry data in both directions.

cable performance tester

A troubleshooting tool that tests cables for continuity, but can also measure crosstalk, attenuation, and impedance; identify the location of faults; and store or print cable testing results. Also called line tester, certifier, or network tester.

A (Address) record

A type of DNS data record that maps the IPv4 address of an Internet-connected device to its domain name.

AAAA (Address) record

A type of DNS data record that maps the IPv6 address of an Internet-connected device to its domain name. Pronounced "quad-A record."

anycast address

A type of IPv6 address that represents a group of interfaces, any one of which (and usually the first available of which) can accept a transmission. At this time, anycast addresses are not designed to be assigned to hosts, such as servers or workstations, but rather to routers.

asymmetric encryption

A type of encryption (such as public key encryption) that uses a different key for encoding data than is used for decoding the cipher text.

ARP poisoning

An attack in which attackers use fake ARP replies to alter ARP tables in a network.

amplified DRDoS attack

An attack instigated using small, simple requests that trigger very large responses from the target. DNS, NTP, ICMP, LDAP, and SNMP lend themselves to being used in these kinds of attacks.

brute force attack

An attempt to discover an encryption key or password by trying numerous possible character combinations until the correct combination is found.

agentless authentication

An authentication process in which the user is authenticated rather than the device. The device is then scanned to determine compliance with access control requirements.

ANT+

An open-source wireless technology that gathers and tracks information from sensors typically embedded in heart rate monitors, GPS devices, and other activity monitoring devices.

CA (certificate authority)

An organization that issues and maintains digital certificates as part of the PKI (public-key infrastructure).

access control

One or more security techniques for managing users' access to a network and its resources.

business continuity

The ability of a company to continue doing business with the least amount of interruption possible after a major outage or other disaster.

bandwidth

The amount of data that could theoreti-cally be transmitted during a given period of time.

authentication server

The authority on computer names and their IP addresses for computers in their domains.

authoritative server

The authority on computer names and their IP addresses for computers in their domains.

backbone

The central conduit of a network that connects network segments and significant shared devices (such as routers, switches, and servers) and is sometimes referred to as "a network of networks."

AD (Active Directory)

The centralized directory database that contains user account information and security for the entire group of computers on a network.

captive portal

The first page displayed by a client's browser when the client connects to a guest network. This page usually requires the user to agree to a set of terms and conditions before gaining further access to the guest network.

access port

The interface on a switch used for an end node. Devices connected to access ports are unaware of VLAN information.

biometrics

Unique physical characteristics of an individual, such as the color patterns in his iris or the geometry of his hand.