Network Technology Glossary

This glossary contains network technology terminology present on our webpages and in our marketing and support documents.

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Access Control List; policies that determine which LAN endpoints can place and receive calls.
American National Standards Institute; the primary organization for fostering the development of technology standards in the United States.
Abstract Syntax Notation One; a language that defines the way data is sent across dissimilar communication systems. Ensures that the data received is the same as the data transmitted by providing a common syntax for specifying Application layer (program-to-program communications) protocols.
Address Resolution Protocol; protocol to automatically map IP addresses to hardware MAC addresses.
Command Line Interface; a user interface in which you type commands instead of choosing them from a menu or selecting an icon.

Dynamic Host Configuration Protocol; a protocol that assigns unique IP addresses to devices, then releases and renews these addresses as devices leave and rejoin the network.
Domain Name Server; a system for converting hostnames and domain names into IP addresses on the Internet or on local networks that use the TCP/IP protocol.

A backup operation that automatically switches to a standby database, server, or network if the primary system fails or is temporarily shut down. For example, if the master active500EM goes down, a backup active500EM in the cluster mode will take over the functions of the unit that is no longer operational.
Fiber Distributed Data Interface; a set of ANSI and ISO standards for data transmission on fiber optic lines in a local area network (LAN) that can extend in range up to 200 km (124 miles).
Fully Qualified Domain Name; the portion of an Internet Uniform Resource Locator (URL) that fully identifies the server program that an Internet request is addressed to. Includes the second-level domain name (such as ? and any other levels (for example, ? or ? The prefix ?http://? added to the fully-qualified domain name completes the URL.
File Transfer Protocol; an application layer protocol that uses TCP to transfer data ?les between machines or hosts.

Hypertext Transfer Protocol; protocol for transferring Web pages.
HTTP over SSL; protocol enabling the secured transmission of Web pages.

Internet Control Message Protocol; extension of the Internet Protocol (IP) used to generate message and control packets.
Internet Key Exchange; an IPsec (Internet Protocol Security) standard protocol used to ensure security for virtual private network (VPN) negotiation and remote host or network access.
Internet Protocol; a packet-based protocol for delivering data across networks.
Internet Protocol Security; protocol used to secure traf?c across an IP network.
A worldwide federation of national standards bodies from some 100 countries, with one standards body representing each member country.

Local Area Network; a group of computers and associated devices that share a common communications line or wireless link. Typically, connected devices share the resources of a single processor or server within a small geographic area (for example, within an office building). Usually, the server has applications and data storage that are shared in common by multiple computer users. The network may serve as few as two or three users (for example, in a home network) or as many as thousands of users (for example, in an FDDI network).

Media Access Control address; a unique numeric code that is permanently assigned to each unit of most types of networking hardware, such as access controllers, by the manufacturer at the factory.
Management Information Base; a hierarchical database used by the simple network management protocol (SNMP) to describe the particular device being monitored. MIB objects are identi?ed using ASN.1 syntax.

Network Access Server; a gateway device that acts as the single point of access to a resource. The device references an authentication server to determine if access is granted.
Network Address Translation or Network Address Translator; the translation of an Internet Protocol address (IP address) used within one network to a different IP address known within another network.
Network Time Protocol; a networking protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks.

Open Shortest Path First; a protocol for exchanging routing information within a network.

Power over Ethernet; a protocol to provide power to devices like IP cameras and wireless access points via an Ethernet connection.
Point-to-point protocol; a computer network protocol used to transfer a datagram between two directly connected (point-to-point) computers.

Quality of Service; techniques used to assure a given level of performance as measured by the transmission rate and error rates.

Remote Authentication Dial-In User Service; a client/server protocol and software that enables remote authentication of users attempting to log in to the unit.
Routing Information Protocol; protocol for exchanging routing information within a network.
Real-Time Transfer Protocol; an Internet protocol standard that specifies a way for programs to manage the real-time transmission of multimedia data over either unicast or multicast network services.

Security Association; used by IKE and IPsec to determine how data is encrypted, decrypted, and authenticated by the secure gateways.
Secure Hash Algorithm (SHA); a standard algorithm that makes a larger (60-bit) message digest and is similar to MD4.
Simple Network Management Protocol; protocol to monitor and control devices in a TCP/IP network.
Simple Network Time Protocol; a simplified version of Network Time Protocol (NTP) that is used to synchronize computer clocks on a network.
Secure Shell; a network protocol that allows data to be exchanged using a secure channel between two networked devices.
Secure Socket Layer; Secure Sockets Layer (SSL) is a commonly used protocol for managing the security of a message transmission on the Internet.
Maintains the last known or current status of an application.

Transmission Control Protocol; a set of rules (protocol) used along with the Internet Protocol (IP) to send data in the form of message units between computers over the Internet.
Protocol that provides remote terminal connection service.
Trivial File Transfer Protocol; a technology for transferring files between network devices.

User Datagram Protocol; a communications protocol that offers a limited amount of service when messages are exchanged between computers in a network that uses Internet Protocol (IP).

Virtual LAN; a logical subcomponent of a physical network. It functions as a separate network to isolate its traf?c from the rest of the network.
Voice over Internet Protocol; technology that allows telephone calls to be made over computer networks like the Internet. VoIP converts analog voice signals into digital data packets and supports real-time, two-way transmission of conversations using Internet Protocol (IP).
Virtual Private Network; a network that uses a public telecommunication infrastructure, such as the Internet, to provide remote offices or individual users with secure access to their organization?s network.

Wide Area Network; communications network that uses such devices as telephone lines, satellite dishes, or radio waves to span a larger geographic area than can be covered by a LAN.
Also known as the World Wide Web or www; the collection of sites accessible through the Internet.
Web browser
A client program that initiates requests to a Web server and displays the information that the server returns.