Abstract Syntax Notation 1 (ASN.1) - A language used for defining datatypes. ASN.1 is used in OSI standards and TCP/IP network management specifications.

Access Control (SNMP) - Restriction of the operations that may be performed for a party and of the data that the party may access.

Access Mode - A MIB access level of READ-ONLY, READ-WRITE, or NONE.

Address Resolution Protocol (ARP) - A protocol that dynamically discovers the physical address of a system, given its IP address.

Address Translation - The process of translating a Network Layer to a corresponding physical address for a device.

Agent - Software that enables a device to respond to manager requests to view or update MIB data, and send traps reporting problems or significant events.

Alarm - A variable, sampling interval, and a Rising and Falling Threshold. When a threshold is crossed, an event may be triggered.

Asynchronous Transfer Mode (ATM) - A method of packaging and switching information within 53-octet cells that will be deployed for both local area network use and wide area networking.

Attachment Unit Interface (AUI) - A cable attaching a station's Ethernet NIC to a transceiver that clamps onto a coaxial cable.

Authentication - Proof of the identity of the sender of a message.

Autonomous System (AS) - A collection of routers under the control of a single administrative authority, and using a common Interior Gateway Protocol.


Basic Encoding Rules (BER) - A set of rules for translating ASN.1 values into a stream of octets to be transmitted across a network.

Big Endian - A format for the storage or transmission of data that places the most significant byte (or bit) first.

Bridge - A device that connects two or more physical network components and forwards frames which have source and destination addresses on different network components.


Carrier Sense Multiple Access with Collision Detection (CSMA/CD) - A simple media access control protocol. All stations listen to the medium. A station wanting to spend may do so if there is no signal on the medium. When two stations transmit simultaneously, both back off and retry after a random time period.

Case Diagram - A figure that tracks the flow of incoming and outgoing Protocol Data Units.

Channel - Packets that are selected by a set of filter expression, it forms a logical data stream.

Common Management Information Protocol (CMIP) - A central OSI network management protocol.

Common Management Information Services and Protocol over TCP/IP (CMOT) - A specification for using OSI management protocols on a TCP/IP network.

Cycle Redundancy Code (CRC) - A mathematical function applied to the bits in a frame, and appended to the frame. The CRC is recalculated when the frame is received. If the result differs from the appended value, then the frame is discarded.

CSMIE/CMP - Common Management Information Service Element / Common Management Information


Data Link Connection Identifier (DLCI) - In frame relay, a local numeric identifier used to name a virtual circuit.

Datagram - The IP Protocol Data Unit. More generally, a layer 3 stand-alone message.

Deprecated - Status of a MIB variable, meaning that it still is supported, but is being phased out.


Entry Status (version 1) - A table variable used to control row creation and deletion.

Event - A table entry that identifies a notification message to be sent (in an inform-request) as a result of an alarm.

Exterior Gateway Protocol (EGP) - A protocol used to advertise the set of networks that can be reached within an autonomous system. EGP enables this information to be shared with other autonomous systems.


Fiber Distributed Data Interface (FDDI) - A standard for high-speed data transfer across a dual ring.

Frame (data network) - A layer 2 Protocol Data Unit consisting of a header, (optionally) some information, and a trailer that usually includes a Frame Check Sequence.

Frame Check Sequence (FCS) - A mathematical function applied to the bits in a frame, and appended to the frame. The FCS is recalculated when the frame is received. If the result differs from the appended value, then the frame is discarded.