Term 31
Area 0
Area 0 is the backbone area in OSPF routing that connects all other OSPF areas to ensure a loop-free and efficient network routing topology.
Acronym study
Terms 31–60 of 716 CCNA acronyms and key terms. Each entry includes a plain-English definition and a link to the full 800-word glossary page with exam context and practice questions.
Term 31
Area 0 is the backbone area in OSPF routing that connects all other OSPF areas to ensure a loop-free and efficient network routing topology.
Term 32
Address Resolution Protocol (ARP) is a network protocol used to map a device's IP address to its physical MAC address so data can be delivered correctly on a local network.
Term 33
ARP poisoning is a network attack where an attacker sends fake Address Resolution Protocol messages to link their MAC address with a legitimate IP address, enabling them to intercept, modify, or stop data on a local network.
Term 34
An ARP reply is a network response sent by a device to answer an ARP request, providing its MAC address so the requesting device can map an IP address to a physical hardware address on a local network.
Term 35
An ARP request is a network broadcast message sent by a device to discover the hardware (MAC) address of another device on the same local network given its IP address.
Term 36
An ARP table is a data structure stored on a network device that maps IP addresses to their corresponding MAC addresses, enabling communication within a local network.
Term 37
An Availability Set is a logical grouping of virtual machines in Azure that helps ensure high availability by distributing VMs across different physical hardware within a datacenter.
Term 38
Asymmetric encryption is a cryptographic method that uses a pair of keys—a public key for encryption and a private key for decryption—to securely exchange data without sharing a secret.
Term 39
Auto-negotiation is an Ethernet feature that allows two connected devices to automatically agree on the best possible speed and duplex mode for their link.
Term 40
A fallback method used by a device to automatically assign itself an IP address when it cannot obtain one from a DHCP server.
Term 41
An Autonomous System (AS) is a large network or group of networks under a single administrative control that presents a unified routing policy to the internet.
Term 42
Availability is the measure of how often a system or service is operational and accessible when needed, typically expressed as a percentage of uptime.
Term 43
Awk is a scripting language used for pattern scanning and text processing, commonly used in Unix and Linux environments to extract and manipulate data from files or command output.
Term 44
Azure Bastion is a fully managed PaaS service that provides secure and seamless RDP and SSH connectivity to virtual machines directly through the Azure portal without exposing public IP addresses.
Term 45
Azure Firewall is a cloud-based network security service that protects your virtual networks in Microsoft Azure by filtering traffic based on rules you define.
Term 46
The backbone area (area 0) is the central routing area in an OSPF network that all other areas must connect to for inter-area communication.
Term 47
A Backup Designated Router (BDR) is a router in an OSPF network that waits to take over as the Designated Router if the current one fails, reducing network downtime.
Term 48
Bandwidth is the maximum amount of data that can travel over a network connection in a given amount of time, usually measured in bits per second.
Term 49
A baseline is a documented starting point for the normal performance and behavior of a system, network, or component, used to detect changes and troubleshoot issues.
Term 50
A Bash script is a text file containing a sequence of commands for the Unix shell Bash, allowing users to automate repetitive tasks and streamline system administration on Linux and macOS.
Term 51
A Basic Service Set Identifier (BSSID) is the unique hardware address that identifies a specific wireless access point or a group of wireless devices communicating together.
Term 52
A bayonet-style coaxial connector used in radio frequency applications, especially for cable television and older network connections.
Term 53
BGP (Border Gateway Protocol) is the routing protocol that directs data packets across the internet by choosing the best paths between autonomous systems.
Term 54
A bit is the smallest unit of data in computing and digital communications, representing a single binary value of either 0 or 1.
Term 55
Block size is the amount of data, measured in bytes, that a system reads or writes in a single operation, affecting storage efficiency and network performance.
Term 56
A port state in Spanning Tree Protocol (STP) where the port is prevented from forwarding traffic to avoid loops in a redundant network.
Term 57
A critical system error screen displayed by Windows when it encounters a fatal issue it cannot recover from, forcing a restart.
Term 58
Bluetooth is a short-range wireless technology used to connect devices like keyboards, mice, headphones, and smartphones without cables.
Term 59
A boot loop is a computer startup failure where the device repeatedly turns on and off or restarts without ever fully loading the operating system.
Term 60
Border Gateway Protocol (BGP) is the routing protocol that directs data packets between the autonomous systems that make up the global internet.