IT glossary: technical terms from business IT and networking explained simply

IT terms beginning with 0-9

3rd Party:	Refers to hardware or software provided by a third-party vendor.
4in6 | 6in4:	Tunnelling methods for transmitting IPv4 packets across IPv6 networks and vice versa.
6LoWPAN:	Network protocol for the transmission of IPv6 data in low-power wireless networks.

IT terms beginning with A

Access Control:	Controls access rights to IT systems and data.
Access Network:	Network segment that connects subscribers and end devices to a provider's network.
Access Point:	Network component that connects wireless devices to a wired network via Wi-Fi.
Active Directory:	Provides centralized management of users, devices, and resources.
Adapter:	Connects different devices or interfaces.
Adaptive Security Appliance (ASA):	Cisco security platform that combines firewall, VPN and access control functions in a single system.
Address Resolution Protocol (ARP):	Network protocol that maps IP addresses to the corresponding physical MAC addresses within a local network.
Advanced Encryption Standard (AES):	Standardised encryption method used to protect digital data against unauthorised access.
Advanced Persistent Threat (APT):	Targeted, long-term cyber attack on selected organisations carried out with considerable technical effort.
Alternative Cooling:	Cooling technologies for IT systems and data centres that complement or replace conventional air-based cooling methods.
Ansible:	Open-source automation tool used to configure, manage and deploy IT systems.
Anycast:	Network addressing method that sends a request to multiple equivalent servers, answered by the nearest one.
Application Layer:	Topmost layer in the OSI and TCP/IP reference models through which applications access network services.
Application Layer Gateway:	Network function that analyses traffic at application level and adapts it for firewalls or NAT.
Application Programming Interface (API):	Enables data exchange between different applications.
Artificial Intelligence for IT Operations (AIOps):	AI-powered approach for the automated monitoring, analysis and optimisation of complex IT infrastructures and IT operations.
Asset management:	Systematic management and monitoring of IT resources throughout their entire lifecycle.
Asynchronous Transfer Mode (ATM):	Transmission technology that sends data in fixed-length cells and supports defined quality of service classes.
Authoritative Zone Transfer (AXFR):	DNS mechanism for transferring a complete zone file from one authoritative DNS server to another DNS server.
Automation:	Use of technology to execute recurring processes and tasks independently with minimal manual intervention.
Autonome Systeme:	Network domains under unified routing administration, identified on the internet by their own reference number.

IT terms beginning with B

Backbone:	High-performance core area of a network that interconnects individual network segments and sites.
Backhaul:	Transmission link that connects local access networks to the core network of a network operator.
Band Steering:	Wi-Fi function that automatically directs client devices to the most suitable frequency band.
Bandwidth:	Maximum volume of data that can be transmitted over a network connection per unit of time.
Basic services:	Fundamental IT and network services that ensure the operation of higher-level applications and systems.
Bidirectional Forwarding Detection (BFD):	Network protocol for rapidly detecting connection failures between two network devices and supporting fast failover.
Bit:	Represents the smallest unit of information in computing.
Blade server:	Compact server type in which multiple modular server units operate within a shared chassis using centralised power, cooling and network connectivity.
Bluetooth Low Energy (BLE):	Wireless technology for short-range data transmission between devices with low power requirements.
Border Gateway Protocol (BGP):	Routing protocol that controls the exchange of reachability information between autonomous systems on the internet.
Botnet:	Network of compromised devices that can be remotely controlled by cybercriminals and used to conduct coordinated cyberattacks.
Bulk:	Describes the sale or purchase of products in large quantities.
Bus topology:	Network structure in which multiple devices are connected through a shared central communication cable.
Business Communication Manager (BCM):	Communication platform for small and medium-sized businesses that combines telephony and data services in one system.
Byte:	Represents a unit of digital data consisting of eight bits.

IT terms beginning with C

Captive Portal:	Web-based login page used to authenticate users or display terms of use before granting access to a Wi-Fi or network connection.
Carrier-Grade NAT (CGNAT):	Networking technology that enables internet service providers to connect multiple customer connections to the internet through a shared public IPv4 address.
Central Processing Unit (CPU):	Refers to the central processing unit of a computer.
Certificate Management:	Management of digital certificates throughout their lifecycle to support secure authentication and encrypted communication across IT systems.
Change Advisory Board (CAB):	IT service management committee responsible for assessing, prioritising and coordinating planned changes to IT systems and infrastructures.
Change Request (CR):	Formal request for a planned modification to an IT system, IT service or existing IT infrastructure.
Channel Planning:	Strategic planning and allocation of wireless channels to reduce interference and optimise Wi-Fi performance.
CIA Triad:	Fundamental information security model based on protecting the confidentiality, integrity and availability of data and IT systems.
Cisco Discovery Protocol (CDP):	Cisco network protocol for automatically discovering directly connected Cisco devices and exchanging basic device information.
Cisco Excess Program:	Programme for distributing surplus genuine Cisco hardware from excess inventory through designated sales channels.
Cisco Refresh Program:	Manufacturer programme for professionally remanufactured and tested Cisco hardware prepared for reuse in IT infrastructures.
Classless Inter-Domain Routing (CIDR):	Method for flexibly dividing and addressing IP networks independently of the fixed network classes used in earlier networking architectures.
Client-Management:	Covers the centralized management of endpoint devices.
Client-Server Model:	Network architecture in which central systems provide services or resources that connected end devices request and use.
Client-server technology:	Network architecture in which central servers provide services that are requested by clients.
Cloud Access Security Broker (CASB):	Security solution for monitoring and controlling cloud service usage while protecting data and user access.
Cloud Computing:	Provision of IT resources such as computing power, storage, applications and network services through a flexible IT infrastructure.
Cloud Hosting:	Hosting model in which websites, applications and data operate on flexibly scalable resources within a cloud infrastructure.
Cloud Networking:	Provision and management of network functions through cloud services instead of local infrastructure.
Cloud Telephony:	Telephony over the internet in which the phone system is operated as a service in a data centre.
Co-Channel Interference (CCI):	Wireless interference that occurs when multiple Wi-Fi devices or access points use the same radio channel simultaneously.
Common Gateway Interface (CGI):	Describes an interface for running programs on web servers.
Common Vulnerabilities and Exposures (CVE):	Standardised catalogue for uniquely identifying and naming publicly known security vulnerabilities in software, hardware and IT systems.
Common Vulnerability Scoring System (CVSS):	Standardised scoring system for assessing the severity of security vulnerabilities based on technical characteristics and defined evaluation criteria.
Conference system:	Technical solution for audio and video conferencing between multiple participants and locations.
Configuration Drift:	Unintended deviation of the actual configuration of IT systems from a previously defined and desired target state.
Configuration Management Database (CMDB):	Central database for the structured documentation and management of IT components and their relationships within an IT infrastructure.
Contact Center Manager (CCM):	Refers to a system for centralized management of communication solutions.
Container Network Interface (CNI):	Standardised interface for configuring and managing network connectivity for containers within container-based IT environments.
Continuous Integration/Delivery Code (CI/CD):	Automated software development approach for continuously integrating, testing and delivering code changes.
Controller:	Central instance that controls, configures and monitors connected components.
Cyber Resilience:	Ability of organisations and IT systems to withstand cyberattacks and IT disruptions while maintaining or rapidly restoring critical business operations.
Cybercrime:	Describes criminal activities involving digital technologies.
Cybersecurity:	Protection of IT systems, networks and data against cyberattacks, unauthorised access, manipulation and digital threats.

IT terms beginning with D

Data center:	Hosts IT systems and network infrastructure.
Data link layer:	Lowest layer of the OSI model responsible for the physical transmission of bits across wired or wireless transmission media.
Data Link Layer:	Second layer of the OSI model responsible for transferring data frames between directly connected devices within a network.
Data Loss Prevention:	Prevents the loss of sensitive data.
Data Loss Prevention (DLP):	Security approach for detecting and preventing the unauthorised disclosure, transfer or loss of sensitive business data.
Data Security:	Protects data from loss, manipulation, and unauthorized access.
Database Server:	Server for centrally storing, managing and providing structured data to applications, systems and users.
DDoS Attack:	Cyberattack in which numerous systems simultaneously overload an IT infrastructure with requests or network traffic, affecting its availability.
Dedicated Internet Access (DIA):	Business internet connection with dedicated bandwidth and typically symmetrical transmission speeds for reliable enterprise networks.
Device Control:	Controls access to connected devices.
DHCP Snooping:	Protects networks from unauthorized DHCP servers.
DHCPv6:	Network protocol for automatically assigning IPv6 addresses and additional network configuration information to devices in IPv6 networks.
Digital Media Player (DMP):	Refers to a platform for managing data.
Disaster Recovery:	Describes the recovery of IT systems after failures.
Disaster Recovery as a Service (DRaaS):	Provides IT disaster recovery as a cloud service.
Dispersion Compensation Units (DCU):	Optical components that compensate for signal distortion in fibre optic links and maintain transmission quality.
Domain Name System (DNS):	Translates domain names into IP addresses.
Domain Name System Security Extensions (DNSSEC):	Security extension for the Domain Name System that verifies the authenticity and integrity of DNS data using digital signatures.
Dual Inline Memory Module (DIMM):	Memory module form factor used for RAM in servers, workstations and desktop systems.
Dynamic Host Configuration Protocol (DHCP):	Network protocol for the automatic assignment of IP addresses and configuration data to end devices.

IT terms beginning with E

East-West Traffic:	Network traffic between internal systems, servers, applications or workloads within a data centre, enterprise network or cloud environment.
End-of-Life (EoL):	Product lifecycle stage in which a manufacturer announces the discontinuation or gradual withdrawal of an IT product and its associated support.
End-of-Service (EoS):	Product lifecycle stage from which certain manufacturer service and support offerings for an IT product are no longer available.
Endpoint Detection and Response (EDR):	Security solution for continuously monitoring endpoints and detecting, analysing and responding to potential cyber threats.
Endpoint Security:	Protective measures for end devices such as laptops, servers and mobile devices against malware and unauthorised access.
Enhanced Interior Gateway Routing Protocol (EIGRP):	Dynamic routing protocol for automatically calculating efficient network paths and rapidly exchanging routing information within an autonomous system.
Equal-Cost Multipath Traffic (ECMP):	Routing method for distributing network traffic across multiple equivalent paths with identical routing costs.
EtherChannel:	Cisco technology for combining multiple physical Ethernet connections into a single logical link with increased bandwidth and redundancy.
Ethernet:	Widely adopted standard for wired data transmission in local area networks.
Ethernet connection box:	Connection point of structured cabling through which end devices are linked to the network.
Ethernet Virtual Private Network (EVPN):	Networking technology for providing scalable virtual Layer 2 and Layer 3 connectivity across a shared IP-based network infrastructure.
Ethical Hacker:	IT security professional authorised to identify vulnerabilities in IT systems, networks and applications.
Exploit:	Exploits a vulnerability in software or systems.
Extended Detection and Response (XDR):	Security solution for centrally detecting, analysing and responding to cyber threats across multiple areas of an IT infrastructure.
Exterior Gateway Protokoll (EGP):	Class of protocols used to exchange routing information between different autonomous systems.

IT terms beginning with F

Failback:	Controlled process of returning operations from a backup or secondary system to the original IT system after a disruption has been resolved.
Failover:	Automatic or manual switch from a failed primary system to a redundant secondary system to maintain IT operations.
Fast Ethernet Switch:	Network switch for connecting multiple devices within a local network using Ethernet data rates of up to 100 Mbps.
Federal Office for Information Security:	German federal authority for information security and a central point of contact for cybersecurity and IT security matters.
Fiber Distributed Data Interface (FDDI):	Describes a fiber optic networking standard.
Fibre optics:	Transmission medium that carries data as light signals over long distances at high data rates.
File Sharing:	Enables the sharing of digital files.
File Transfer Protocol (FTP):	Network protocol for transferring files between client and server in IP networks.
Firewall:	Security system that inspects and filters traffic between networks according to defined rules.
Firmware:	Software permanently stored in a device that controls its basic functions and hardware interaction.
Flash Core Module:	Refers to a flash storage module for enterprise systems.
Flash Memory:	Non-volatile semiconductor memory that retains data permanently without a power supply.
Fragmentation:	Process of dividing larger data packets into smaller units for transmission across networks with limited maximum packet sizes.

IT terms beginning with G

Gateway:	Network component that connects networks using different protocols or address ranges.
Gbytes:	Unit of measurement for data volumes equivalent to approximately one billion bytes.
Geo-Redundancy:	Geographical distribution of redundant IT systems across multiple locations to maintain critical services during local failures or disruptions.
Gigabit Ethernet Switch:	Network switch for connecting multiple devices within a local network using Ethernet data rates of up to 1 Gbps per connection.
Gigahertz (GHz):	Unit of measurement for frequency, equivalent to one billion cycles per second.
GitOps:	Operational model for automated management of IT infrastructure and applications using Git repositories as the central source for configurations and changes.
Global Area Network (GAN):	Wide-reaching communications network connecting devices and networks across countries and continents.
Global System for Mobile Communications (GSM):	Refers to a mobile communication standard.
Golden Config:	Defined and validated reference configuration that serves as the target state for IT systems, network devices or applications.
Gratuitous ARP:	ARP message used by a network device to announce its own IP-to-MAC address mapping within a local network without a prior request.

IT terms beginning with H

Hacker:	Gains unauthorized access to IT systems or networks.
Hard Disk Drive (HDD):	Magnetic storage medium with rotating platters for the permanent storage of large data volumes.
Hard Disk Encryption:	Protects stored data through encryption.
Hard Drive:	Magnetic storage medium for the permanent storage of data in servers, storage systems and PCs.
Hardware:	Refers to the physical components of a computer system.
Health Checks:	Automated or scheduled checks used to monitor the availability, functionality and operational status of IT systems, applications and network services.
Heatmap:	Automated or scheduled checks used to monitor the availability, functionality and operational status of IT systems, applications and network services.
High Performance Computing (HPC):	Use of powerful computing systems to process large volumes of data and complex, computationally intensive workloads at high speed.
Host-based Intrusion Detection System (HIDS):	Monitors individual systems for security incidents.
Hosted IP telephony:	Enables telephony through a hosted IP solution.
Hot Standby Router Protocol (HSRP):	Cisco protocol providing a redundant virtual default gateway with automatic failover if the active router becomes unavailable.
HP Renew Program:	Manufacturer programme for fully remanufactured and tested HPE enterprise hardware supplied with HPE warranty and defined quality standards.
Hub:	Simple network component that forwards incoming data signals unchanged to all connected ports.
Hybrid Cloud:	Combines private and public cloud environments.

IT terms beginning with I

Identity and Access Management (IAM):	Concept for centrally managing digital identities, user accounts and access permissions across an IT infrastructure.
Identity Services Engine (ISE):	Cisco platform for centralised access control and authentication of devices and users in the network.
IEEE 802:	Family of standards for local and metropolitan area networks defining transmission and access methods.
IEEE 802.1aq:	Standard for shortest path bridging that enables parallel use of redundant paths in Ethernet networks.
IEEE 802.3ae:	Standard for Ethernet at 10 Gbit/s over fibre optic connections.
Incremental Zone Transfer (IXFR):	DNS mechanism for transferring only modified zone data between authoritative DNS servers.
InfiniBand:	High-performance interconnect technology providing high bandwidth and very low latency between servers, storage systems and compute nodes.
Information Security Management System (ISMS):	Structured management approach for systematically controlling and continuously improving information security within an organisation.
Infrastructure as a Service (IaaS):	Provides IT infrastructure as a cloud service.
Input/Output Operations Per Second (IOPS):	Measures input/output operations per second.
Insider Threat:	Security risk originating from individuals with legitimate access to an organisation's internal systems, data or resources.
Intermediate System to Intermediate System (IS-IS):	Link-state routing protocol for dynamically calculating and distributing optimal network paths across large IP networks.
Interne Gateway Protokoll (IGP):	Class of protocols used to exchange routing information within a single autonomous system.
Internet Assigned Numbers Authority (IANA):	Manages global Internet protocols and address resources.
Internet Corporation for Assigned Names and Numbers (ICANN):	Coordinates domain names and IP address spaces.
Internet Exchange Point (IXP):	Physical network infrastructure enabling direct data exchange between independent networks and internet service providers.
Internet of Things (IoT):	Network of physical devices and sensors that collect, exchange and communicate data through digital systems.
Internet Protocol (IP):	Network protocol that addresses data packets and routes them across network boundaries to their destination.
Internet Protocol Security (IPsec):	Protocol suite for the encrypted and authenticated transmission of IP data packets.
Intrusion Detection System (IDS):	Security system that monitors network and system activity for attacks and anomalies.
Intrusion Prevention System (IPS):	Security system that detects attacks in network traffic and blocks them automatically.
IP Address Management (IPAM):	Centralised management and documentation of IP addresses, subnets and associated network resources within an IT infrastructure.
IP Addressing:	System for uniquely identifying and logically addressing devices within IP-based networks.
IT security:	Entirety of technical and organisational measures protecting IT systems, data and networks.
IT Supply Chain:	Supply chain for IT products and services covering the process from manufacturing and procurement through to delivery and business use.
IT-Remarketing:	Resale of used IT hardware following testing, data erasure and technical reconditioning.

IT terms beginning with J

Jitter:	Variation in the delay of individual data packets that affects the quality of voice and video transmissions.
Jumbo Frames:	Ethernet frames with a larger payload than standard Ethernet, potentially reducing overhead when transferring large volumes of data.

IT terms beginning with K

Kubernetes:	Open-source platform for automating the deployment, scaling and management of containerised applications across distributed IT infrastructures.

IT terms beginning with L

Layer:	Describes a layer within a networking model.
Layer 2 Switch:	Network device that forwards data within a local network based on the MAC addresses of connected devices.
Layer 3 Switch:	Network device combining local network switching with IP-based routing between different networks and VLANs.
Line Card:	Modular hardware component that provides additional interfaces and transmission capacity for connecting network devices to a network.
Line Topology:	Network structure in which multiple devices are connected along a common communication path or arranged sequentially in a linear configuration.
Line-Interactive UPS:	Uninterruptible power supply that protects connected IT equipment against power failures and voltage fluctuations while automatically regulating input voltage.
Link Aggregation:	Combination of multiple physical network connections into a single logical link to provide increased bandwidth and additional redundancy.
Link Aggregation Control Protocol (LACP):	Standardised network protocol for automatically creating and managing aggregated physical connections between compatible network devices.
Link Layer Discovery Protocol (LLDP):	Vendor-neutral network protocol for automatically discovering directly connected devices and exchanging relevant device and connection information.
Link-local Multicast Name Resolution (LLMNR):	Protocol for name resolution within the local network segment without a central DNS server.
Load Balancer:	System that distributes incoming network or application requests across multiple servers or resources to balance workloads and improve availability.
Local Area Network (LAN):	Geographically limited network connecting end devices within a building or site.
Locally Administered Address (LAA):	MAC address assigned by an administrator that replaces the manufacturer's burned-in address.
Long Range Wide Area Network (LoRaWAN):	Enables low-power IoT wireless communication.

IT terms beginning with M

Mail Server:	Server system for transmitting, receiving, storing and managing electronic messages across networks and the internet.
Maintenance Window:	Scheduled period for performing maintenance, updates or technical changes to IT systems and network infrastructures.
Malware:	Describes malicious software.
Man-in-the-Middle-Attack (MITM Attack):	Cyberattack in which an attacker secretly positions themselves between two communicating parties to intercept or manipulate transmitted data.
Managed:	Term for network components and services that are centrally configured, monitored and administered.
Managed Service Providers (MSP):	Provides IT services as an external provider.
Managed Switch:	Configurable network switch providing advanced functions for centralised network control, monitoring and security.
Maximum Transmission Unit (MTU):	Maximum permitted size of a data unit that can be transmitted across a network interface or specific network path without being divided.
Mean Time to Detect (MTTD):	Metric measuring the average time between the occurrence of an IT incident or security event and its detection.
Mean Time to Repair (MTTR):	Metric measuring the average time required to resolve a failure and restore an IT system to operational condition.
Media Access Control (MAC):	Data Link Layer mechanism that controls how network devices access a shared transmission medium and identifies network interfaces.
Media Access Control Security (MACsec):	Security standard for encrypting and protecting Ethernet connections at the Data Link Layer of the OSI model.
Medium Dependent Interface (MDI):	Interface definition specifying the assignment of transmit and receive lines on Ethernet ports.
Mesh Network:	Network topology in which multiple or all nodes have additional direct connections, providing alternative communication paths between devices.
Metro Ethernet:	Ethernet-based carrier services used to connect sites within a city or region.
Metropolitan Area Network (MAN):	Network connecting sites within a city or region with high bandwidth.
Module:	Refers to a replaceable hardware or software unit.
MPLS L3VPN:	Networking technology for securely separating and connecting multiple IP networks across a shared MPLS infrastructure.
Multi Cloud:	IT strategy involving the parallel use of cloud services from multiple independent cloud providers within a shared IT infrastructure.
Multiple Spanning Tree Protocol (MSTP):	Network protocol that prevents loops in Ethernet networks by assigning multiple VLANs to different Spanning Tree instances.
Multiprotocol Label Switching (MPLS):	Method that forwards data packets through the network using short labels instead of IP addresses.
Mutual TLS (mTLS):	Security mechanism that uses digital certificates to authenticate both communication parties within an encrypted TLS connection.

IT terms beginning with N

Near-Field Communication (NFC):	Wireless radio technology for contactless data exchange between compatible devices over very short distances.
Neighbor Discovery:	Network function for automatically discovering directly reachable devices and obtaining relevant information about neighbouring systems.
Neighbor Discovery Protocol (NDP):	IPv6 protocol for discovering neighbouring network devices, resolving link-layer addresses and automatically obtaining essential network information.
Netconf:	Standardised network management protocol for automated configuration, administration and monitoring of network devices.
Netflow:	Cisco method for collecting and analysing traffic flows in networks.
NetOps:	Approach to operating and managing network infrastructures with a focus on monitoring, configuration, automation and reliable network services.
Network adapter:	Enables a device to connect to a network.
Network Address Translation (NAT):	Networking method for translating IP addresses between different networks, such as a private enterprise network and the internet.
Network Attached Storage (NAS):	Storage system that provides data over the network as a central file repository.
Network cable:	Cable used to transmit data between network components and end devices.
Network High Availability (HA):	Network concept designed to maintain high availability of network services through redundant components, connections and automatic failover mechanisms.
Network Layer:	Third layer of the OSI model responsible for logical addressing and forwarding data packets between different networks.
Network license:	Governs software usage within a network.
Network Monitoring & Observability:	Monitoring and comprehensive analysis of network conditions, traffic and performance data to identify and investigate disruptions and anomalies.
Network Operations Center (NOC):	Centralised operational unit responsible for continuously monitoring, managing and maintaining the reliable operation of networks and IT infrastructures.
Network Time Protocol (NTP):	Network protocol for automatically synchronising the system clocks of computers, servers and network devices with a common time source.
Network-based Intrusion Detection System (NIDS):	Security system that centrally inspects network traffic for attack patterns and anomalies.
North-South Traffic:	Network traffic exchanged between internal systems within a data centre or enterprise network and external networks, services or endpoints.

IT terms beginning with O

Offline UPS:	Uninterruptible power supply that powers connected devices directly from the mains during normal operation and switches to battery power in the event of a power failure.
On-Premises Solution:	IT operating model in which hardware, software and data are hosted within an organisation's own infrastructure or a self-managed data centre.
Online Certificate Status Protocol (OCSP):	Internet protocol for checking the current validity status of digital certificates with the responsible certificate authority.
Online UPS:	Uninterruptible power supply that continuously supplies connected equipment with conditioned electrical power through an inverter.
Open Shortest Path First (OSPF):	Dynamic routing protocol for automatically calculating efficient transmission paths within IP networks.
Open Source:	Describes freely available software with open source code.
OSI model:	Reference model that divides network communication into seven layers building on one another.
Overheating:	Thermal condition in which IT components exceed their intended operating temperature, potentially affecting performance, stability or hardware.
Overlay:	Virtual network layer built on top of an existing physical infrastructure to provide logical connectivity between endpoints.
Overvoltage:	Electrical voltage above the intended operating range that can damage electronic equipment or impair its functionality.

IT terms beginning with P

Packet Capture:	Recording and analysis of data packets within a network for troubleshooting, performance analysis and examination of network communications.
Packet Capture (PCAP):	Standardised file format for storing captured network packets for troubleshooting, security investigations and detailed traffic analysis.
Patch Management:	Manages the deployment of software updates.
Peer-to-Peer-Network (P2P):	Decentralised network architecture in which connected devices communicate directly and exchange resources without relying on a central server.
Peering:	Direct interconnection of independent networks to exchange data traffic without routing it through external transit networks.
Peripheral Component Interconnect (PCI):	Bus system for connecting expansion cards to the mainboard of servers and PCs.
Personal Area Network (PAN):	Short-range network for connecting personal devices and peripherals within the immediate environment.
Phishing:	Fraudulent method in which attackers use deceptive messages or websites to obtain confidential information or trigger harmful actions.
Physical Server:	Standalone hardware system providing local computing power, storage resources and network services within an IT infrastructure.
Platform as a Service (PaaS):	Provides development platforms as a cloud service.
Point-to-Point Protocol over ATM (PPPoA):	Method for carrying PPP connections over ATM-based DSL links.
Point-to-Point Protocol over Ethernet (PPPoE):	Method that establishes PPP connections over Ethernet, commonly used for DSL dial-in.
Policy-Based Routing (PBR):	Routing method for directing network traffic according to defined policies and additional criteria beyond the destination IP address.
Port Address Translation (PAT):	Method that enables multiple internal devices to share a single public IP address by using different port numbers.
Port Mirroring:	Network function that forwards a copy of traffic from selected switch ports or VLANs to a separate port for analysis and monitoring.
Port Security:	Security feature on network switches that controls and restricts which devices are permitted to access the network through a specific switch port.
Portfast:	Switch feature that activates ports immediately without the spanning tree waiting period.
Ports:	Numbered addresses through which applications and services are addressed in a network.
Power Distribution Unit:	Electrical component that distributes a central power supply across multiple devices, outlets or circuits within an IT infrastructure.
Power Management Software:	Software solution for monitoring, controlling and managing the power supply of IT systems and connected power protection equipment.
Power over Ethernet (PoE):	Method that supplies network devices with power over the data cable.
Power-Efficient Computing:	A concept for managing the energy consumption of IT systems in line with demand through the use of appropriate hardware, resource management and optimised operational processes.
Precision Time Protocol (PTP):	Network protocol for highly accurate time synchronisation between devices in local, industrial and other time-sensitive networks.
Presentation Layer:	Sixth layer of the OSI model responsible for converting and preparing data into a suitable format for communication between applications.
Private Cloud:	Cloud computing environment in which IT resources are provided exclusively for and controlled by a single organisation.
Profiling:	Automated collection and analysis of characteristics, activities or behavioural patterns to create a structured profile of users, devices or network traffic.
Proxy:	Intermediary instance that forwards and inspects requests between client and target system.
Public Cloud:	Cloud computing environment in which IT resources are provided on demand over the internet using infrastructure operated by an external provider.
Public Switched Telephone Network (PSTN):	Global public telephone network for transmitting and switching voice connections between telephone subscribers.
Public-Key-Infrastruktur (PKI):	System of technologies, processes and trusted authorities for issuing, managing, distributing and validating digital certificates and cryptographic keys.

IT terms beginning with Q

Quality of Service (QoS):	Set of methods for prioritising traffic so that time-critical applications are transmitted reliably.
Quarter Inch Cartridge (QIC):	Refers to a magnetic tape backup system.

IT terms beginning with R

Rack Server:	Server system designed for space-efficient horizontal installation in standardised server cabinets and data centre racks.
Radio Access Network (RAN):	Part of a mobile network that connects end devices to a mobile operator's core network using wireless communication technologies.
Ransomware:	Malware that encrypts data and makes its release conditional on a payment.
Rapid Spanning Tree Protocol (RSTP):	Network protocol for preventing loops in Ethernet networks while providing rapid recovery of redundant connections following topology changes.
Read Access Memory (RAM):	Volatile working memory that holds data and programs during operation.
Received Signal Strength Indicator (RSSI):	Measurement used to assess the strength of a received radio signal, for example in wireless networks.
Recursive Resolver:	DNS server that processes name resolution requests from clients and retrieves the required DNS information from other name servers.
Redundancy:	Duplication of components so that a failure does not interrupt operations.
Redundant Array of Independent Disks (RAID):	Combination of multiple drives into an array for increased resilience or performance.
Refurbished Hardware:	Previously used IT equipment that has been inspected, reconditioned and prepared for another period of operation in a defined functional condition.
Refurbished IT:	An approach to the design, use and management of information technology throughout the entire life cycle of IT systems.
Refurbishment:	Describes the certified refurbishment of pre-owned IT hardware.
Repeater:	Network component that amplifies signals and thereby extends the range of a transmission link.
RESTCONF:	HTTP-based network management protocol for programmatically configuring and retrieving data from network devices using structured data models.
Ring Topology:	Network structure in which devices form a circular connection, with each participant directly connected to two neighbouring devices.
Rogue AP Detection:	Security function for identifying unauthorised or potentially malicious wireless access points within or near an enterprise network.
Role-Based Access Control (RBAC):	Access control model that manages user permissions based on predefined roles and their associated access rights.
Rollback Plan:	Predefined procedure for restoring a previous system state when a planned change fails or causes unexpected issues.
Root-Exploit:	Exploits vulnerabilities to gain administrator privileges.
Route Summarization:	Routing method that combines multiple contiguous IP networks into a common route to create more compact routing tables.
Router:	Network component that forwards data packets between different networks and determines their path.
Routing Protocol for Low-Power and Lossy Networks (RPL):	Controls routing in IoT networks.
Runbook:	Documented collection of standardised instructions and procedures for consistently performing recurring IT operations, maintenance and incident processes.

IT terms beginning with S

Scalability:	Describes the ability of IT systems to handle increasing demands.
Secrets Management:	Centralised management and protection of sensitive credentials such as passwords, API keys, tokens and cryptographic keys.
Secure Access Service Edge (SASE):	Cloud-based architecture that combines networking and security functions within a centrally managed platform for secure access to applications and IT resources.
Secure Shell (SSH):	Enables an encrypted network connection.
Secure Sockets Layer (SSL):	Deprecated cryptographic network protocol originally designed to encrypt and secure data transmission between clients and servers.
Security Information and Event Management (SIEM):	Centralised security solution for collecting, correlating and analysing event and log data from different IT systems to detect potential security incidents.
Security Operations (SecOps):	Organisational and technical approach to continuously monitoring, detecting, analysing and responding to security risks and cyberattacks across an IT infrastructure.
Security Orchestration, Automation, and Response (SOAR):	Centralised security platform that connects security tools and automates the processing, analysis and response to IT security incidents.
Security vulnerabilities:	Describes a vulnerability in hardware or software.
Serial Advanced Technology Attachement (SATA):	Describes an interface for storage drives.
Server:	Central system that provides services, applications and data to clients in the network.
Server Hosting:	Provision and operation of server systems within professional data centre infrastructure with network, power and internet connectivity.
Service Level Agreement (SLA):	Contractual agreement between a provider and customer that defines measurable requirements for the quality, availability and scope of an IT service.
Service Level Indicator (SLI):	Measurable metric used to evaluate the actual quality and performance of an IT service against defined criteria.
Service Level Objective (SLO):	Defined target for the measurable quality and reliability of an IT service within a specified period.
Service Mesh:	Infrastructure layer for centrally controlling, securing and monitoring communication between distributed applications and microservices.
Session Layer:	Layer of the OSI model responsible for establishing, managing and synchronising communication sessions between applications.
Signal-to-Noise Ratio (SNR):	Measurement of the relationship between desired signal strength and background noise within a network or wireless connection.
Simple Mail Transfer Protocol (SMTP):	Enables email transmission.
Simple Network Management Protokoll (SNMP):	Enables monitoring and management of network devices.
Site Reliability Engineering (SRE):	IT operations approach that combines software engineering and operations to run reliable, scalable and automated IT services.
Site Survey:	Systematic analysis of a network environment for planning, assessing and optimising Wi-Fi coverage, signal quality and access point placement.
Small Form-factor Pluggable (SFP):	Pluggable transceiver module that connects network components to fibre or copper links.
Smart Switch:	Network switch with basic management capabilities for configuring and monitoring small and medium-sized Ethernet networks.
Software as a Service (SaaS):	Provides software as a cloud service.
Software License:	Governs the use of software.
Software-defined Wide Area Network (SD-WAN):	Concept for software-based control of wide area connections through centralised policies.
Software-definiertes Netzwerk (SDN):	Network architecture for centralised and programmable control of network resources by separating the control plane from the data plane.
Solid State Drive (SSD):	Refers to a flash-based storage drive.
Spam:	Describes unsolicited electronic messages.
Spanning Tree:	Network mechanism for preventing loops in redundant Layer 2 networks by controlling which available connections actively forward traffic.
Spanning Tree Protocol (STP):	Layer 2 network protocol designed to prevent loops in Ethernet networks with redundant connections between switches.
Split DNS:	DNS configuration that returns different DNS responses and IP addresses for identical domain names depending on the requesting network or location.
SQL Injection:	Cyberattack against database-driven applications in which manipulated input is used to trigger unauthorised execution of SQL commands.
Star Topology:	Network structure in which all endpoints are connected through separate links to a central network device such as a switch.
Stateless Address Autoconfiguration (SLAAC):	IPv6 mechanism for automatically configuring IP addresses and basic network settings without central address assignment by a DHCPv6 server.
Storage Area Network (SAN):	Dedicated network that connects storage systems to servers at block level.
Storage Class Memory (SCM):	Manages digital security certificates.
Storage-Router:	Connects storage networks.
Streaming Telemetry:	Continuous transmission of current operational and performance data from network devices to central monitoring and analytics platforms.
Subnetting:	Method of dividing an IP network into smaller logical networks for structured addressing and more efficient network management.
Supernetting:	Method of combining multiple contiguous IP networks into a larger address range to create a more efficient routing structure.
Switch:	Connects devices within a network.
Switched Port Analyzer (SPAN):	Switch functionality that mirrors network traffic from selected ports or VLANs to a dedicated port for analysis and monitoring.
Switching Module:	Modular network component used to expand switches and other network devices with additional ports, interfaces or switching capacity.
Syslog:	Standardised method for transmitting and centrally collecting event, status and error messages from network devices and IT systems.

IT terms beginning with T

Telecommunications:	Covers the transmission of information over distance.
Terraform:	Open-source tool for automatically provisioning and managing cloud, network and IT infrastructure through declarative configuration files.
Third-Party Maintenance (TPM):	Maintenance and support model for IT hardware provided by an independent service provider rather than the original manufacturer.
Threat Intelligence:	Processed information about current and potential cyber threats used to detect, assess and defend against attacks on IT systems.
Total Cost of Ownership (TCO):	Calculation of all direct and indirect costs associated with an IT system or investment throughout its entire period of use.
Tower Server:	Server system in a standalone enclosure similar to a desktop computer that does not require dedicated rack infrastructure.
Transceiver:	Transmits and receives network signals.
Transit:	Forwarding of data traffic through an external provider's network to reach other networks and destinations across the internet.
Transmission Control Protocol / Internet Protocol (TCP/IP):	Describes the foundation of Internet communication.
Transport Layer:	Fourth layer of the OSI model responsible for end-to-end data transmission between applications running on different network devices.
Transport Layer Security (TLS):	Cryptographic network protocol for encrypted and authenticated data transmission between applications and IT systems.
Tree topology:	Hierarchical network structure in which multiple star-shaped network segments are connected through higher-level nodes.
Twisted Pair Cable:	Network cable with pairs of twisted copper conductors for transmitting electrical data and communication signals in Ethernet networks.

IT terms beginning with U

Ultra-Wide Band (UWB):	Short-range wireless technology for high-speed data transmission and precise positioning and distance measurement between compatible devices.
Underlay:	Physical or logical network infrastructure that provides fundamental IP connectivity and serves as the transport layer for virtual networks built on top of it.
Undervoltage:	Electrical voltage below the intended operating range that can affect the stable operation of electronic equipment and IT systems.
Unicast:	Transmits data to a single recipient.
Unified Networking:	Network architecture for managing and transporting different data, storage and communication services across an integrated infrastructure.
Uninterruptible Power Supply (UPS):	System that continues to power connected equipment during outages and protects against supply faults.
Unique Local Addresses (ULA):	Private IPv6 addresses for internal communication within local networks that are not intended to be routed across the public internet.
Unmanaged:	Describes network devices without centralized management.
Unmanaged Switch:	Network switch without configurable management functions that automatically connects Ethernet devices within a local network.
UPS Racks:	Rack-based systems for housing and integrating uninterruptible power supplies and associated components in server and data centre environments.
User Datagram Protocol (UDP):	Enables connectionless data transmission.

IT terms beginning with V

Virtual Extensible LAN (VXLAN):	Overlay technology for extending Layer 2 networks across an existing Layer 3 infrastructure and providing scalable virtual network segmentation.
Virtual Local Area Network (VLAN):	Logical segmentation of a physical network into separate broadcast domains for structured organisation and control of network traffic.
Virtual Private LAN Service (VPLS):	Layer 2 VPN technology that connects geographically separated locations across a provider network so they can communicate as a common Ethernet LAN.
Virtual Private Network (VPN):	Enables an encrypted network connection over the Internet.
Virtual Router Redundancy Protocol (VRRP):	Protocol that combines multiple routers into a resilient virtual default gateway.
Virtual Routing and Forwarding (VRF):	Network technology that enables multiple isolated routing tables to operate independently on the same router or Layer 3 switch.
Virtual server:	Provides a software-based server.
Virus:	Describes self-replicating malicious software.
Voice over IP (VoIP):	Method for transmitting voice over IP networks instead of traditional telephone lines.
VPS Hosting:	Hosting model that provides virtualised server resources with an independent system environment on shared physical server infrastructure.
vSwitch:	Software-based network switch for connecting and controlling traffic between virtual machines and physical networks.
Vulnerability Management:	Continuous process for identifying, assessing, prioritising and remediating security vulnerabilities across IT systems, applications and networks.

IT terms beginning with W

Web Application Control:	Controls access to web applications.
Web Application Firewall (WAF):	Security solution for monitoring and filtering HTTP and HTTPS traffic between web applications and their users.
Web Server:	Server system that provides websites, web applications and other web-based content through network protocols such as HTTP and HTTPS.
Whaling:	Targeted form of phishing aimed at senior executives and other individuals with extensive access rights or decision-making authority.
Wide Area Network (WAN):	Refers to a wide area network.
Wireless Local Area Network (WLAN):	Enables wireless network communication.
WLAN Roaming:	Automatic transition of a wireless client between different access points within the same wireless network while maintaining connectivity where possible.
WPA2-Enterprise:	Wi-Fi security method with centralised user or device authentication for controlled access to enterprise wireless networks.
WPA3-Enterprise:	Wi-Fi security method for enterprise networks with centralised authentication and enhanced cryptographic protection for wireless connections.

IT terms beginning with X

XFP:	Refers to a transceiver for 10 Gigabit Ethernet.

IT terms beginning with Y

YANG Models:	Standardised data models for structurally defining configuration, operational state and management functions of network devices and services.

IT terms beginning with Z

Z-Wave:	Wireless technology for networking and control of compatible devices in smart home and building automation systems.
Zero Day Exploit:	Exploits an unknown security vulnerability.
Zero Touch Provisioning (ZTP):	Automated method for initially configuring and deploying network devices without requiring manual setup directly on the device.
Zero Trust:	IT security concept based on continuously verifying users, devices and access requests regardless of their location inside or outside the corporate network.
Zero-Day Vulnerability:	Newly discovered vulnerability in software, hardware or firmware for which an appropriate security patch is not yet available when it becomes known.
ZigBee:	Wireless technology for short-range communication between connected devices.
Zone Transfer:	DNS mechanism for transferring zone data between authoritative DNS servers to synchronise domain information.