Technical Glossary

A

API Gateway: Centralised entry point for API requests handling authentication, rate limiting, request transformation, and routing to backend services.

Autonomous System (AS): Collection of IP networks under single administrative control sharing common routing policy. Identified by unique AS number (ASN) in BGP routing.

B

BGP (Border Gateway Protocol): Path vector routing protocol managing inter-autonomous system routing. Exchanges network reachability information between networks.

Blue-Green Deployment: Release strategy maintaining two identical production environments. Traffic switches between environments for zero-downtime deployments.

C

Circuit Breaker: Design pattern preventing cascading failures by stopping requests to failing dependencies after threshold exceeded.

Container: Lightweight, standalone executable package containing application code, runtime, libraries, and dependencies. Provides consistent execution environment.

CQRS (Command Query Responsibility Segregation): Pattern separating read and write operations into different models, optimising each for specific use case.

D

DWDM (Dense Wavelength Division Multiplexing): Optical technology transmitting multiple channels over single fibre using different light wavelengths.

Disaster Recovery (DR): Processes and procedures for recovering infrastructure and data following major incident or catastrophic failure.

E

Event-Driven Architecture: Design pattern where components communicate through production, detection, and consumption of events.

Eventual Consistency: Consistency model where system guarantees data convergence to consistent state eventually, without immediate synchronisation.

F

Failover: Automatic switching to redundant system component when primary fails, maintaining service availability.

Fibre Optic Cable: Physical medium transmitting data as light pulses through glass or plastic fibres, enabling high-bandwidth long-distance communication.

G

GitOps: Operational framework using Git repositories as single source of truth for declarative infrastructure and applications.

H

Horizontal Scaling: Increasing capacity by adding more instances of components, distributing load across multiple units.

I

Infrastructure as Code (IaC): Managing and provisioning infrastructure through machine-readable definition files rather than manual processes.

Internet Exchange Point (IXP): Physical infrastructure enabling networks to interconnect and exchange traffic directly, reducing transit costs and latency.

K

Kubernetes: Open-source container orchestration platform automating deployment, scaling, and management of containerised applications.

L

Load Balancer: Device or software distributing network traffic across multiple servers, preventing overload and improving availability.

M

Microservices: Architectural style structuring application as collection of loosely coupled, independently deployable services.

MPLS (Multi-Protocol Label Switching): Routing technique forwarding packets based on labels rather than network addresses, enabling traffic engineering and VPNs.

MTTR (Mean Time To Repair): Average time required to repair failed component and restore service.

O

Observability: Ability to understand internal system state through external outputs including metrics, logs, and traces.

OSPF (Open Shortest Path First): Link-state interior gateway protocol using Dijkstra algorithm for optimal path calculation within autonomous systems.

R

Redundancy: Duplication of critical system components to maintain functionality during component failures.

RPO (Recovery Point Objective): Maximum acceptable data loss measured in time. Determines backup frequency requirements.

RTO (Recovery Time Objective): Maximum acceptable downtime following disaster. Influences recovery strategy selection.

S

Service Mesh: Infrastructure layer handling service-to-service communication, providing observability, security, and traffic management without application code changes.

Sharding: Database architecture pattern horizontally partitioning data across multiple servers based on shard key.

SDN (Software-Defined Networking): Approach separating network control plane from data plane, enabling programmable network management.

V

Vertical Scaling: Increasing capacity by adding resources (CPU, memory) to existing instances rather than adding more instances.

VPN (Virtual Private Network): Encrypted connection over public network creating secure extension of private network.