multiarea

Multiarea is a term used to describe systems that are divided into multiple areas, regions, or administrative domains to improve scalability, manageability, or policy enforcement. In information technology and networking, multiarea designs segment a large network into smaller, logically defined areas. Each area contains its own routing information and topology, while inter-area communication is controlled at defined boundaries. This enables networks to scale without flooding every router with the entire routing database.

When using a routing protocol such as OSPF or IS-IS, multiarea configurations rely on special border routers to connect areas. In OSPF, an area border router (ABR) connects one or more areas to the backbone area (area 0). Each area maintains its own link-state database; inter-area routes are summarized and carried across area borders by summary LSAs or equivalent mechanisms. This design reduces routing overhead and confines instability to individual areas, improving convergence in large networks. Backbone continuity, virtual links, and careful area design are important considerations in multiarea OSPF deployments.

Outside of routing, multiarea concepts appear in other domains, including distributed systems, data center design, and urban planning, where operations are distributed across multiple geographic or administrative regions. In such contexts, multiarea architectures support policy enforcement, localization of control, and resilience through decentralization, but they also introduce coordination and compliance challenges across areas.

Overall, multiarea describes an approach to organizing complex systems by partitioning them into smaller areas connected through defined boundaries, balancing scalability, performance, and manageability.