# OSPF extension for the support of multi-area networks with arbitrary topologies

## TL;DR

This paper proposes an extension to OSPF that enables multi-area networks with arbitrary topologies using a link state approach, overcoming existing limitations of hierarchy and optimality in inter-area routing.

## Contribution

An OSPF extension adopting link state inter-area routing to support arbitrary topologies and improve routing optimality, applicable to both IPv4 and IPv6 versions.

## Key findings

- Supports multi-area networks with arbitrary topologies
- Overcomes two-level hierarchy limitation
- Potentially impacts Internet routing operations

## Abstract

OSPF currently supports multi-area networking with two severe limitations, due to the distance vector approach taken in the inter-area routing protocol: (i) the multi-area topology is restricted to a two-level hierarchy, and (ii) globally optimal routing may not be achieved. In this letter, we propose an OSPF extension that overcomes these limitations by adopting a link state inter-area routing protocol. The extension applies to both OSPFv2 (IPv4) and OSPFv3 (IPv6), and is fully transparent to area-internal routers. Despite its simplicity, this extension may have a large impact in the operation of the current Internet.

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Source: https://tomesphere.com/paper/1704.08916