Definition
An area border router is a networking device that connects open shortest path first (OSPF) areas to the core network (“0” or “0.0.0.0”).
It is placed at the border of OSPF areas to act as information entry and exit points. Border Area Routers maintain routing information on both OSPF areas and the backbone network to ensure they communicate smoothly.
Other Routers in OSPF
- Autonomous system boundary routers (ASBR): They use multiple routing protocols to route information received from external autonomous systems to internal ones.
- Internal routers: They route information within the same network, and all their interfaces are in a single OSPF area.
- Backbone routers (BR): They have at least one interface in the backbone network.
Area Border Routers Benefits
- Streams communication and enhances efficiency: Complex networks are divided into segments controlled by border area routers to ease congestion and improve performance.
- Maintaining and sharing routing information: ABRs maintain routing information of both OSPF areas and backbone networks. They share this information with other routers to help them make more informed decisions and optimize their routing tables.
Area Border Router Examples
- Data centre interconnects: Modern data centres use physical or virtual redundant networks to maintain high availability. They use ABRs to route and control traffic in each virtual or physical OSPF area.
- Enterprise networks: Large organizations with multiple branches have multiple OSPF areas to manage network resources efficiently. They use ABRs to connect all the OSPF areas to the core network.
- Internet service providers (ISPs): ISPS divide their networks into multiple OSPF areas and use ABRs to route information between them and the backbone network.