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> Routing Protocols
> OSPF's Metric: Cost
OSPF chooses the least-cost route between the router and a subnet by adding up the outgoing interfaces' OSPF costs. Each interface has an OSPF cost associated with it. The router looks at each possible route, adds up the costs on the interfaces out which packets would be forwarded on that route, and then picks the least-cost route.
Odom, Wendell (2008) CCNA ICND2 Official Exam Certification Guide, Second Edition. Indianapolis: Cisco Press.