Root: WRM Database > Information Technology > Certifications > CCNA > Routing Protocols > OSPF > LSDB (Link State Database; or OSPF Topology Table; or OSPF Database) > Using the Dijkstra SPF Algorithm
Root: WRM Database > Information Technology > Certifications > CCNA > Routing Protocols > OSPF > Dijkstra SPF Algorithm > Using the Dijkstra SPF Algorithm
Root: WRM Database > Information Technology > Certifications > CCNA > Routing Protocols > OSPF > Link LSA > Using the Dijkstra SPF Algorithm
Root: WRM Database > Information Technology > Certifications > CCNA > Routing Protocols > OSPF > Router LSA > Using the Dijkstra SPF Algorithm



Using the Dijkstra SPF Algorithm


The OSPF topology database consists of lists of subnet numbers (called links, hence the name link-state database). It also contains lists of routers, along with the links (subnets) to which each router is connected. Armed with the knowledge of links and routers, a router can run the SPF algorithm to compute the best routes to all the subnets. The detailed information in each LSA - things such as a link LSA listing the routers attached to the subnet, and a router LSA listing its IP addresses and masks - gives the SPF algorithm enough information to figure out which routers connect to each subnet and create the mathematical equivalent of a network diagram.







References

Odom, Wendell (2008) CCNA ICND2 Official Exam Certification Guide, Second Edition. Indianapolis: Cisco Press.