What does OSPF stand for?
OSPF stands for Open Shortest Path First. A link-state interior routing protocol: every router builds a complete map of its area and runs Dijkstra's algorithm to find the lowest-cost path, with cost based on bandwidth. It converges faster than RIP and scales through areas, with area 0 as the backbone.
OSPF is a routing protocol for use inside one organization's network. Every router learns the state of all links in its area, builds the same map and calculates the shortest path to each destination, where the cost of a link normally reflects its bandwidth. When a link fails, routers flood the change and recalculate within seconds. Large networks are divided into areas to keep the map small, and every area connects to the backbone, area 0.
OSPF in practice: an example
A campus has two paths between buildings: a 10 gigabit fibre and a 1 gigabit backup. OSPF gives the fibre the lower cost, so traffic uses it. When the fibre is cut during building work, the routers detect the lost neighbour, recalculate, and traffic moves to the backup link in a few seconds.
What OSPF is confused with
OSPF vs BGP: what is the difference?
OSPF picks the lowest-cost path inside one network. BGP connects different networks to each other and chooses by policy. What BGP stands for
OSPF vs RIP: what is the difference?
RIP is a distance-vector protocol that counts hops, with a limit of 15, and converges slowly. OSPF is a link-state protocol that uses link cost and converges quickly.
Which exams cover OSPF?
OSPF is on the official CompTIA acronym list for one of the four exams covered here.
- Network+ N10-009: 2.0 (Network Implementation).
Each number is a CompTIA exam objective and the name in brackets is its domain. The exam puts the term in a scenario; it does not ask you to recite the expansion.
Check yourself: two practice questions
Written by CertSprint for this page. They are not taken from any exam.
1. Which value does OSPF use to choose the best path?
- Hop count only
- Link cost, normally based on bandwidth
- The age of the router
- The alphabetical order of interface names
Show the answer
B. Link cost, normally based on bandwidth. OSPF adds up the cost of the links on each path and takes the lowest total. Hop count is what RIP uses.
2. In a multi-area OSPF design, which area must all other areas connect to?
- Area 0
- Area 1
- The highest-numbered area
- No area; areas are independent
Show the answer
A. Area 0. Area 0 is the backbone. Routing information between areas passes through it.
Sources: RFC 2328: OSPF Version 2. The acronym and its expansion come from CompTIA's official acronym lists, linked from each exam glossary above. The explanation, example and questions are CertSprint's own, checked against these sources on 11 November 2026.