OSPF Routing Protocol: Explained | CCNA Exam Prep

OSPF Routing Protocol

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Which statements describe the routing protocol OSPF? (Choose three.)



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A. B. C. D. E. F.


OSPF (Open Shortest Path First) is a link-state routing protocol that operates within a single autonomous system (AS). Here are the three statements that correctly describe OSPF:

A. It supports VLSM: OSPF is a classless routing protocol that supports variable-length subnet masking (VLSM). This allows for more efficient use of IP address space by allowing different-sized subnets to be used within a network.

C. It confines network instability to one area of the network: OSPF uses areas to divide the network into smaller, more manageable pieces. Each area has its own topology database, and routers in different areas only exchange routing information with routers in their own area. This limits the scope of network instability to a single area, reducing the impact of network changes or failures on the rest of the network.

E. It allows extensive control of routing updates: OSPF provides a number of features that allow network administrators to control the flow of routing information. For example, OSPF supports route summarization, which can reduce the size of routing tables and decrease routing overhead. OSPF also allows for the use of access control lists (ACLs) to filter routing updates based on source, destination, or other criteria.

Here are the statements that do not correctly describe OSPF:

B. It is used to route between autonomous systems: OSPF is an intra-domain routing protocol that is used to route within a single autonomous system (AS). To route between autonomous systems, an inter-domain routing protocol like BGP (Border Gateway Protocol) is typically used.

D. It increases routing overhead on the network: OSPF does require more initial configuration and overhead than simpler routing protocols like RIP (Routing Information Protocol), but it is generally considered to be more efficient and scalable for larger networks.

F. It is simpler to configure than RIP v2: OSPF is generally more complex to configure than RIP, especially in larger networks with multiple areas. RIP v2 does not support VLSM or route summarization, however, so it may be less flexible in certain situations.