What similarities do OSPF and IS-IS share?

Both OSPF (Open Shortest Path First) and IS-IS (Intermediate System to Intermediate System) utilize the Shortest Path First (SPF) algorithm for route calculation. This algorithm enables both protocols to create a tree structure to determine the most efficient path for data to travel across a network. As routers exchange information about the network's topology, they can update their view of the network and rerun the SPF algorithm as necessary to ensure optimal routing paths.

This similarity is fundamental in link-state routing protocols, as both OSPF and IS-IS gather information from their neighboring routers to build a comprehensive understanding of the network. The use of the SPF algorithm helps ensure that traffic is routed efficiently and effectively based on the latest network topology information.

The other choices do not accurately reflect the characteristics shared by OSPF and IS-IS. While both protocols do build views of network topology, they do not build merely partial views; they create a complete representation of the network. They also provide robust capabilities for scaling and handle large networks effectively; thus, the statement about scaling is not accurate in regard to either protocol.