OSPF stands for Open Shortest Path First, which is a link-state routing protocol that is hierarchal by nature and uses the router ID to control convergence. OSPF divides a large network into areas, which are logical groupings of routers that share the same topology information. Each area has a unique identifier and a designated router that connects it to the backbone area (area 0). OSPF uses the router ID, which is a 32-bit number that uniquely identifies each router in the network, to establish adjacencies and exchange routing information. OSPF also uses the router ID to break ties when choosing the best path to a destination. OSPF converges faster than distance-vector routing protocols such as RIP and EIGRP, as it uses the Dijkstra algorithm to calculate the shortest path based on the link cost. BGP, on the other hand, is a path-vector routing protocol that is used to exchange routing information between autonomous systems on the Internet. BGP does not use the router ID to control convergence, but rather uses attributes such as AS path, local preference, and MED to select the best route. BGP is not hierarchal by nature, as it does not divide the network into areas, but rather uses prefixes and policies to control the routing behavior.
References
* 1: OSPF - N10-008 CompTIA Network+ : 2.1
* 2: CompTIA Network+ N10-008 Certification Study Guide, page 146-149
* 3: CompTIA Network+ N10-008 Exam Subnetting Quiz, question 19
* 4: CompTIA Network+ N10-008 Certification Practice Test, question 8

A cable tester is a tool that can verify the integrity and functionality of a network cable. It can measure the electrical characteristics of the cable, such as resistance, capacitance, and impedance, and detect any faults or defects, such as shorts, opens, or crosstalk. A cable tester can help the network administrator troubleshoot the problem by determining if the cable is faulty or not. A tone generator is a tool that can send an audible signal through a cable to help locate and identify it. A multimeter is a tool that can measure voltage, current, and resistance of electrical circuits. An optical time-domain reflectometer (OTDR) is a tool that can test the quality and length of fiber optic cables.