WAN Topologies

Correct Answer: Metro Ethernet

The Metro Ethernet would be the best WAN topology in this case because it reduces latency and provides a cost-effective and scalable way to connect two office buildings. It doesn't require a dedicated leased line, which fits the stated requirements. On the other hand, Point-to-Point involves a dedicated circuit between two points which contradicts the initial requirement. Both Frame Relay and ATM are technologies that once served as popular choices for network backbone systems, but they have been largely replaced by more modern technologies.

Correct Answer: MPLS

The best choice of WAN topology for a company expanding its operations that requires scalability, redundancy, and easy integration with new sites is MPLS (Multiprotocol Label Switching). MPLS is a versatile, scalable, and efficient network solution. Being protocol-agnostic, it supports almost any kind of transport medium, making it highly suitable for integrating new sites into the network. Moreover, MPLS provides redundancy, ensuring that there's no single point of failure, which makes it a highly reliable solution for enterprise networks. ISDN (Integrated Services Digital Network) is outdated and lacks scalability. Point-to-Point topology is not the best choice because it doesn't offer inherent redundancy and can become complex and costly for larger networks. Circuit Switching is not suitable because it's inefficient and doesn't provide the best redundancy or scalability. These qualities make it unsuitable for a robust, growing business network.

Correct Answer: Metro Ethernet

Metro Ethernet is the best choice in this scenario for a few reasons. First, it is designed to handle large amounts of data, which fits well with the university's requirement. Second, Metro Ethernet can span a city-wide area, making it a good fit for interconnecting campuses across the city. Lastly, it's a cost-effective solution, providing high-speed connectivity at an economical price. On the other hand, the alternatives like Point-to-Multipoint, MPLS, and Frame Relay might not be as cost-effective or efficient in handling large amounts of data over a broad area, especially within the context of a city-wide university campus interconnectivity.