Wide Area Networks (WAN)

Correct Answer: SD-WAN (Software-Defined Wide Area Network)

SD-WAN (Software-Defined Wide Area Network) is the correct answer because this technology allows businesses to utilize multiple providers simultaneously. It intelligently directs traffic across the wide area network, which maximizes performance and reduces potentially costly downtime. SD-WAN can be programmed to automatically switch to alternate connections if the primary connection fails, providing network redundancy and ensuring business continuity. The other options, Frame Relay, ATM (Asynchronous Transfer Mode), and Point-to-Point Protocol (PPP), do not inherently support the multiple simultaneous provider model and thus cannot provide the same level of network redundancy as SD-WAN.

Correct Answer: WAN Optimization

The best way to improve file transfer speeds without upgrading the WAN link would be through WAN Optimization. This technology uses techniques like data deduplication, compression, latency optimization and caching to speed up data transfers over wide area networks (WANs). These techniques reduce the amount of data that needs to be sent across the link, thus effectively increasing speed. Other solutions like VPLS, MPLS, and SD-WAN also play a role in network optimization, but not specifically for accelerating file transfers without changing the existing link. VPLS (Virtual Private LAN Service) and MPLS (Multi-Protocol Label Switching) can indeed improve performance in a WAN setting, but often require changes to the network architecture. SD-WAN (Software-Defined WAN) is a technology that can improve WAN efficiency and reduce costs, but it's more about intelligent path selection and network resilience, not primarily about increasing file transfer speeds.

Correct Answer: Interface congestion

The most likely cause of intermittent packet loss during periods of high usage is Interface congestion. This means that the traffic exceeds the capacity of the interface, resulting in some packets being dropped. In contrast, MTU mismatch would cause consistent packet loss, not just during high usage. Wrong cable type could cause connectivity problems, but not necessarily intermittent packet loss only at high usage times. A power outage would cause a complete loss of connectivity, not just packet loss during high usage times.