Which scenario typically requires a gateway?

A gateway serves as a crucial point in a network, especially when different network protocols or architectures need to communicate. In the scenario where an IP network needs to connect to an Apple Talk network, a gateway is essential because these two networks operate using different protocols. The gateway translates the communication between them, allowing devices on the IP network to communicate seamlessly with devices on the Apple Talk network.

This function of protocol translation is what differentiates a gateway from other networking devices like routers or switches, which generally deal with similar protocols or simply forward packets without modification. In scenarios involving devices that operate on different networking standards, such as the one involving IP and Apple Talk, a gateway's capability to adapt and translate is critical for successful communication and data transmission between the two disparate networks.

In contrast, connecting a LAN to a WAN, connecting computers in the same LAN, or connecting two routers typically involves devices like routers or switches that don't require extensive protocol translation. Therefore, the scenario pertaining to the connection between an IP network and an Apple Talk network distinctly highlights the role of a gateway.