At which point in a one-way, multiple hop, end-to-end IP communications session will a frame have to be built?

In a one-way, multiple hop, end-to-end IP communications session, a frame needs to be constructed at the outbound port of each hop's router. This is because, at each hop, the data packet must be encapsulated into a frame suitable for the specific link layer technology that connects the router to the next network segment.

When data is transmitted across networks, it is sent in packets at the network layer (IP layer), but to move those packets over physical mediums, they must be framed. Each router examines the incoming packet, processes it (which can include routing decisions), and then builds a new frame to send it out on the respective outbound link, which may involve adjusting for things like the frame format, address encapsulation, and error checking.

Considering the options provided: while the sending host's LAN port is responsible for building the initial frame for transmission, this question specifically focuses on the scenario involving multiple hops. The receiving host won't build a frame until it's processing the final arrival, but that doesn't apply to the hops in between. The sender's gateway performs routing but does not need to build a new frame unless it is the first router in the path. Thus, the crucial framing activity occurs at each hop's router as they pass the