What is required for Strict Source Routing?

• A. At least two routers must be designated
• B. The route cannot be predetermined
• C. Routers along the path are discovered automatically
• D. All routers along the route must be designated in the IP options

Answer: (D)

Strict Source Routing requires the sender to specify the entire path the packet must take, listing every router along the route in the IP options. The packet is then forwarded from the current router to the next one exactly as listed, with no deviations. Because the path is fixed by the source, every router along that route must be designated in the IP options. The other ideas don’t fit: the route isn’t defined by just two routers, it isn’t allowed to deviate from a predetermined path, and the path isn’t discovered automatically—the sender defines it explicitly.