In a network with two Internet service providers and several routers, there is a single point of failure. Which router must stay online to maintain an Internet connection?

In a network with two Internet service providers and several routers, there is a single point of failure. Which router must stay online to maintain an Internet connection?

• A. Router B
• B. Router A
• C. Router C
• D. Router D

Answer: (B)

The thing being tested is the device that serves as the gateway to the Internet. If the gateway router that connects your internal network to the outside world goes down, there’s no path to either Internet Service Provider, and Internet access is lost no matter what else is running inside. In this setup, Router A is the edge router that interfaces with both ISPs. Keeping Router A online keeps at least one path to the Internet open. The other routers handle traffic inside the network, so their failure would disrupt internal communication but wouldn’t by itself eliminate Internet access as long as the gateway remains up. Therefore, Router A must stay online to maintain an Internet connection.

The thing being tested is the device that serves as the gateway to the Internet. If the gateway router that connects your internal network to the outside world goes down, there’s no path to either Internet Service Provider, and Internet access is lost no matter what else is running inside.

In this setup, Router A is the edge router that interfaces with both ISPs. Keeping Router A online keeps at least one path to the Internet open. The other routers handle traffic inside the network, so their failure would disrupt internal communication but wouldn’t by itself eliminate Internet access as long as the gateway remains up. Therefore, Router A must stay online to maintain an Internet connection.