Which of the following statements is not true with regard to routers?
A. They forward broadcasts by default.
B. They can filter the network based on Network layer information.
C. They perform path selection.
D. They perform packet switching.
A is an example of a device that operates only at the physical layer.
A. Hub
B. Switch
C. Router
D. Bridge
The Correct Answer and Explanation is :
Let’s analyze each of the statements to determine which one is not true with regard to routers:
A. They forward broadcasts by default.
This statement is not true. Routers do not forward broadcasts by default. They are designed to operate at the Network Layer (Layer 3) of the OSI model, and one of their key functions is to determine the best path for data packets to travel across different networks. Routers generally do not forward broadcast traffic, as broadcast packets are typically intended for all devices within the same subnet. A router will only forward broadcast packets if specifically configured with certain settings (such as with multicast routing or if a broadcast needs to cross subnets via certain routing protocols).
B. They can filter the network based on Network layer information.
This statement is true. Routers operate at Layer 3 of the OSI model, which is the Network Layer. This allows them to filter network traffic based on IP addresses (Network Layer information). For example, routers can filter traffic using access control lists (ACLs), allowing or denying traffic based on the destination or source IP address.
C. They perform path selection.
This statement is true. Routers are responsible for path selection in the network. They use routing protocols such as OSPF, EIGRP, or BGP to determine the best path for forwarding packets across different networks. Path selection ensures that data packets follow the most efficient route based on factors like network topology, distance, or cost.
D. They perform packet switching.
This statement is true. Routers also perform packet switching. When a router receives a packet, it examines the destination IP address, checks its routing table, and forwards the packet toward the appropriate network. Packet switching ensures that data is efficiently transmitted across the network.
Correct Answer:
A. They forward broadcasts by default.
This statement is not true, as routers do not forward broadcasts by default.
Now, let’s analyze the second part of the question:
“A is an example of a device that operates only at the physical layer.”
The options are:
- A. Hub
- B. Switch
- C. Router
- D. Bridge
The correct answer is A. Hub.
Explanation:
- A. Hub: A hub is a Layer 1 (Physical Layer) device. It does not examine the data or make decisions based on network addresses. It simply forwards data received on one port to all other ports, which makes it a basic device functioning purely at the physical layer. It doesn’t have any intelligence regarding IP addresses or MAC addresses, and it doesn’t filter or segment traffic.
- B. Switch: A switch operates at Layer 2 (Data Link Layer), though some advanced switches also operate at Layer 3 (Network Layer) for routing purposes. A basic switch forwards data based on MAC addresses (Layer 2 information).
- C. Router: A router operates at the Network Layer (Layer 3), and it performs path selection and routing of data based on IP addresses.
- D. Bridge: A bridge operates at Layer 2 and is used to connect two or more network segments, filtering traffic based on MAC addresses. It can reduce collisions by segmenting networks but does not function purely at the physical layer.
Correct Answer:
A. Hub