Step 1: Understanding the Question:
The question asks to identify which of the listed network devices (Hub, Gateway, Router, Repeater) process and use IP addresses (Layer 3 of the OSI model) for packet routing and communication.
Step 2: Key Concepts of OSI Layer Devices:
- Physical Layer (Layer 1): Deals with raw bit transmission over physical media. Devices working here (like Hubs and Repeaters) have no concept of addressing (MAC or IP). They only regenerate and replicate electrical/optical signals.
- Network Layer (Layer 3): Manages host addressing and logical packet routing. Devices here (like Routers) read and use IP addresses.
- Higher Layers (Layers 4 to 7): Gateways operate at multiple layers, including the network layer and above, to connect networks using different protocols. They parse IP headers to perform protocol translation and address translation.
Step 3: Detailed Explanation:
Let us analyze each device:
- A. Hub: A Layer 1 physical device. It simply broadcasts incoming electrical signals to all ports. It cannot read IP addresses.
- D. Repeater: A Layer 1 physical device. It only amplifies or regenerates weak incoming signals. It does not look at packet data or IP addresses.
- C. Router: A Layer 3 device that connects different IP networks. It reads the source and destination IP addresses in packet headers to determine the best path to forward the packets. It uses IP addresses directly.
- B. Gateway: A protocol translation device that operates across Layer 3 and above. It uses IP addresses to coordinate data conversion and routing between incompatible networks.
- Therefore, only B (Gateway) and C (Router) use IP addresses as a means of communication.
Step 4: Final Answer:
The devices that use IP addresses for communication are B (Gateway) and C (Router).
Hence, option (B) is the correct choice.