Difficulty: Easy
Correct Answer: Router
Explanation:
Introduction / Context:Interconnecting distinct LANs across sites requires a device that forwards traffic at the network layer and can select paths between different IP subnets. This is a classic use case for routing rather than simple Layer-2 extension.
Given Data / Assumptions:
Concept / Approach:
Routers operate at OSI Layer 3, maintain routes, and forward packets between networks with different subnets. They can establish site-to-site VPNs or use dedicated WAN links. Hubs and simple cables do not provide Layer-3 forwarding. Bridges connect Layer-2 segments within the same broadcast domain and are not ideal for routed, multi-site internetworking.
Step-by-Step Solution:
Step 1: Identify that traffic must cross IP subnet boundaries between sites.Step 2: Select a Layer-3 device capable of path selection and inter-subnet forwarding.Step 3: Choose router as the appropriate device.Step 4: Note that modern implementations may use firewalls or SD-WAN appliances that include routing functions.Verification / Alternative check:
Enterprise networks universally route between sites using routers or routing-capable security appliances. This validates the choice.
Why Other Options Are Wrong:
Modem: Provides line signaling for WAN access but not full inter-LAN routing by itself.
Cable: A medium, not a routing device.
Hub: Layer-1 repeater; no IP forwarding.
Bridge: Layer-2 only; unsuitable for scalable multi-site interconnection.
Common Pitfalls:
Assuming any interconnect device suffices. Multi-site communication requires Layer-3 routing and often security policies, which routers provide.
Final Answer:
Router
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