In local area networking, which device forwards frames from one LAN segment to another LAN segment at the data link layer, enabling inter-LAN frame transmission?

Introduction / Context:
LANs are often divided into segments for performance or topology reasons. To interconnect segments while still operating at the data link layer, specific devices forward frames based on MAC addresses. This question distinguishes among common devices used in LANs and WANs.

Given Data / Assumptions:

• OSI layer focus: data link layer (Layer 2).
• Goal: transmit Ethernet frames between LAN segments.
• MAC address learning and filtering are relevant.

Concept / Approach:

A bridge is a Layer-2 device that learns MAC addresses, filters traffic, and forwards frames between LAN segments. Modern Ethernet switches are multiport bridges that perform the same fundamental function. Routers operate at Layer 3 and forward packets based on IP addresses, not raw frames across broadcast domains. Repeaters regenerate signals without MAC-level forwarding logic. Modems and gateways target different layers and functions.

Step-by-Step Solution:

Verification / Alternative check:

Switches, effectively multiport bridges, routinely interconnect VLANs or segments at Layer 2, confirming the role.

Why Other Options Are Wrong:

Router: Packet forwarding across networks, not raw frame bridging between segments.

Repeater: Bit-level regeneration only; no MAC learning.

Modem: Modulation/demodulation for WAN lines, not LAN bridging.

Gateway: Protocol conversion at higher layers; not strictly Layer 2 frame forwarding.

Common Pitfalls:

Equating any interconnection with routing. The mention of frames signals Layer 2 and therefore bridging or switching.

Final Answer:

Bridge