Interconnecting dissimilar LANs: in a building with both Ethernet and Token Ring networks, which device enables communication between the different LAN architectures and protocols?

Introduction / Context: Mixed environments may include LANs with different media access methods and frame formats (e.g., Ethernet vs. Token Ring). To share resources across these systems, you may need a device that can translate or interoperate across different protocols/architectures—not merely forward frames unchanged.

Given Data / Assumptions:

• Ethernet and Token Ring differ at Layer 2 (frame formats, media access).
• Some scenarios require protocol translation, name service mediation, or application-layer adaptation.
• Goal: enable communications between dissimilar LANs, not just extend the same LAN type.

Concept / Approach: A gateway performs protocol conversion and higher-layer mediation so endpoints on different LAN architectures can interoperate. In contrast, a bridge forwards frames within the same Layer 2 protocol family; a router forwards at Layer 3 but does not translate between incompatible Layer 2 protocols by itself; a repeater operates at Layer 1 and cannot resolve protocol differences. Therefore, the correct choice for “dissimilar LANs using different protocols” is a gateway.

Step-by-Step Solution:

Verification / Alternative check: Historical solutions included multi-protocol gateways and application gateways to integrate Ethernet and Token Ring segments for file/print services.

Why Other Options Are Wrong:

Common Pitfalls: Assuming routers solve all interconnection problems; routers do not convert frame formats or application protocols.

Final Answer: Gateway.