Local area networks and ARCNET hubs: which statement is correct regarding realistic characteristics (expansion limits, access costs, and hub behavior) for these technologies?

Introduction / Context:
LAN technologies come with practical limits on size, topology, and signaling. ARCNET (Attached Resource Computer NETwork), one of the earliest LANs, supported star-wired bus topologies using hubs with specific signal-handling behavior. This question asks you to identify the realistic and historically accurate statement among several distractors about LANs and ARCNET hubs.

Given Data / Assumptions:

• ARCNET used token passing and supported star-wired and bus variants with active hubs.
• Hubs in ARCNET implemented signal conditioning/steering rather than layer-3 routing.
• General statements about LANs should reflect realistic limits and economics.

Concept / Approach:
Evaluate each option for historical and technical accuracy: (a) “alternative routing” describes network-layer path selection, not hub behavior in ARCNET. (b) “unlimited expansion” is false; LANs have physical, address, and timing limits. (c) “low-cost access for low-bandwidth channels” is vague/misleading for LANs whose goals are typically low latency and relatively high bandwidth locally. (d) ARCNET hubs used directionalized transmission/retiming to steer and regenerate frames toward appropriate segments in star-wired bus deployments—this aligns with documented behavior of ARCNET active hubs. Therefore, (d) is the correct statement.

Step-by-Step Solution:

Verification / Alternative check:
ARCNET literature describes active hubs isolating segments and directing signals, enabling star-wired configurations versus pure bus wiring. This directional handling improved reliability and reach without implying network-layer routing.

Why Other Options Are Wrong:

• (a) ARCNET hubs did not perform path routing; they operated at the signaling/line level.
• (b) LAN expansion is constrained by media, timing, and addressing limits.
• (c) LANs target efficient local high-speed access, not “low-bandwidth channels.”
• (e) Not applicable since (d) is accurate.

Common Pitfalls:
Confusing hub signal steering/regeneration with routing; believing LANs can scale indefinitely without re-architecture; conflating WAN economic tradeoffs with LAN design goals.

Final Answer:
A characteristic of the hub architecture of ARCNET is directionalized transmission.