WAN technologies (Frame Relay): By default, a Frame Relay WAN is categorized as what type of Layer 2 physical topology?
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APoint-to-point
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BBroadcast multi-access
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CNon-broadcast multi-access
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DNon-broadcast multipoint
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ERing
Answer
Correct Answer: Non-broadcast multi-access
Explanation
Introduction / Context:Legacy WAN services like Frame Relay shaped many CCNA-era designs. Understanding their logical/physical characteristics is key to choosing routing protocols and neighbor discovery behavior.
Given Data / Assumptions:
- Technology: Frame Relay (L2 WAN service with PVCs).
- “Default” behavior as seen by routing protocols.
Concept / Approach:Frame Relay is a Non-Broadcast Multi-Access (NBMA) network. Multiple nodes share the provider cloud, but the medium does not support broadcast/multicast natively across all neighbors. This affects protocols like OSPF/EIGRP, which may need manual neighbor statements or special network types.
Step-by-Step Solution:
Classify the medium: multi-access (many routers can attach).Note that it does not inherently forward L2 broadcast to all peers.Therefore, it is NBMA by default.Verification / Alternative check:Classic certification texts state “Frame Relay is NBMA,” guiding choices like OSPF point-to-multipoint or static neighbor settings.
Why Other Options Are Wrong:
- Point-to-point: Only if configured as such per PVC; not the default.
- Broadcast multi-access: Contradicts NBMA nature.
- Non-broadcast multipoint: Terminology mix; standard term is NBMA.
- Ring: Not applicable.
Common Pitfalls:Assuming Ethernet-like broadcast behavior; forgetting to adapt routing protocol settings for NBMA.
Final Answer:Non-broadcast multi-access