Difficulty: Easy
Correct Answer: True
Explanation:
Introduction / Context:
Switch fabric design impacts how well a switch sustains throughput as offered load increases. Two common architectures are crossbar (non-blocking port-to-port paths) and shared or cell-based backplanes (where packets are segmented into fixed-size cells and traverse shared internal bandwidth).
Given Data / Assumptions:
Concept / Approach:
Crossbar fabrics allow many non-conflicting port pairs to communicate simultaneously, reducing head-of-line blocking and internal contention. Under overload, scheduling can still allocate paths efficiently for parallel conversations. Cell-based backplanes incur segmentation/reassembly overhead, potential internal contention at shared memory or buses, and can suffer more from head-of-line blocking when queues back up.
Step-by-Step Solution:
Verification / Alternative check:
Vendor whitepapers and queueing models show crossbar/Clos fabrics approaching non-blocking behavior, whereas shared-memory or bus-based designs saturate earlier.
Why Other Options Are Wrong:
Common Pitfalls:
Confusing front-panel line-rate claims with sustained internal switching capacity; internal architecture determines behavior under stress.
Final Answer:
True
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