Which statement accurately describes the result of disabling restrictions on oversubscription ratios on Cisco MDS 9000 Series Fibre Channel switching modules?

Question

Options

• AThe bandwidth allocated to shared ports is proportionate to the configured speed of the ports.
• BA port-group can contain a single port only.
• CThe bandwidth allocation of the shared ports is equal to the lowest configured bandwidth.
• DQoS can be configured.

• A
  93% (14)
• D
  7% (1)

Explanation

On Cisco MDS 9000 switching modules, ports in a port group share a fixed backplane bandwidth. When you disable restrictions on oversubscription ratios, the switch distributes that shared bandwidth proportionally - a port configured at 4 Gbps receives twice the share of a port configured at 2 Gbps - making A correct.

Why the distractors are wrong:

• B is incorrect because port group membership (how many ports are in a group) is a hardware topology fact, unaffected by oversubscription ratio settings.
• C describes the behavior when restrictions are enabled - equalizing bandwidth to the lowest common denominator to enforce fairness caps, which is the opposite of what disabling does.
• D is a red herring; QoS configurability is independent of oversubscription ratio restrictions and is not unlocked by disabling them.

Memory tip: Think of it as "proportional = proportionate to speed." Disabling restrictions removes the equalizer, so faster ports pull more bandwidth - like wider pipes getting more water flow. The key word in the question is disabled, which removes artificial caps and lets port speed drive allocation.

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