CV0-003 · Question #144
After an administrator deployed a private cloud a couple of years ago, users have started reporting that the network is getting slower. The administrator looks at the monitoring tools and notices…
The correct answer is D. There are too many devices broadcasting on the subnet. Despite low per-port utilization, the large broadcast domain created by supernetting thousands of VMs generates excessive broadcast traffic that degrades overall network performance.
Question
After an administrator deployed a private cloud a couple of years ago, users have started reporting that the network is getting slower. The administrator looks at the monitoring tools and notices that, even though supernetting was used to allow for 8,000 more VMs, the most utilized switch port in the datacenter is only using 40% of its total throughput speed. Which of the following is MOST likely the problem?
Options
- AThe number of VMs using 1Pv4 is causing the network to crash.
- BEach host only has two links to the network, and they are becoming saturated.
- CThe network only has 4Gbps HBAs when all cloud networks should be using 10Gbps.
- DThere are too many devices broadcasting on the subnet.
How the community answered
(59 responses)- A19% (11)
- B5% (3)
- C8% (5)
- D68% (40)
Why each option
Despite low per-port utilization, the large broadcast domain created by supernetting thousands of VMs generates excessive broadcast traffic that degrades overall network performance.
IPv4 itself does not cause network crashes; the degradation stems from broadcast domain size, not the IP version in use.
The scenario states the most utilized port is only at 40% throughput, which directly rules out link saturation as the cause.
HBA speed relates to storage connectivity, and the 40% utilization figure indicates available bandwidth is not the bottleneck.
Supernetting 8,000 VMs into a single large subnet creates an enormous broadcast domain where every ARP request, DHCP broadcast, and similar layer-2 traffic is flooded to all devices on that subnet. This cumulative broadcast overhead consumes CPU cycles on every endpoint and saturates network processing capacity even when individual switch port throughput appears low.
Concept tested: Broadcast domain size impact on network performance
Source: https://www.cisco.com/c/en/us/support/docs/lan-switching/ethernet/10567-17.html
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