1.2. Differentiate Between Bandwidth and Throughput. 100-150 Practice Questions (Page 2)

Questions 6–10

1. 6expert · hard

   A network engineer is using Iperf to measure throughput between two hosts on a 10 Gbps link. The test shows 8 Gbps. The engineer wants to determine if the remaining 2 Gbps is due to protocol overhead or other factors. What is the best approach?

   • ARun Iperf with multiple parallel TCP streams.
   • BIncrease the TCP window size and rerun the test.
   • CCheck the switch's interface counters for errors.
   • DRun Iperf with UDP and compare the results to the TCP test.
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2. 7expert · hard

   A network administrator is troubleshooting a 1 Gbps link that is only achieving 500 Mbps throughput. Iperf tests show 500 Mbps with TCP and 950 Mbps with UDP. What is the most likely cause of the lower TCP throughput?

   • AThe UDP test is using more bandwidth than the link can handle, causing errors.
   • BThe TCP test is limited by the CPU of the hosts, while UDP is not.
   • CThe link's bandwidth is actually 500 Mbps for TCP and 950 Mbps for UDP.
   • DTCP congestion control and windowing are limiting throughput, possibly due to high latency or packet loss.
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4. 8application · medium

   A network administrator runs an internet speed test from a workstation and sees a download speed of 80 Mbps and an upload speed of 20 Mbps. The company's internet plan advertises 100 Mbps download and 100 Mbps upload. What does this result most likely indicate?

   • AThe bandwidth is 80 Mbps down and 20 Mbps up, so the plan is not delivering the advertised speeds.
   • BThe download throughput is lower than the plan's bandwidth, and the upload throughput is significantly lower, possibly due to plan limitations or network conditions.
   • CThe speed test measures latency, and the results show that the connection has high latency.
   • DThe upload speed is lower because the download speed uses most of the bandwidth, leaving less for uploads.
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5. 9application · medium

   A network engineer needs to measure the maximum achievable throughput between two servers on the same LAN. The engineer wants to isolate the effect of the network path from internet congestion. Which tool and approach should the engineer use?

   • APing the other server and use the round-trip time to calculate throughput
   • BRun an internet speed test from one server
   • CRun Iperf between the two servers on the LAN
   • DCopy a large file between the servers and divide the file size by the transfer time
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6. 10application · medium

   A network engineer is troubleshooting a database replication link between two data centers. The link has 1 Gbps bandwidth and 30 ms latency. The replication is transferring 100 GB of data and is taking much longer than expected. The engineer suspects the TCP window size is too small. What is the most likely effect of a small TCP window size on this link?

   • AIt increases latency, which directly reduces throughput.
   • BIt causes packet loss, which reduces throughput.
   • CIt reduces the bandwidth of the link.
   • DIt limits the amount of data in flight, reducing throughput on high-latency links.
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