CompTIA Network+ N10-007 Exam: Troubleshooting Gigabit Fiber Speeds

Troubleshooting Gigabit Fiber Speeds

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Question

Ann, a customer, recently upgraded her SOHO Internet to gigabit fiber from cable.

She was previously getting speeds around 75Mbps down and 25Mbps up.

After the upgrade, Ann runs a speed test on her desktop and gets results of 1000Mbps down and 100Mbps up.

A technician connects directly to the router and sees the correct 1000Mbps speeds.

Which of the following is MOST likely the cause? (Choose two.)

A.

All ports should be configured for full duplex. B.

There is a 10/100 switch on the network. C.

The connections are using Cat 5 cable. D.

The connections are using Cat 6 cable. E.

There is a transceiver mismatch at the fiber termination point. F.

Signal attenuation on the new fiber has reached the upper limits.

AC.

Explanations

Ann, a customer, recently upgraded her SOHO Internet to gigabit fiber from cable.

She was previously getting speeds around 75Mbps down and 25Mbps up.

After the upgrade, Ann runs a speed test on her desktop and gets results of 1000Mbps down and 100Mbps up.

A technician connects directly to the router and sees the correct 1000Mbps speeds.

Which of the following is MOST likely the cause? (Choose two.)

A.

All ports should be configured for full duplex.

B.

There is a 10/100 switch on the network.

C.

The connections are using Cat 5 cable.

D.

The connections are using Cat 6 cable.

E.

There is a transceiver mismatch at the fiber termination point.

F.

Signal attenuation on the new fiber has reached the upper limits.

AC.

The two most likely causes for the difference in speed test results between Ann's desktop and the direct connection to the router are:

A. All ports should be configured for full duplex. B. There is a 10/100 switch on the network.

Explanation:

A. All ports should be configured for full duplex: Full duplex is a communication mode that allows simultaneous two-way communication between devices. If a device's network interface is set to half duplex, it can only communicate in one direction at a time, resulting in slower network performance. So, if the desktop's network interface is set to half duplex, it may be limiting the speed to 100Mbps, even though the router and the fiber connection are capable of higher speeds. Therefore, it is essential to configure all ports for full duplex to take advantage of the gigabit speed.

B. There is a 10/100 switch on the network: A 10/100 switch is a network switch that supports only 10Mbps and 100Mbps Ethernet connections. If Ann's network includes a 10/100 switch between her desktop and the router, it may be limiting the speed to 100Mbps, even though the router and the fiber connection are capable of higher speeds. Therefore, if a 10/100 switch is present in the network, it should be replaced with a gigabit switch to achieve higher speeds.

C. The connections are using Cat 5 cable: Cat 5 cable can support up to 100Mbps and is not capable of gigabit speeds. However, in this case, the speed test result shows 1000Mbps, which indicates that the cable is not the limiting factor.

D. The connections are using Cat 6 cable: Cat 6 cable can support up to 10Gbps and is more than capable of supporting gigabit speeds. Therefore, if the cable is Cat 6, it is not the limiting factor.

E. There is a transceiver mismatch at the fiber termination point: A transceiver is a device that converts electrical signals to optical signals and vice versa. If there is a mismatch between the transceivers at either end of the fiber optic connection, it can result in reduced speed or no connection at all. However, if the technician sees the correct 1000Mbps speed when connected directly to the router, it indicates that the transceiver at the router end is working correctly, and the issue is likely not related to a transceiver mismatch.

F. Signal attenuation on the new fiber has reached the upper limits: Signal attenuation refers to the loss of signal strength over a distance in a fiber optic connection. If the signal strength drops too low, it can result in reduced speed or no connection at all. However, if the technician sees the correct 1000Mbps speed when connected directly to the router, it indicates that the signal strength is not the limiting factor.

In conclusion, the two most likely causes for the difference in speed test results are a half-duplex configuration on the desktop's network interface or the presence of a 10/100 switch in the network.