Question

a network administrator notices that the data transfer rates between devices in a 100base-tx fast ethernet network are not reaching the expected 100 mbps. the network uses switches, and all devices support fast ethernet.

what could the network administrator enable to improve the data transfer rates to the expected 100 mbps?

a autonegotiation on all devices
b replace switches with hubs
c full-duplex mode on all devices
d replace all cat 5 cables with fiber optic cables

Explanation:

Analyze the network scenario

The network uses 100BASE-TX Fast Ethernet, which has a theoretical maximum speed of 100 Mbps. The network administrator notices that actual data transfer rates are not reaching this expected speed, despite all devices supporting Fast Ethernet and being connected via switches.

Evaluate the impact of duplex settings

In Ethernet networks, devices can operate in either half-duplex or full-duplex mode.

• Half-duplex allows communication in only one direction at a time, which leads to collisions and significantly reduces effective throughput.
• Full-duplex allows simultaneous two-way communication, eliminating collisions and maximizing the utilization of the 100 Mbps bandwidth.

Enabling full-duplex mode on all devices ensures they can transmit and receive at 100 Mbps simultaneously without collision overhead.

Assess the alternative options

Using the Network Hubs knowledge point

• Option A: Autonegotiation can sometimes fail or misconfigure devices to half-duplex (duplex mismatch), so manually ensuring full-duplex is a more direct fix.
• Option B: Replacing switches with hubs would force all devices into half-duplex mode and introduce a single collision domain, severely degrading performance.
• Option D: Cat 5 cabling is fully rated for 100BASE-TX (100 Mbps) up to 100 meters, so replacing it with fiber optic cabling is unnecessary and expensive.

Determine the correct choice

Enabling full-duplex mode on all devices (Option C) is the most effective configuration change to achieve the expected 100 Mbps transfer rates.

Answer:

• (A) Autonegotiation on all devices
• (B) Replace switches with hubs
• (C) Full-duplex mode on all devices (Correct answer)
• (D) Replace all Cat 5 cables with fiber optic cables