You are connecting host computers to a switch with 10/100/1000Mbps Gigabit Ethernet ports. All of the ports are configured to autonegotiate speed and duplex settings. Which of the following will cause a mismatch condition? (Select the best answer.)

Last Updated on August 7, 2021 by Admin 3

You are connecting host computers to a switch with 10/100/1000Mbps Gigabit Ethernet ports. All of the ports are configured to autonegotiate speed and duplex settings.

Which of the following will cause a mismatch condition? (Select the best answer.)

  • connecting a NIC that is configured for halfduplex, 100Mbps operation
  • connecting a NIC that is configured for fullduplex, 100Mbps operation
  • connecting a NIC that is configured for fullduplex, 1000Mbps operation
  • connecting a NIC that is configured to autonegotiate duplex and speed settings
Explanation:
Connecting a network interface card (NIC) that is configured for fullduplex, 100Mbps operation will cause a mismatch condition because the duplex modes on the NIC and on the port will be different. A NIC that has been manually configured to use fullduplex or halfduplex mode does not respond to a port that is attempting to autonegotiate duplex settings. When the autonegotiating port receives no reply, it will use the default duplex settings for that speed. If the port detects that it should transmit at 10 Mbps or 100 Mbps, the port will default to halfduplex mode? if the port detects that it should transmit at 1000 Mbps, the port will default to fullduplex mode.
You can detect a duplex mismatch by monitoring a switch for %CDP-4-DUPLEXMISMATCH error messages. Additionally, you can issue the show interfacesinterface command, which displays counter information. If you see an abnormal increase in frame check sequence (FCS) errors and alignment errors on a halfduplex port, you should suspect a duplex mismatch. An abnormal increase in FCS errors and runts on a fullduplex port is also an indicator of a duplex mismatch.
Connecting a NIC that is configured for halfduplex, 100Mbps operation will not cause a mismatch condition.
The port will detect that it should transmit at 100 Mbps; therefore, it will default to halfduplex mode. Configuring both switch ports for halfduplex mode would enable only one port to send data at a time; however, communication could still occur, albeit slowly.
Connecting a NIC that is configured for fullduplex, 1000Mbps operation will not cause a mismatch condition. The port will detect that it should transmit at 1000 Mbps; therefore, it will default to fullduplex mode.
Connecting a NIC that is configured to autonegotiate duplex and speed settings will not cause a mismatch condition. When both sides of a link autonegotiate speed settings, they will select the highest speed common to both of them. When both sides of a link autonegotiate duplex settings, they will negotiate fullduplex mode if both ports support fullduplex operation. If either side of the link does not support fullduplex operation, the ports will negotiate halfduplex mode.

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