How to troubleshoot multi-Gbps cabling issues

This page shows you how to determine if your network cabling is preventing you from achieving multi-Gbps speeds.

Symptoms

Sophos Switch supports speeds up to 10 Gbps, depending on the model. To achieve these speeds, your network must meet certain requirements. See Network cable design and component planning. If you don't meet these requirements, you may experience the following symptoms:

Unstable links.
Links are stable, but speeds are lower than expected. For example, a 2.5 Gbps connection may link at 1 Gbps.
Links are stable and connected at the expected speed, but the packet error rate is extremely high.

Troubleshooting

Sophos Switch has CLI commands for measuring network traffic performance and reliability. If you're experiencing poor network performance, generate some constant network traffic and run the following tests:

Check network link stability by running the following command:
```
show interfaces status
```
Run the command several times and compare the results in the Speed column to ensure the link speed remains constant. If it fluctuates, inspect your network cabling.
Check for packet errors by running the following command, replacing <port> with the number of the port you want to check:
```
show interfaces gigabitethernet 0/<port> counters
```
Check for errors in the InErrs column. A non-zero number in this column means you should inspect your network cabling.

Note

Sophos Switches are compliant with IEEE 802.3 BER of 10^-12.
Check flow control by running the following command, replacing <port> with the number of the port you want to check:
```
show interfaces gigabitethernet 0/<port> flowcontrol
```
This command shows you if the transmit or receive side is generating flow control frames. Run the command several times and monitor the results in the Tx Pause and Rx Pause columns. If either side generates flow control frames, check the port settings to ensure it can handle the expected speed.