Network Slowness Troubleshooting

ProjectsCase: – In the above scenario, if PC 1( is trying to upload some files using FTP to PC2 (, however, speed is not so good and consistent. Ping from machine 1 to machine is without drops. What’s the best way to resolve Network Slowness?


  1. Verify the delay factor while pinging to PC2 to from PC1. Delay should not be very high and should remain within the normal value. Also try to know about the size of data being uploaded.
  2. Verify the Traceroute output to PC2 from PC1 and observe at what level delay suddenly increase.
  3. If file size is not that big and still it causing slowness then try to isolate the issue by pinging to fa0/0 , s0/0 , and from PC1. Observe at what level we see delay in ping.
  4. If delay still exists, then check the duplex and speed settings configured at interfaces of PC1 , PC2 and other routing interfaces. Sometime, we need to manually set the duplex/speed if set to auto mode.
  5. Verify if there are CRC, input or output packet drops or errors are seen on interfaces. Check using show interface | Include CRC|drops|errors. Also check the Load and reliability of interfaces. Reliability should be 255/255 , if load is high  then probability may be of its high usage by some other sessions or data transfer. There is a limit of every interface to send/receive data and that depends upon the ASIC of the interface.
  6. Verify that there is no high utilization of Memory or CPU in every device. There could be some process consuming memory.
  7. Verify whether workstations participating in data transfer are capable of handling such high transfer or verify what application is being used for transfer on PC1 and PC2. Low CPU and Memory also cause network slowness.


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