But I stopped using TFTP for IOS image upgrade, instead get used to FTP method. 3850-2# copy usbflash0:cat3k_caa-universalk9.SPA.03.03.02.SE. flash:Ĭopy in progress.CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCĬCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCĬCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCĢ57243236 bytes copied in 59.890 secs ( 4295262 bytes/sec)īased on the above, I did not have clear understanding why TFTP is that slow in this latest & greatest 3850 switch.

If it is new installation, you can use this method, but in a existing network IOS upgrade, it is practically difficult to use this method as you have to physically attach USB on to the switches. As you can see file transferred within 60s & I got around 32.8Mbps (4295262 Bytes/Sec) transfer rate. Here is the file transfer rate If I do it via USB stick directly attached to the switch. This time it took only around 261s (4.3 min) & copied 7.5 Mbps ( 984249 Bytes/Sec) which is much better than the TFTP transfer speed which was ~ 1.3 Mbps. Then I did the same file transfer via FTP. Tried with different TFTP servers, different Operating Systems (Windows, MAC OX,etc) & every time it took more than 25 mins. As shown in the below it took 1548s (~ 26min) to copy the image via TFTP & my transfer speed was ~ 1.3Mbps ( 166150 Bytes/Sec)ĭestination filename ? I have come across this issue multiple times & it almost took more than 20 min to copy ~250MB image to switch flash when using TFTP. If you have done IOS upgrade of this latest Cisco 3850 switch you may noticed a TFTP file transfer is taking longer time.

Cisco copy tftp flash