TFTP and FTP speed over WAN

Unanswered Question
Oct 8th, 2009

Hello Folks,

I have 10Mbps WAN link speed and with no qos and very light traffic, both FTP and TFTP image upgrade are very slow. I am getting speeds of only 55Kbytes/sec and 50Kbytes/sec respectively. I thought FTP will be much faster (even with 12 bytes per packet more overahead) than TFTP, because of no small 512KB packets used by TFTP and ack requirements for each packet transmitted, but speed seems almost same in both cases.

I am using tftpd32 (recommended by Cisco in so many docs) for TFTP server and FTPDMIN and FreeFTPd and results are similar. Is it limitation of Cisco routers / switches that you can not have faster than 50 to 55Kbytes ( less than 500kbps) for IOS upgrades?

Please advise.


I have this problem too.
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David Hornstein Thu, 10/08/2009 - 13:39

Hi dpsharma

You are upgrading Flash on a router at 55Kbytes per second, or 55,000 x8 bits or 440,000 bits per second,  being burnt to flash over a WAN interface.  Sound quick to me.

In a example below, taken from a 2900 switch with the TFTP server on the same LAN,  we have transfer rate of  23Kbytes per second.

switch#copy tftp:// 
Destination filename [c2900xl-c3h2s-mz.120-5.WC8.bin]?
Accessing tftp://
Loading c2900xl-c3h2s-mz.120-5.WC8.bin from (via VLAN1)

!--- Output suppressed.

[OK - 1803565 bytes]

1803565 bytes copied in 78.124 secs (23122 bytes/sec)

I would think that the limitation you are finding is writing a operating system onto a flash card.

Are you really annoyed , or just inquisitive about time it takes up upgrade successfully  a router remotely?

I think that the remote upgrade is much faster and more eco-friendly than having to drive on site to do the upgrade. :)

regards Dave

dpsharma Thu, 10/08/2009 - 15:14

Much appreciate Dave for your detailed response. I was just curious and also worried that I will have to first delete image from flash (not enough room to accomodate two images) and then leave router running while upgrading over DMVPN and for a 36MB image that could take over 15 minutes at these slow speeds. If the vpn tunnels breaks because of internet circuit issues, I can restart copy process, but if meanwhile there is power outage situation (though we believe backup should last for 10 minutes at remote sites) for few minutes, then router can not boot up. So I was hoping that probably ftp will be faster. But you indicated that limitation is the image being written to flash.

Anyway, we can copy image directly to ram (and that will be faster and from there to local flash) atleast to take care of WAN outage?

Thanks again for your prompt support.


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