C3650 tftp-server question

[warfieldn]

Hi All,

 I'm trying to transfer an IOS image in .bin file from one Catalyst 3650 to another.  . The transfer is happening but not as fast as I'm expecting.

Switch 1 (server) > Switch 2 

Below are the relevant configs.

Switch 1:

tftp-server flash:cat3k_caa-universalk9.SPA.03.06.05.E.152-2.E5.bin

ip tftp blocksize 8192

Switch 2:

ip tftp blocksize 8192

Running a  'debug tftp packets' on Switch 1 gives the below output:

May 1 14:27:40.287 EDT: TFTP: Sending block 7565 (retry 0), len 512, socket_id 0x3B5FACCC
May 1 14:27:40.292 EDT: TFTP: Received ACK for block 7565, socket_id 0x3B5FACCC

Because I'm seeing 'len 512' in the debug output I'm assuming I either missed some relevant config to make the transfer happen at a higher blocksize or it's just not working as expected. 

Anyone got any ideas? 

[Georg Pauwen]

Hello,

TFTP is the slowest protocol. Try FTP instead. That said, changing the blocksize is the recommended fix for slow TFTP transfers, apparently in your case it doesn' work...

What is the uptime of the switches ?

[warfieldn]

Georg,

 Switch 1 - 27weeks  

 Switch 2 - 6 weeks

I do not believe Catalyst 3650 can act as ftp server. If it can can you provide the configuration as I've been unable to find it.

Thanks.

[Georg Pauwen]

Hello,

the idea was that when switches have very long uptimes, they can become slow to respond. 27 and 6 weeks is not a problem.

That said, why don't you copy to an FTP server first and then back to the other switch ?

[warfieldn]

There is no FTP server on site and a very low bandwidth WAN connection. There's also 3-4 devices per site the IOS needed to load to. Hence why we wanted to go switch to switch once getting the file there initially.

We eventually just pushed the files overnight and dealt with the slowness.

[Georg Pauwen]

Hello,

thanks for letting us know. 

[Diego Cabanas]

Sorry, I know maybe it is too late, but you need to modify the block-side in the tftp in order to sent the files faster. In this wait, the same file that spends 5 minutes with the blocksize 512, it is going to be transfer in 10 seconds.

Switch(config)#ip tftp blocksize ?
<512-8192> blocksize value

Switch(config)#ip tftp blocksize 8192