3560 tftp errors - what does O mean?

[paul.matthews]

Some colleagues are trying to upgrade a 3560 switch and are having problems. Instead of the nice !s to say all is going well, or the normal .s when there is a problem they are saying they are getting Os - anyone know what that means?

Ta.

[Network713]

Used my desktop Win10, tftpd64. I deleted the current IOS on 3560, then did a tftp and got !OO!OO!OO!OO!OO!OO!OOO!OO!... [timed out].

I tried changing the tftpd64 settings, timeout 6 & retransmit 10 (like others suggested, it didn't help).

3560 doesn't have the command "ip tftp block-size xxxx"

The solution for me was to use another tftp server and program, I used my Solarwinds server with Solarwinds tftp and it was all good (but it took a long time). I know it is best to do it on a local pc, but I don't have that option, I'm doing the tftp over a WAN link.

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WS-C3560V2-48PS#delete /recursive /force flash:c3560-ipbasek9-mz.122-55.SE12.bin

WS-C3560V2-48PS#dir
Directory of flash:/

2 -rwx 796 Aug 30 2017 15:17:17 -05:00 vlan.dat
3 -rwx 5511 Sep 21 2020 17:32:19 -05:00 private-config.text
5 -rwx 4120 Sep 21 2020 17:32:19 -05:00 multiple-fs
6 drwx 512 May 1 1993 13:39:31 -05:00 crashinfo_ext
8 -rwx 64627 Sep 21 2020 17:32:18 -05:00 config.text

WS-C3560V2-48PS#copy tftp://10.10.10.247/c3560-ipbasek9-mz.150-2.SE11.bin flash:c3560-ipbasek9-mz.150-2.SE11.bin
Destination filename [c3560-ipbasek9-mz.150-2.SE11.bin]?
Accessing tftp://10.10.15.247/c3560-ipbasek9-mz.150-2.SE11.bin...
Loading c3560-ipbasek9-mz.150-2.SE11.bin from 10.10.15.247 (via Vlan10): !OO!OO!OO!OO!OO!OO!OOO!OO!... [timed out]

WS-C3560V2-48PS#copy tftp://10.10.10.100/c3560-ipbasek9-mz.150-2.SE11.bin flash:c3560-ipbasek9-mz.150-2.SE11.bin
Destination filename [c3560-ipbasek9-mz.150-2.SE11.bin]?
Accessing tftp://10.10.18.100/c3560-ipbasek9-mz.150-2.SE11.bin...
Loading c3560-ipbasek9-mz.150-2.SE11.bin from 10.10.18.100 (via Vlan10): !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!O!!!!!!!!!!
[OK - 16664448 bytes]
16664448 bytes copied in 1200.217 secs (13885 bytes/sec)

WS-C3560V2-48PS#verify /md5 flash:c3560-ipbasek9-mz.150-2.SE11.bin
.........................................................................................................................................................................Done!
verify /md5 (flash:c3560-ipbasek9-mz.150-2.SE11.bin) = b81d9bfd47be75d966d122af60003fef

[sSiDs]

Switch Ports Model SW Version SW Image
------ ----- ----- ---------- ----------
* 1 30 WS-C3560X-24 15.2(4)E10 C3560E-UNIVERSALK9-M

Configuration register is 0xF

ST-LAB-SW-02#conf t
Enter configuration commands, one per line. End with CNTL/Z.
ST-LAB-SW-02(config)#ip tftp ?
blocksize Specify TFTP client blocksize
boot-interface Force interface to use for TFTP booting
min-timeout Set minimum timeout period for retransmission
source-interface Specify interface for source address in TFTP connections

ST-LAB-SW-02(config)#ip tftp bl
ST-LAB-SW-02(config)#ip tftp blocksize 1024
ST-LAB-SW-02(config)#end
ST-LAB-SW-02#wr
Building configuration...
[OK]!

[Joseph W. Doherty]

". . . (but it took a long time).  . . . I'm doing the tftp over a WAN link."

That's common with across WAN, due to the combination that TFTP doesn't "window" transmit and WAN latency.  TCP based file copy options, like FTP, generally, run much faster across WAN links.

[Mike_Rame]

When i took the IOS image from the Catalyst 9410R tftp server with only one swithch, it was ok,100% "!" When i tried to multitask, and access the tftp from 2 switches at the same time, about 5-10% of the marks were "." or "0". The links are 2x10G so in my case the read speed of the flashdrive was the bottleneck.

[Richard Burts]

Thanks for sharing your insight into this issue. This is an interesting perspective.

[Joseph W. Doherty]

Don't doubt your observations, or disbelieving a flashdrive could be a bottleneck, but I wouldn't expect a flash drive's read speed would cause either timeouts or out-of-sequence delivery errors, concurrently pulling from a flashdrive.

Was PMTUD enabled on the source device?

What were the CPU stats like for your single and dual access runs?

Have you ever tried similar test setting up the Cisco source device as a FTP server?