TFTP error

Hi,

I tried to upgrade the IOS for 4510 Switch. I have upgraded it successfully.

But while upgrading I got an error Message in the TFTP server. I have seen this error message lot of time but I don’t know why it is coming.

Ack block 1944 ignored (received twice)
Ack block 1944 ignored (received twice)

Found this website which gives a brief explination of tftp www.softlookup.com/tutorial/tcp_ip/ch06.asp#E69E90

From what i have been reading about TCP, it looks like the TFTP deamon is receiving duplicate ACKnowledgements to data that is being sent.

Still in middle of reading up on the inner workings of TCP/IP so i wouldn't even attempt to explain what causes a DUP ACK as i am not 100% sure myself.

Hope it helps

Cheers