W3150A TCP - FTP issue


“back again”,

got UDP / DHCP working, but now:

i got trouble with file transfer (TCP - FTP), need it for firmware download.

Wireshark shows a lot of “TCP Dup Ack” and “TCP Retransmission”.

Also the W3150 chipset sends “ACK” always after retry counter was running down (0.4 sec.).

I would like to send you a screenshot of wireshark capture.

How can i do that ?

Many thanks.

Best Regards: Alfred Ferchau

Better attach Wireshark log.

Hi Eugeny,

thank you for you answer.

I would like to do that, but

i am not allowed to uploade something, i got message that “new users are not allowed to upload files”.

@ any admin: How can i manage that ?

Thank you.

Best regards: Alfred

Hi Eugeny,

o.k., now i got it, wireshark log is here:


some remarks:

It was running on with FileZilla 2.2.22 on XP, because the machine computers are XP.

Set Filter of wireshark to: ip.addr ==

FileZilla / PC is, Chipset W3150 is

Problem is :

1.: lots of TCP DUP ACK and TCP Retransmission

  1. If File transfere on port 20 starts, for every package it lasts precise 400 msec. for answer.

If i change RTR register to 200 ms, it lasts 200 ms.

(line 102 / 103 to 104: 0.4 sec.)

I do not understand that ?

Al of this is running perfect with old chipset W3100

Can you please give me any idea ?

Many Thanks,

Best regards: Alfred.

This is a sign that you have socket’s Sn_MR bit 5 (ND- no delayed ACK) reset. If it is reset, W5x00 family waits for timeout period expiration, and only then sends ACK. If you set this bit, ACK will be sent immediately after proper reception of the packet, and you will also see increase in performance. Please try setting this bit before anything else.

Hi Eugeny,

thank you very much !!

I will try that at once and tell you result !

Best regards: Alfred.