TCP stops sending ACKs after 32 mesg...

Hi,

    It has been more than a week since I posted this query to the LINUX group and haven't heard anything from the group-side in this context. Is my query under processing/observation OR something else??

Hope to get some positive response from your side this time!

Thanks And Regards
Saurabh

----- Original Message ----- 
From: Saurabh Bansal 
To: netdev@oss.sgi.com 
Cc: linux-net@vger.kernel.org 
Sent: Wednesday, August 21, 2002 1:26 PM


Hi all,

    I did this experiment with the a set of two processes behaving as a sender/receiver set on the same Linux machine. What the experiment was that---

"The sender has to send some fixed-size (20 bytes) mesgs to the receiver but the receiver has not to pick-up anyone of them."

 What has been observed is, TCP buffers the first 32 messages into the receive socket queue of receiver, AND THEN it stops sending ack's for next mesg. As a result, the sender keeps on trying to send the 33rd mesg, but gets no ack's and connection gets down within 15-20 minutes. Another important observations about this experiment are :

1) These two processes were running on the same Linux system with kernel version 2.2.xx. This problem doesn't come with Linux-kernel 2.4.xx.

2) If these processes are run on different Linux m/c's with kernel 2.2.xx, the problem doesn't appear.

3) The socket APIs used for sending/receiving mesg are send()/recv().

4) The problem has no relevance with the size of mesg. I have seen the same behavior with 1-byte mesg to 1k-byte mesg.

Can anyone tell me if there is any bug/limitation with the Linux-kernel 2.2.xx in comparison to kernel 2.4.xx in the above problem-context??


Saurabh Bansal