Michael,

I agree with you, that the window size should not be the problem.  
Retransmissions
occur for the following reasons:

- A TCP segment or returning ACK is dropped by a switch or router.
- The packet is dropped during transmission (CRC error)
- The data portion of the packet is corrupt (TCP checksum error)
- The recipient cannot buffer the packet (the sender is basically 
   ignoring the window size)
- The TCP segment gets fragmented and a fragment is dropped or corrupt.
- The ACK is slow to return and the sender retransmits the data.

I hope this helps.

Bill Baltas


Message-ID:
 <[EMAIL PROTECTED]>
Content-Type: text/plain; charset="utf-8"

Hello.

This may not be a Wireshark question - it is really a TCP question.  To
that end, if there is a good TCP forum to which I should post this, and
similar questions, please let me know.

Recently, there have been 2 occasions where colleagues have seen
retransmissions occurring, and they have been blaming this on the TCP
Window Size being too small, and want to increase it.  My response is:

- If the TCP Window size was too small, they would see conditions
where the receiver's window size goes to zero (or very small), and the
sender stops sending until a window update is received showing a bigger
window size.  They are NOT seeing this.
- I cannot think of a scenario where a too-small TCP Window size
would cause retransmissions.  (Can anyone in this forum???)

Can anyone comment on my assertions?  And, can you point me to a good
TCP forum?

Thx much!

Michael Feeny
Merrill Lynch

       
---------------------------------
Never miss a thing.   Make Yahoo your homepage.
_______________________________________________
Wireshark-users mailing list
Wireshark-users@wireshark.org
http://www.wireshark.org/mailman/listinfo/wireshark-users

Reply via email to