Please Whitelist This Site?

I know everyone hates ads. But please understand that I am providing premium content for free that takes hundreds of hours of time to research and write. I don't want to go to a pay-only model like some sites, but when more and more people block ads, I end up working for free. And I have a family to support, just like you. :)

If you like The TCP/IP Guide, please consider the download version. It's priced very economically and you can read all of it in a convenient format without ads.

If you want to use this site for free, I'd be grateful if you could add the site to the whitelist for Adblock. To do so, just open the Adblock menu and select "Disable on tcpipguide.com". Or go to the Tools menu and select "Adblock Plus Preferences...". Then click "Add Filter..." at the bottom, and add this string: "@@||tcpipguide.com^$document". Then just click OK.

Thanks for your understanding!

Sincerely, Charles Kozierok
Author and Publisher, The TCP/IP Guide


NOTE: Using software to mass-download the site degrades the server and is prohibited.
If you want to read The TCP/IP Guide offline, please consider licensing it. Thank you.

The Book is Here... and Now On Sale!

Get The TCP/IP Guide for your own computer.
The TCP/IP Guide

Custom Search







Table Of Contents  The TCP/IP Guide
 9  TCP/IP Lower-Layer (Interface, Internet and Transport) Protocols (OSI Layers 2, 3 and 4)
      9  TCP/IP Transport Layer Protocols
           9  Transmission Control Protocol (TCP) and User Datagram Protocol (UDP)
                9  TCP/IP Transmission Control Protocol (TCP)
                     9  TCP Reliability and Flow Control Features and Protocol Modifications

Previous Topic/Section
TCP Adaptive Retransmission and Retransmission Timer Calculations
Previous Page
Pages in Current Topic/Section
12
3
4
Next Page
TCP Window Management Issues
Next Topic/Section

TCP Window Size Adjustment and Flow Control
(Page 3 of 4)

Reducing Send Window Size To Stop The Sending of New Data

What if the server is so bogged down that it can't process any of the bytes received? Let’s suppose that the next transmission from the client is 180 bytes in size, but the server is so busy it can’t remove any of them. It could buffer the 180 bytes and in the acknowledgment it sends for those bytes, reduce the window size by the same amount: from 260 to 80. When the client received the acknowledgment for 180 bytes it would see the window size had reduced by 180 bytes as well. It would “slide” its window by the same amount as the window size was reduced! This is effectively like the server saying “I acknowledge receipt of 180 bytes, but I am not allowing you to send any new bytes to replace them”.

Another way of looking at this is that the left edge of the window slides 180 bytes while the right edge remained fixed. And as long as the right edge of the window doesn't move, the client can't send any more data than it could before receipt of the acknowledgment. This is the middle exchange (Steps #4 to #6) in Figure 226.


Previous Topic/Section
TCP Adaptive Retransmission and Retransmission Timer Calculations
Previous Page
Pages in Current Topic/Section
12
3
4
Next Page
TCP Window Management Issues
Next Topic/Section

If you find The TCP/IP Guide useful, please consider making a small Paypal donation to help the site, using one of the buttons below. You can also donate a custom amount using the far right button (not less than $1 please, or PayPal gets most/all of your money!) In lieu of a larger donation, you may wish to consider purchasing a download license of The TCP/IP Guide. Thanks for your support!
Donate $2
Donate $5
Donate $10
Donate $20
Donate $30
Donate: $



Home - Table Of Contents - Contact Us

The TCP/IP Guide (http://www.TCPIPGuide.com)
Version 3.0 - Version Date: September 20, 2005

© Copyright 2001-2005 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.