Windows tuning typically includes tuning of the Internet connection. Many parameters influence the connection's speed and quality. First, the MTU and MSS value are such parameters. The MTU determines the maximum size of a data packet that is sent over the line (or air). The MSS value specifies the maximum size of a data segment, a further breakdown of data packets into individual segments.
A much more important value for the throughput is the so-called RWIN value. Since the TCP protocol is mainly used on the Internet, it is a packet-switched network. Data will be put in packages marked with the sender's and recipient's address and other control data and sent on their way through the net. To let the sender know that his package has arrived, he demands an acknowledgment from the receiver. The effort would be very high to send a confirmation for each packet. The RWIN value (Receive Window) determines how many packets the sender can send without a confirmation. After this amount of packets the receiver has to send the confirmation. If the sender does not receive the confirmation, he will re-send all packets and wait for a confirmation again. With a small RWIN value the many confirmation packets slow down the connection, because the sender has to wait for every confirmation before he can send the next packets. A too large RWIN value can also lead to problems. If a loss of data or erroneous data occurs, a large amount of packets must be sent again. On the Internet it does happen regularly that individual packets are faulty or not delivered.
To get the best of your Internet connection, you need to find an optimal value for the RWIN paramter. There are different opinions and formulas which are all similar. However, since Windows Vista the subject of Internet tuning became unimportant: Vista's TCP/IP implementation has the ability to auto-tune itself. It dynamically adjusts all key parameters to the connection's capacity and quality. Windows Vista (and of course the successor Windows 7) independently find an optimal RWIN value, without the need for the user to have additional tools for Internet tuning. Therefore, WinLube no more has a module for Internet tuning, since this is no longer needed with Windows Vista and Windows 7.
