NetSpeed 1.0 4:51 PM 7/5/2004 ==================== --------------------------- VERY IMPORTANT INFORMATION --------------------------- 1) This program is for POWER USERS ONLY. If you don't know what you're doing, DON'T USE IT! 2) This documentation is beta, incomplete and plagerized. Please don't rely on it. ------ INTRO ------ NetSpeed is a program to tweak certain TCP/IP settings in the Windows Registry so as to optimize your Internet connection's bandwidth. It is simliar to Dr. TCP. When NetSpeed first starts, it records your original settings and stores them for reference later. This way, if you ever change a setting and it messes something up, you can always revert back to the original configuration. Just click "Load Original Settings" from the Presets menu. Depending on your Internet connection, certain settings may work better for you than others. Feel free to experiment with the program and see what settings makes your connection the fastest. REMEMBER: TO REVERT BACK TO YOU ORIGINAL SETTINGS, CLICK "LOAD ORIGINAL SETTINGS" UNDER THE PRESETS MENU. ----------- SETTINGS ----------- <<< TCP Receive Window (RWIN) >>> The TCP Receive Window size is the amount of receive data (in bytes) that can be buffered at one time on a connection. The sending host can send only that amount of data before waiting for an acknowledgment and window update from the receiving host. Matching the receive window to even increments of the MSS increases the percentage of full-sized TCP segments utilized during bulk data transmission. MSS is the MaxMTU - 40 bytes for TCP and IP headers. <<< Max. Duplicate ACKS >>> This allows for faster re-transmission of packets when lost. I leave this setting blank. (blank = 3 for Win98/98SE/ME and blank = 2 for Win2000). <<< TTL >>> Time to Live. The Time To Live, or TTL, is a value that indicates how many hops a packet can traverse before it is considered lost or misrouted. The upper bound for this is 32 by default, and many routers will force a packet that comes in with a TTL higher than 32 to be dropped back to 32. There's no harm in setting it higher, but if it's simply scaled back by the routers on your ISP then it's pointless to change this. Some of the programs I experimented with recommended setting this as high as 128 -- probably not harmful in itself, though, but I could not verify that anything I was sending with a TTL that high was in fact being forwarded intact. Or more precisely, I couldn't insure that they were still using the TTL I had set, or were using a "truncated" TTL (like 32 or less instead of 128). <<< Windows Scaling >>> 65535 is the highest value that you can set your Rwin to, without having to use windows scaling. Scaling is needed to enter any number higher than 65535. Optimal setting: Default (off). <<< Time Stamping >>> This setting may or may not improve performance. If you have a line where latency varies a lot, time stamping may be beneficial.......experiment with it to make sure. Optimal setting: Default (off). <<< Selective Acks >>> This improves the speed of lines that tend to lose packets, by re-transmitting only packets that were lost, if any. Optimal setting: default ( on). <<< Path MTU Discovery >>> This automatically sets your MTU to suit the type of line that you have (dial-up or broadband). The highest MTU that you can set is 1500. Optimal setting: default ( on). <<< Black Hole Detection >>> This discovers routers on the web that cause MTU Discovery to work sub-optimally. Optimal setting: Default (off). ----------------- Adapter Settings ----------------- This section is used to set adapter-specific MTU (Maximum Transmission Unit). <<< MTU >>> An MTU is a parameter that specifies how much data a frame for a particular network can carry. This parameter becomes an issue when networks are interconnected and the networks have different MTU sizes. When a datagram arrives at a router that must be forwarded onto a network with a smaller MTU size, the router fragments the packet into pieces that will fit into the frames of the next-hop network. --------------------------- FOR ADDITIONAL INFORMATION --------------------------- http://www.speedguide.net/ http://www.speedguide.net/articles.php?category=93 http://www.exodus-dev.com/techtips/advanced_tcp.htm http://www.erg.abdn.ac.uk/users/gorry/course/inet-pages/mtu.html http://www.extremetech.com/article2/0,1558,1153608,00.asp