Optimization of parameters related to ADSL Internet Access Mode

Because ADSL uses the PPPoE protocol, this Protocol has the characteristics of a LAN, but not completely equal to the LAN protocol. Therefore, we can use this to optimize ADSL by modifying the relevant parameters in the registry. The most important optimization parameters are MaxMTU, ultrultrcvwindow, and DefaultTTL.

1. MaxMTU is the largest TCP/IP transmission unit. In the TCP/IP protocol, data to be transmitted is divided into smaller groups for transmission. The size of each group is 576 bytes. In Windows, the default byte is 1500, which is the Ethernet grouping standard.
The PPPoE used by ADSL is slightly smaller than this value. According to the slight difference obtained by the ISP, using the default value will reduce the transmission efficiency. The location of MaxMTU in the registry: HKEY_LOCAL_MACHINE \ System \ CurrentControlSet \ Services \ Class \ NetTrans \ 00yy, key name: MaxMTU. Here, yy is the entry of TCP/IP, which varies with the settings, generally between 00 and 30. How can I determine and match the MTU value of the ISP for optimization? In fact, it is very easy to use the ping command to obtain this value. Ping www.yesky.com-f-l 1500 to send data grouped by 1500 to www.yesky.com, and check whether data fragments generated by different groups are found. If yes, the group value is decreased, finally, we can find the matched MaxMTU. This value is the most critical part of ADSL optimization.

2. DefaultRcvWindow is the size of the default transmission unit buffer. If the buffer is too small, it will cause group blocking and reduce transmission efficiency. The buffer zone is too large. An error in a group may cause all partitions in the buffer zone to be discarded and re-transmitted, reducing the efficiency. The Size of this value is related to the Modem speed, preferably an integer multiple of MSS (Maximum Segment Size, Maximum number of groups, equal to MxaMTU minus 40 bytes of address information? Position of DefaultRcvWindow in the Registry: HKEY_LOCAL_MACHINE \ System \ CurrentControlSet \ Services \ VxD \ MSTCP? Key: DefaultRcvWindow.

3. DefaultTTL is the lifetime of a TCP/IP group. If the transmission time of a group over the INTERNET exceeds the lifetime of the group, the group will be discarded. Changing DefaultTTL to a greater value facilitates further transmission of information over the INTERNET. Position of DefaultTTL in the Registry: HKEY_LOCAL_MACHINE \ System \ CurrentControlSet \ Services \ VxD \ MSTCP; key name: DefaultTTL.

By optimizing these parameters, you can improve the efficiency of ADSL.

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