How to optimize ADSL

The principle of ADSL optimization is the same as that of common Modem. It also modifies the network settings of the operating system so that the network settings of the operating system can give full play to their expected efficiency. The modification is mainly to modify Maxmtu, that is, to modify the maximum TCP/IP packet size. In the TCP/IP protocol, the data to be transmitted is divided into one data packet for transmission. The larger a single data packet, the smaller the proportion of useless data in actual transmission. However, in the transmission process, once the data packet is too large, the data in the data packet needs to be reloaded in groups, thus doubling the transmission time. In Windows, ADSL is used in the system. By default, the maximum TCP/IP packet size is set to 1500. The actual transmission unit of ADSL is slightly smaller than this value, using the default value will undoubtedly reduce transmission efficiency. It must be noted that the transmission unit size set by each ADSL service provider is often different, so manual modification will better meet your needs. The other is to modify the Defaultrcvwindow value, which defines the data acceptance buffer area. When the host accepts a certain amount of data packets and fills the buffer, it checks the data in the buffer according to the TCP/IP protocol. If any error occurs, the host needs to re-transmit the content of the entire buffer zone. Obviously, if the buffer area is too large, a packet error requires re-transmission of all data, resulting in a large waste of time on the two hosts. Being too small will not only occupy valuable network bandwidth, it will also make the entire system exhausted and do nothing to test and accept the work. Also, modify the Defaultttl value, which defines the packet survival time. From the perspective of reducing the burden, this value does not need to be adjusted too much. The following describes how to modify an instance: 1. to find the appropriate Maxmtu size, you 'd better use Netscan tools to find the DNS server address) and enter ping-f-l 1464 202.96.128.68 (here 1464 is the size of the test data packet, 202.96.128.68 is the IP address of the DNS server just obtained.) If "packet needs to be fragmented but df set" is returned, the value 1464 exceeds the maxmtu of the ADSL service provider, if data conflict fragments are generated, test the data packet size again until data such as "reply from 202.96.128.68: bytes = 1464 time = 36 ms ttl = 250" is returned, it can be determined that the value 1464 is suitable for the ADSL service provider. The value of Maxmtu is the value of the test plus 28, equal to 1492. 2. you should back up the registry before modifying the registry, or export the key value to be modified. If the modification is not satisfactory, import and restore the original settings. First, modify the Maxmtu and Maxmss values, click the start button, click Run, type regedit, and click OK to run the Registry Editor. Then, click "Open HKEYhtml #" target = _ blank> _ LOCAL_MACHINEsystem currentcontrolsetservicesclassettrans ", which contains keys 0001, 0002, and 0003. The TCP/IP Settings of different computers may be located in different locations, it may be 0001 or 0002. You can determine it based on driverdesc in it, and change Maxmtu to 1492 (enter a value based on the detection result in the previous step ), change Maxmss to 1452 (the maximum length of the information segment, that is, valid data in each data packet. The value can be a Maxmtu value minus the size of the reserved area, and the reserved area is 8 to 40 ), if you do not have these two values, you can add them by yourself. Both are string values. Then open HKEY_LOCAL_MACHINEsystem currentcontrolsetservicesvxdmstcp and change defaultrcvwindow to 371712 (this value is generally set to Maxmss multiplied by the network bandwidth integer except 8. Here the value is set to 2 Mbps, that is, to buffer the maximum data volume at a speed of about one second), change Defaultttl to 64 (optional range: 1 ~ 255), change Pmtublackholedetect to 0 (check whether the data transmission path has the setting for reinstalling the data packet group), change Tcp1323opts to 1, and change Sackopts to 1. If there is no such value, add it by yourself, it is also a string value. In HKEY_LOCAL_MACHINEsystemcurrentcontrolsetservicesvxd mstcpparameters, change Maxdupacks to 3 (any integer within 9, recommended value 3). If this value is not set, add it by yourself. This is a binary value. Once you confirm that there are no errors, you can close the Registry Editor, restart the computer, and connect to the network to test the effect.