下行揭露电信ADSL上行 下行速度之谜（Exposing the mysteries of telecom ADSL uplink and downlink）

揭露电信ADSL上行下行速度之谜Exposing the mysteries oftelecom ADSL uplink and downlink

Exposing the enigma of telecom ADSL uplink / downlink speedOnce the civil cable pulled up a ADSL4MBit, according to 8 (Bit)=1 bytes (Byte) conversion, 4MBit=4096KBit=512KByte broadband,so theoretically 4M download the maximum speed should be 512K/seconds, then because of some other factors, the actualdownload speed is normal in 500K/ seconds. The company to 10employees, but found that since the cable access network isalways in a state of paralysis, P2P terminator can see and nodownload, use the downlink bandwidth are generally in 50K/seconds, the speed where go to?

First call 10000, the operator, single dial-up test downloadspeed 4MBit, normal. Said is the router reason, can not take10 to Taiwan machine. Change a more than 300 ocean router, foundthat the problem remains. Call again 10000, after testing, said4MBit may be too small, so the company to 1300 yuan per yearabout 4MBit civilian bandwidth disabled, replaced by about 2700yuan ADSL6MBit commercial bandwidth, but the network is stillvery slow.

Such a toss about a month later, 10 people every day to complainSuman do not live also dare not to ask the operator to come,because as long as they come to disconnect the router singledial and test also cannot measure what is going to drag all thework.

Later found in a very accidental circumstances, whether or not

to upgrade broadband LAN, always stay uplink speed and in 50KB/seconds, the conclusion is whether it is Internet broadband6MBit or 2MBit or 1MBit, as long as it is ADSL, then only theuplink uplink speed is about 512KBit, the conversion of 64KB/seconds. The problem arises, 6MBit commercial bandwidth only64KB/ seconds uplink speed, the company if there are 10computers, then each computer can be assigned to the uplinkspeed is only about 5KB/ seconds!

Downlink speed, we all should know, the bigger the better, thebig download things can obviously feel fast. But what is therole of uplink speed?For example, we talk about QQ, accept eachother' s message belongs to download, sent his message out tothe uplink, of course, uplink speed to send text messages canoccupy very small and can be neglected, but if the video chat?To see the video image of others is to download, but if the videoimages of their display will occupy the uplink in others insideQQ, uplink 50KB/ seconds can video chat? Reluctantly! Removethe chat QQ, we browse any web page to enter the URL in thebrowser or click the link, the request must pass up to the webwhere the server server can according to user the page requestis delivered to users on the computer, that is to say, as longas the use of the Internet, so all operations are bidirectional,which is different from the TV only Suffer from the need to sendout information. To this problem, the uplink speed a bit if amachine takes up to two, then the request out all the othercomputer LAN will not send, then even if there are no longerany downward speed, because the server cannot receive theuser' s requests!

What will occupy uplink speed? "Requests is very small can be

ignored, but to steal food, online games and other interactiveapplication is very strong occupancy speed, users can not stealfood, do not play online games, but users will download?WatchTV movie mentioned with PPS?For example, the thunder downloadPPS belongs to the P2P software, the software is a share on theInternet but it is the milepost, very ascending speed ofsoftware.

P2P is the abbreviation of English Peer-to-Peer (peer to peer) .It is also called peer to peer". Peer to peer technology is anew network technology that relies on the computing power andbandwidth of the participants in the network rather than on thefew servers on which the dependencies are clustered. P2P orEnglish Point, to, Point (peer to peer) abbreviation. It is adownload term, meaning that your computer will continue to behost while you download it yourself.

Just download, the user opens PPS movies, users will getinformation from other films containing the film and playcomputer, on the machine at the same time, the machine in themovie also will have to download the movie as a source to otherusers need to watch this movie through the uplink transmissionfilm, so there are similar cool dog music. This technology cangreatly reduce the server bandwidth pressure, because the userdoes not need to download resources from the dedicated server(cool dog have a dedicated server, store songs) every user isinthe userresources, enjoy the resources and speed at the sametime, the user computer is a temporary server in resources.This problem is obvious, if I use the thunder and other P2Psoftware to download resources, the thunder will secretly

upload resources for other people to download, because the P2Pnetwork is originally a mutually beneficial technology. But Ican download more than 500K/ seconds, up to less than 500K/seconds. Indeed, the uplink is not up to 500K/ seconds, but at50K/seconds is normal, then the uplink already saturated, evenif the user to download control in 200K/ seconds, the wholenetwork will also paralyzed because the uplink is saturated!