Unveil the truce of real speed
Using ADSL users often, do you know the real speed of ADSL? With this question, we will start the problem step by step.
Many users reflect, the ADSL download rate does not reach the nominal 512K, after the brain passes the ADSL access network, there will be a download rate indicator when downloaded, and the download rate displayed above is generally 50 kbyte / s! This is actually a misunderstanding caused by a conversion relationship.
1,512k ADSL mean?
512K = 512kbps = 512k bits / s = 64K bytes / s
I think this will have no problem.
What does 2,64k bytes / s mean?
The true meaning of this 64K is "the biggest download bandwidth that individual users can enjoy"
So what does this mean? I don't know if there is anyone who has noticed the application form for Telecom ADSL installation. The above bandwidth project writes "no higher than 512K", "no higher than 8m", etc., that is, Say that we can have up to 64k-have-bandwidth in normal cases.
Note that it is "not higher than", then it means many times our proprietary bandwidth may be less than 64K, is it why?
In fact, China Telecom's ADSL is running on the ATM, and the ATM to the chinanet edge router bandwidth is 155m, and each edge router can connect to 3000 users. If these users are simultaneously online, then each user is only 50k bit / s bandwidth, That is, 7k bytes / s, plus the router attenuation, then eventually only the speed of ordinary Modem.
Of course, the above is only imaginary. After all, 3,000 people are almost impossible over one edge router. Telecom does not make the router full-load connection and make the speed fall so.
However, 64K is the highest proprietary bandwidth is unquestionable.
3, why can my 512K ADSL often reach the speed of 100k or even 200K?
We figured out that 64K is the largest exertion wide, but not equal to the maximum bandwidth. In fact, the actual approximately 8Mbps is already allocated at the ADSL dial, which is 1M Bytes / S download bandwidth, but telecommunications limits our proprietary The bandwidth is up to 64K, then when the router is connected to the user, we can get a part of the shared bandwidth that exceeds the proprietary bandwidth (obviously telecom is not necessary to idle these bandwidth), of course, the 512K rate ADSL will never achieve shared bandwidth The download speed of 1m / s, because there is always a lot of people in the same time after all, and Telecom has some balanced load mechanism.
4, the impact of ADSL upload speed on download
TCP / IP regulations, each package needs to have an ACKNOWLEDGE message, that is, the transferred information, you need a message reply that receives the information, can determine whether to re-transmit the lost data.
A part of the uplink is used to lose @ some Acknowledge (confirmed) Y material, when the uplink load is too large, it will affect the speed of the Acknowledge data, and then affect the download speed. This is especially obvious that the asymmetric digital loop is also the connection of the ADSL's uplink bandwidth far less than the download bandwidth.
There is a test prove that when the upload is fully loaded, the download speed is changed to 40% of the ideal speed. This can explain why many friends are slightly limited to the BT download, but can get a bigger download speed.
In this case, we can't ask all people to be unmarried, because this is very unrealistic for ADSL users, and is not scientific. The appropriate speed limit is correct.
5, the speed of ADSL gradually decreases as the connection time is extended.
The highest theoretical 8Mbps download bandwidth will be established when I say ADSL and then dial, this bandwidth will never change! However, due to the noise detection mechanism of ADSL If the line situation is not good, the connection established is clearly impossible to achieve the theoretical value, it may eventually be 5Mbps, this bandwidth will not change. So why said the speed of ADSL is getting slower and slower?
This is because even if the user does not close the power supply of the modem, sometimes the ADSL link will be interrupted at any time. For example, in the case where the communication status is deteriorated due to the increase in noise, there is frequent errors. After the link is interrupted, you will immediately re-debug and re-determine the link. However, if the noise of the link interrupt still exists at this time, (this is generally a relatively large) re-linking speed will be lower than the original. Since the link speed determined in debug is also fixed, even after the noise disappears, the link speed will not increase. The longer the ADSL modem usage time, the higher the possibility of this situation, so the connection speed is getting slower.
At this time, if the user restarts the modem, the link will reiterate and the speed may result in an increase. This common sense can be used as a process countermeasure after the link speed is reduced.
Of course, these situations are only discussed according to the ADSL connection itself, and the actual situation also includes Internet conditions, the response of the website itself, etc.
Understand the above knowledge, you may suddenly be clear. It turns out that 512K is not 512KB, only 64kb, 呜 ~~~ You can't reach 512KB download speed per second.
True to achieve ADSL's high speed
The most important thing to pay for the ADSL speed is that the user host has to reach a certain configuration to ensure the speed of ADSL access on the hardware. As the saying goes, "There is no diamond, do not live in porcelain". If the personal computer has high processing performance, you can quickly run the web browser and email software and increase Internet speed. If the 1Mbps of ADSL is installed, but the personal computer can only load Windows95 or 98, of course, the speed is slow. Especially in memory If only 64MB or 128MB is only 64MB or 128MB, broadband is like a hero. If you update your computer, the operating system can use WindowsXP, the natural broadband access is increased. In addition, WindowsXP requires more memory than the original Windows system, and there is a minimum of 256MB of memory. If there is no ability to update your personal computer, then increase the memory, as long as the memory can feel the speed increase. In addition, the ADSL modem used by broadband access also supports high speeds to ensure access speed.
There are also some ways to maintain the ADSL maintenance on the hardware, such as shortening the telephone line between the telephone socket and the ADSL modem, and minimizing line loss, the specific operation can shorten the distance between the telephone socket and the ADSL modem, the long connection modem and The network cable of a personal computer does not reduce the speed. There is also an office equipment (including personal computer) or TV, refrigerator, etc. in the ADSL modem, etc., mobile phones will cause interference to the modem.
People who are familiar with the computer should know that the performance of a personal computer depends not only on its hardware foundation, but also software optimization of the computer in the later stage can also become the power of online flying. On the one hand, the performance of the system can improve, the vacancy rate of the CPU, the usage rate of the memory, the debris cleaning of the hard disk can be improved by software. On the other hand, when the broadband access is connected, some specialized software can be optimized, and some network coupling settings are randomly adjusted to achieve the best connection effect.
