For users who often use ADSL, do you know the real speed of ADSL? With this question, we will unfold the question step by step.
Many users have reported that the ADSL download rate does not reach the nominal 5 12K. After connecting to the network through ADSL, a download rate indicator will appear when downloading. The download rate shown above is generally around 50KByte/s! This is actually a misunderstanding caused by unclear conversion relationships.
1. What does 512KADSL mean?
512K=512Kbps=512Kbits/s=64Kbytes/s
I think there should be no problem with this conversion.
2. What does 64Kbytes/s mean?
What this 64K really means is "the maximum download bandwidth that individual users can enjoy"
So what does this mean? I wonder if anyone has noticed the application form for Telecom ADSL installation. The bandwidth items above are all written as no higher than 512K", "no higher than 8M", etc. That is to say, under normal circumstances, we can have a maximum of no higher than 64K of proprietary bandwidth. Note that it is "no higher than", so that in many cases our proprietary bandwidth may be less than 64K, so why?
In fact, China Telecom's ADSL runs on ATM. The bandwidth of ATM to chinanet edge routers is 155M. Each edge router can connect to 3,000 users. If these users are online at the same time, each user actually has only 50kbit/s bandwidth, that is, 7Kbytes/s. With router attenuation, then in the end, it may only have the speed of ordinary modem.
Of course, the above is just an imaginary situation. After all, it is almost impossible for 3,000 people to connect to an edge router at the same time. Telecom will not allow the router to be connected at full load, causing the speed to drop so much.
However, there is no doubt that 64K is the highest proprietary bandwidth.
3. Then why can my 512KADSL often reach download speeds of 100K or even above 200K?
We figured out that 64K is the maximum proprietary bandwidth, but it does not equal the maximum bandwidth. In fact, when ADSL dials, the actual download bandwidth is about 8Mbps, that is, 1Mbytes/s. However, Telecom limits our proprietary bandwidth to up to 64K. So when there are fewer users connected to the router, we can get a part of the shared bandwidth that exceeds the proprietary bandwidth (obviously, there is no need for Telecom to let these bandwidths idle). Of course, ADSL with a 512K rate will never reach a download speed of 1M/s by occupying shared bandwidth, because after all, there are still many people surfing the Internet at the same time, and Telecom must have some mechanism to balance load.
4. The impact of ADSL upload speed on download
TCP/IP stipulates that every packet needs to be back-passed by acknowledge messages, that is, the transmitted information needs to have a message reply received by the information to determine the subsequent transmission speed and whether to re-transmit the lost information.
Part of the uplink bandwidth is used to transmit these acknowledge (confirmation) data. When the uplink load is too large, it will affect the transmission speed of the acknowledge data and thus affect the download speed. This has a particularly significant impact on connections such as asymmetric digital loops, that is, ADSL, where the uplink bandwidth is much smaller than the download bandwidth.
Experiments have proved that when the upload is fully loaded, the download speed becomes 40% of the ideal speed, which can explain why many friends can obtain a larger download speed when using BT to download it with a slight speed limit.
Since this is the case, we cannot require everyone to have no speed limit, because it is very unrealistic and unscientific for ADSL users. Proper speed limit is correct.
5. The speed of ADSL gradually decreases with the increase of connection time.
As mentioned earlier, when ADSL dials again, it will establish a maximum theoretical download bandwidth of 8Mbps, which will never change! However, in fact, because ADSL's noise detection mechanism is not good, the connection established at the beginning will obviously not reach the theoretical value, and it may end up with 5Mbps, and the bandwidth will not change.
Then why is ADSL slower and slower?
This is because even if the user does not turn off the modem's power, sometimes the ADSL link will be interrupted at any time. For example, when the communication state deteriorates due to the increase in noise and frequent errors occur. After the link is interrupted, it will be debugged immediately and the link will be re-identified. However, if the noise that causes the link to be interrupted still exists at this time, (this is generally relatively large) the speed after relinking will be lower than before. Since the link speed determined during debugging is also fixed, the link speed will not increase even after the noise disappears later. The longer the ADSL modem is used, the higher the chance that this will happen, so the connection speed is getting slower and slower.
At this time, if the user restarts the modem, the connection will be re-established and the speed may be increased. This common sense can be used as a countermeasure after link speed is reduced.
Of course, the above situations are only discussed based on the ADSL connection itself, and the actual situation also includes the Internet situation, the response of the website itself, etc.
After understanding the above knowledge, you may suddenly feel enlightened. It turns out that 512K is not 512KB, it is only 64KB. Woo~~~ You can't reach the download speed of 512KB per second.
Really realize high-speed ADSL
The most important thing to pay attention to when solving ADSL speed is that the user host must achieve a certain configuration in order to ensure the speed of ADSL access on the hardware. As the saying goes, "If there is no diamond, you won't take care of porcelain work." If the processing performance of a personal computer is high, you can quickly run a web browser and email software to improve the Internet speed. If you have 1Mbps ADSL installed but your personal computer can only install Windows 95 or 98, of course you will feel that the speed is slow. Especially if the memory is only 64MB or 128MB, broadband is like a hero who has no use. If the operating system is updated and the operating system can use Windows XP, the speed of broadband access will naturally be increased. In addition, Windows XP requires more memory than the original Windows system, and it is recommended to have at least 256MB of memory. If you do not have the ability to update your personal computer, then increase the memory. As long as you increase the memory, you can feel the speed increase. In addition, the ADSL modem used for broadband access must also support high speed to ensure access speed.
There are also some methods for maintaining ADSL on hardware, such as shortening the telephone line between the telephone socket and the ADSL modem as much as possible, which can minimize the line loss. The specific method can shorten the distance between the telephone socket and the ADSL modem, and lengthen the network cable connecting the modem to the personal computer, so that the speed will not be reduced. Also, do not place office equipment (including personal computers) that emit electromagnetic waves near the ADSL modem, or home appliances, and mobile phones such as TVs, refrigerators, etc., which will cause interference to the modem.
Anyone who is familiar with computers should know that the performance of a personal computer not only depends on its own hardware foundation, but later software optimization of the computer can also become the driving force for the Internet to fly. On the one hand, the performance of the system itself can be improved through more "flooded" system optimization software now. The CPU vacancy rate, memory usage rate, hard disk fragment cleaning, etc. can all be improved through the power of the software. On the other hand, when broadband accessing the connected network, some special software can also be used to optimize and randomly adjust some network connection settings to achieve the best connection effect.
Many users have reported that the ADSL download rate does not reach the nominal 5 12K. After connecting to the network through ADSL, a download rate indicator will appear when downloading. The download rate shown above is generally around 50KByte/s! This is actually a misunderstanding caused by unclear conversion relationships.
1. What does 512KADSL mean?
512K=512Kbps=512Kbits/s=64Kbytes/s
I think there should be no problem with this conversion.
2. What does 64Kbytes/s mean?
What this 64K really means is "the maximum download bandwidth that individual users can enjoy"
So what does this mean? I wonder if anyone has noticed the application form for Telecom ADSL installation. The bandwidth items above are all written as no higher than 512K", "no higher than 8M", etc. That is to say, under normal circumstances, we can have a maximum of no higher than 64K of proprietary bandwidth. Note that it is "no higher than", so that in many cases our proprietary bandwidth may be less than 64K, so why?
In fact, China Telecom's ADSL runs on ATM. The bandwidth of ATM to chinanet edge routers is 155M. Each edge router can connect to 3,000 users. If these users are online at the same time, each user actually has only 50kbit/s bandwidth, that is, 7Kbytes/s. With router attenuation, then in the end, it may only have the speed of ordinary modem.
Of course, the above is just an imaginary situation. After all, it is almost impossible for 3,000 people to connect to an edge router at the same time. Telecom will not allow the router to be connected at full load, causing the speed to drop so much.
However, there is no doubt that 64K is the highest proprietary bandwidth.
3. Then why can my 512KADSL often reach download speeds of 100K or even above 200K?
We figured out that 64K is the maximum proprietary bandwidth, but it does not equal the maximum bandwidth. In fact, when ADSL dials, the actual download bandwidth is about 8Mbps, that is, 1Mbytes/s. However, Telecom limits our proprietary bandwidth to up to 64K. So when there are fewer users connected to the router, we can get a part of the shared bandwidth that exceeds the proprietary bandwidth (obviously, there is no need for Telecom to let these bandwidths idle). Of course, ADSL with a 512K rate will never reach a download speed of 1M/s by occupying shared bandwidth, because after all, there are still many people surfing the Internet at the same time, and Telecom must have some mechanism to balance load.
4. The impact of ADSL upload speed on download
TCP/IP stipulates that every packet needs to be back-passed by acknowledge messages, that is, the transmitted information needs to have a message reply received by the information to determine the subsequent transmission speed and whether to re-transmit the lost information.
Part of the uplink bandwidth is used to transmit these acknowledge (confirmation) data. When the uplink load is too large, it will affect the transmission speed of the acknowledge data and thus affect the download speed. This has a particularly significant impact on connections such as asymmetric digital loops, that is, ADSL, where the uplink bandwidth is much smaller than the download bandwidth.
Experiments have proved that when the upload is fully loaded, the download speed becomes 40% of the ideal speed, which can explain why many friends can obtain a larger download speed when using BT to download it with a slight speed limit.
Since this is the case, we cannot require everyone to have no speed limit, because it is very unrealistic and unscientific for ADSL users. Proper speed limit is correct.
5. The speed of ADSL gradually decreases with the increase of connection time.
As mentioned earlier, when ADSL dials again, it will establish a maximum theoretical download bandwidth of 8Mbps, which will never change! However, in fact, because ADSL's noise detection mechanism is not good, the connection established at the beginning will obviously not reach the theoretical value, and it may end up with 5Mbps, and the bandwidth will not change.
Then why is ADSL slower and slower?
This is because even if the user does not turn off the modem's power, sometimes the ADSL link will be interrupted at any time. For example, when the communication state deteriorates due to the increase in noise and frequent errors occur. After the link is interrupted, it will be debugged immediately and the link will be re-identified. However, if the noise that causes the link to be interrupted still exists at this time, (this is generally relatively large) the speed after relinking will be lower than before. Since the link speed determined during debugging is also fixed, the link speed will not increase even after the noise disappears later. The longer the ADSL modem is used, the higher the chance that this will happen, so the connection speed is getting slower and slower.
At this time, if the user restarts the modem, the connection will be re-established and the speed may be increased. This common sense can be used as a countermeasure after link speed is reduced.
Of course, the above situations are only discussed based on the ADSL connection itself, and the actual situation also includes the Internet situation, the response of the website itself, etc.
After understanding the above knowledge, you may suddenly feel enlightened. It turns out that 512K is not 512KB, it is only 64KB. Woo~~~ You can't reach the download speed of 512KB per second.
Really realize high-speed ADSL
The most important thing to pay attention to when solving ADSL speed is that the user host must achieve a certain configuration in order to ensure the speed of ADSL access on the hardware. As the saying goes, "If there is no diamond, you won't take care of porcelain work." If the processing performance of a personal computer is high, you can quickly run a web browser and email software to improve the Internet speed. If you have 1Mbps ADSL installed but your personal computer can only install Windows 95 or 98, of course you will feel that the speed is slow. Especially if the memory is only 64MB or 128MB, broadband is like a hero who has no use. If the operating system is updated and the operating system can use Windows XP, the speed of broadband access will naturally be increased. In addition, Windows XP requires more memory than the original Windows system, and it is recommended to have at least 256MB of memory. If you do not have the ability to update your personal computer, then increase the memory. As long as you increase the memory, you can feel the speed increase. In addition, the ADSL modem used for broadband access must also support high speed to ensure access speed.
There are also some methods for maintaining ADSL on hardware, such as shortening the telephone line between the telephone socket and the ADSL modem as much as possible, which can minimize the line loss. The specific method can shorten the distance between the telephone socket and the ADSL modem, and lengthen the network cable connecting the modem to the personal computer, so that the speed will not be reduced. Also, do not place office equipment (including personal computers) that emit electromagnetic waves near the ADSL modem, or home appliances, and mobile phones such as TVs, refrigerators, etc., which will cause interference to the modem.
Anyone who is familiar with computers should know that the performance of a personal computer not only depends on its own hardware foundation, but later software optimization of the computer can also become the driving force for the Internet to fly. On the one hand, the performance of the system itself can be improved through more "flooded" system optimization software now. The CPU vacancy rate, memory usage rate, hard disk fragment cleaning, etc. can all be improved through the power of the software. On the other hand, when broadband accessing the connected network, some special software can also be used to optimize and randomly adjust some network connection settings to achieve the best connection effect.