What is the best mtu setting for a wireless router? When we set up the router network, we may find that there is a value called mtu. If it is set well, it can increase the network speed. If it is not set well, it will reduce the network speed. Moreover, it does not have a value. For fixed values, the one that suits you is the best.
What is the fastest network speed set by mtu:
Answer: The fastest mtu is different in different environments.
The larger the MTU, the better, because the larger the MTU, the greater the delay in transmitting a data packet; and the larger the MTU, the greater the probability of bit errors in the data packet.
Of course, the smaller the MTU, the better. As the maximum transmission unit, if it is set too small, the data cannot be transmitted, and the network speed will naturally be slow.
Even for optical fiber lines, the MTU value will be different every time a user dials up (the deviation value of telephone lines, network cables, etc. entering the home may be larger), so the optimal value can only be obtained through actual testing.
Therefore, impatient friends can just keep the default mtu; patient friends can try to lower or increase the value based on the default value, and get the fastest network speed through repeated tests.
Summary: There is no fixed best, only the most reasonable one based on the network environment is the best (the default is enough if you don’t know how to set it. If you want to increase the network speed, you can continue reading the article).
MTU (Maximum Transmission Unit) is the largest transmission unit. Without considering factors such as equipment and lines, of course, the larger the unit, the higher the transmission efficiency.
Because the length of the header and tail of the protocol data unit is a fixed value, the larger the MTU, the longer the effective data carried by a protocol data unit, and the lower the number of data packets required to transmit the same user data.
In Windows systems, the default MTU value is also 1500 bytes, but "different access methods, network operators in different regions, and different routers" have different MTU settings.
For example: When ADSL is connected, the MTU is 1492 bytes. Assume that A needs to transmit 3000 bytes of data to B. If the MTU of each link in the entire transmission process is 1500, then 2 data packets can be transmitted.
However, at this time, the MTU of the ADSL access method is 1492 bytes, and the data packet is split into 3 additional pieces because of this MTU difference (for ease of understanding, the "data packet header" is not taken into consideration for the time being)
Obviously this increases the number of data packets that need to be transmitted, and the process of unpacking and repackaging also wastes time. Additional unpacking can be avoided if a consistent MTU is used from local to network.
Taking Telecom's 4M bandwidth as an example, after changing the MTU value of the operating system to 1492 and then changing the MTU value of the router from 1460 to 1492, the download speed increased from the original 435KB/s to 450KB/s, an increase of 15KB/s. The detection result of Telecom's bandwidth detection tool also increased from 4.09M to 4.19M.
1. When the local MTU value is greater than the network MTU value, the locally transmitted data packets are too large and the network will unpack them before transmitting them. This not only generates additional data packets, but also consumes the time of "unpacking and grouping".
2. When the local MTU value is smaller than the network MTU value, locally transmitted data packets can be transmitted directly, but the upper limit of the data packet transmission size given by the network cannot be fully utilized, and the transmission capability is not fully utilized.
In this way, we know that the so-called reasonable setting of the MTU value is to make the local MTU value consistent with the network MTU value, which can fully exert the transmission performance without allowing data packets to be split.
The next most important thing is to find out what MTU is reasonable for your network environment.
Here's how:
1. Press the Win+R key combination to bring up the "Run" menu, enter "cmd" and press Enter
2. In the "Command Prompt" window that appears, enter "ping -l 1472 -f www.baidu.com" and press Enter
meaning:
ping: initiate a detection request;
-l (lowercase L): limit the detection packet size;
1472: The packet size is 1472 bytes;
-f: Disable the router from splitting packets
www.baidu.com: Set Baidu as the detection target
Linux users:
ping -s 1472www.baidu.com
OS X users:
ping -D -s 1472 www.baidu.com
3. There are two situations at this time:
(1) If a reply is received, it means that the maximum MTU value allowed by your network is 1500 bytes, which is the same as the system default value. You only need to set the MTU value of the router to 1500;
(2) If it is necessary to split the packet but set DF. Or the prompt that Packer needs to be fragmented but DF set. means that the packet size exceeds the MTU size limited by the network. You need to reduce the probe packet size and try again. (In order to screenshot the renderings, I changed the detection package to 1473)
4. Press the "up arrow" to restore the command you just entered, then reduce the packet size to 1467 bytes in steps of 5, and press Enter again to detect.
5. There are also two possibilities at this time:
(1) If there is a return, it means that the data packet is less than the MTU limit, then increase the packet size by 3 and detect again. If there is no return after +3, then reduce the data packet size by 1 as a span for detection.
(2) If there is still no return, continue to reduce the packet size in steps of 5 until there is a return and perform the operation in 5(1).
6. Until you find packet -1, and there is a return, it means that you have detected the accurate packet size allowed by the MTU. (For example, if there is a return when reducing from 1465 to 1464, then the allowed packet size is 1464)
7. However, the value obtained above cannot be set as the MTU of the operating system or router. The packet size you find needs to be added with a 28-byte "packet header" to get the complete packet size.
(For example: the detected packet size is 1464, then add 28 bytes, and the final MTU=1492 bytes)
8. Finally, just set the MTU value in the router and operating system to the result you get.