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playground:faq:better_wireless_throughput_with_openwrt_than_with_oem_firmware [2018/07/08 18:34] (current)
tmomas created
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 +====== Better wireless throughput with OpenWrt than with OEM firmware? ======
 +
 +**Issue:** Wireless throughput with OEM firmware is below my expectations. Will OpenWrt give me better wireless throughput than with OEM firmware?
 +
 +
 +**Explanation:​**
 +Whereas [[wp>​throughput]] on Ethernet-connection could depend on limited CPU power alone, the throughput on a 802.11-connection depends on many more parameters.
 +  - first of all there is the **//<​color yellow>​theoretical</​color>//​ maximum throughput** under optimal conditions, and the values the [[wp>​Ferengi]] advertise their merchandise((Remember the //Rule of Acquisition No. 239//: "Never be afraid to mislabel a product."​)) is the TMT...
 +    - e.g. the TMT is 100MBit/s for [[wp>​Fast Ethernet]]
 +    - e.g. the TMT is 54MBit/s or 300MBit/s or even 450MBit/s for 802.11-hardware
 +  - then there is the payload throughput
 +    - e.g. 97,28% the TMT for Fast Ethernet (cf. ->​[[wp>​Ethernet_frame#​Maximum_throughput|Protocol Efficiency]])
 +    - e.g. FIXME % the TMT for 802.11, without techniques such as [[wp>​frame aggregation]] ​ (search for "IEEE 802.11 MAC Frames"​)
 +  - then there are a whole bunch of **interference factors**, who all lessen this value considerably.
 +
 +Please read [[docs:​guide-developer:​networking:​datagram.structures]] to make sure, we all talk about the same things. Thank you ;-)
 +
 +| {{:​meta:​icons:​tango:​dialog-information.png?​nolink}} | When you measure the throughput of an action (the copy of a file), what exactly are you measuring? The throughput of the payload, or the throughput of payload + overhead? For Ethernet the difference can be small, but for DSL-PPPoE or 802.11 the difference is bigger. So it's always good to know, what actually you are measuring. A good manual will tell you what a software is precisely doing. ​ |
 +
 +:!: Whether an OEM firmware gives you better throughput then OpenWrt is a matter of SOFTWARE (since both run on the same hardware...). So ask yourself, what Operating System is used for the OEM firmware. Probably some sort of GNU/Linux. In Linux, drivers are part of Kernel. In OpenWrt we use quite new Kernel with even newer wireless drivers. So it IS possible, that OEM firmware gives you better throughput, but since both, OEM and OpenWrt, use Linux kernel and Linux drivers, well, ...
 +  * [[https://​lwn.net/​Articles/​454390/​|LWN:​ Network transmit queue limits]]
 +
 +
 +{{tag>​faq wireless wireless_throughput}}
  
playground/faq/better_wireless_throughput_with_openwrt_than_with_oem_firmware.txt · Last modified: 2018/07/08 18:34 by tmomas