[German]Microsoft has announced the general availability of LEDBAT for the upcoming Windows Server 2019 version. But LEDBAT can already be used in Windows 10 and Windows Server 2016 optional in an experimental mode.
Some background: Optimizing TCP stack
In July 2016, Microsoft announced five new features (some on an experimental basis) for the TCP stack of Windows Server 2016 and Windows 10 Anniversary Update (V1607). The Register has discussed the following new features in this blog post.
- TCP Fast Open (TFO) for zero RTT TCP connection setup. IETF RFC 7413
- Initial Congestion Window 10 (ICW10) by default for faster TCP slow start
- TCP Recent ACKnowledgment (RACK) for better loss recovery (experimental IETF draft)
- Tail Loss Probe (TLP) for better Retransmit TimeOut response (experimental IETF draft)
- TCP LEDBAT for background connections IETF RFC 6817
Microsoft argued at the time that the changes were necessary “to reduce latency (of Internet connections via TCP), improve reliability and promote better network citizenship”.
Especially #5 TCP LEDBAT is interesting. According to Wikipedia, LEDBAT (Low Extra Delay Background Transport) offers the ability to quickly transfer data over the Internet without clogging the network.
LEDBAT was developed by Stanislav Shalunov and is used by Apple for software updates and by BitTorrent for most of its transmissions. It is estimated that 13-20% of Internet traffic is handled by LEDBAT. LEDBAT is a delay-based overload control algorithm that utilizes the entire available bandwidth while limiting the increase in delay. It does this by measuring the one-sided delay and using changes in the measurements to limit the overload caused by the LEDBAT flow itself on the network.
Full support for Microsoft LEDBAT in Server 2019
Now Microsoft has declared LEDBAT as GA (General Availability) for Windows Server 2019. This is reported by The Register in this article. Microsoft employee Daniel Havey has probably contacted The Register and told the editors that LEDBAT has reached full support for Windows Server 2019 (this OS version is still in the preview phase). At the same time, Havey published this blog posts with more details using LEDBAT under Windows Server 2019. The article mentions also how to use LEDBAT in SCCM.