A new option in Microsoft Edge in Windows 10 is the ability to enable TCP Fast Open. TCP Fast Open (TFO) is a specification to open successive TCP connections faster between clients and servers using a crytographic cookie which stores authentication details to reduce the round-trip delay and lower the latency in the start of data transmission. When enabled, it can improve network performance of the browser. Here is how to enable it.
When a "Fast Open capable" client connects to a server for the first time, it inserts a special encrypted cookie in the initial TCP connection message, prompting the server to send back a valid cookie in response. When this happens, it indicates that both the client and the server support the TCP Fast Open procedure and the server can start sending data to the client before the 3-way handshake completes. Pages you open with the TCP Fast Open option enabled will open faster.
To enable TCP Fast Open in Microsoft Edge, you need to do the following.
- Type about:flags in address bar of Edge.
- The following page will appear:
Scroll it down until you see the Networking section:
- Tick the checkbox "Enable TCP Fast Open".
Now, re-open the browser. You are done. Depending on how many sites you visit supporting the TCP Fast Open feature, you might notice benefits of having this feature enabled.