About enabling QUIC in android

[Xu Yuanda]

Hi, all
I'm a new learner.
I just learned how to enable QUIC in chrome browser.
May I ask some questions?

After I enabled QUIC, is everything only transmitted by QUIC?
Or QUIC is the first priority to use? (if yes, then when would system switch to udp or even tcp from QUIC)?

BTW, how to enable QUIC in android phone or tablet?
Does "enable QUIC in android" mean enable QUIC for whole system in "settings", or just enable QUIC in android version chrome browser?

Thanks~!

[Robbie Shade]

Hey,

After I enabled QUIC, is everything only transmitted by QUIC?

No - Chrome is careful, and only uses QUIC to talk to domains that it knows speak QUIC. The first time Chrome talks to www.google.com it will connect via TCP. If you look at the HTTP response headers ($ curl -I www.google.com)  you'll see one something like "Alternate-Protocol: 80:quic". This tells Chrome that www.google.com speaks QUIC on port 80. The next time Chrome wants to make such a request, it will try and use QUIC.

 

Or QUIC is the first priority to use? (if yes, then when would system switch to udp or even tcp from QUIC)?

If Chrome has seen an "Alternate-Protocol: 80:quic" header, then the next time you make a request to www.google.com it will "race" a TCP connection and a QUIC connection in parallel. Once the QUIC connection is established then Chrome will prefer QUIC for future requests.

There are always going to be some number of clients which can't connect via QUIC (firewall rules blocking UDP for example). In this case Chrome will detect that QUIC isn't working, and will keep using the TCP connection.

 

BTW, how to enable QUIC in android phone or tablet?

The same way you can enable QUIC in desktop Chrome: go to chrome://flags and look for the Experimental QUIC flag to enable.
 

Does "enable QUIC in android" mean enable QUIC for whole system in "settings", or just enable QUIC in android version chrome browser?

For now the only control you have is in Chrome (via the chrome://flags page I mentioned).

Hope that helps!

Robbie