3 ms·

Does it not use UDP?

• mobilio 6y ago
  It uses UDP because simply can't change all TCP infrastructure worldwide. Example - i'm still using on some place router Linksys WRT54GL with kernel 2.4 that is almost 15 years old. Because device still works and there was low network requirements.
  • xxpor 6y ago
    Sure, I totally get that. But my point is UDP doesn't have any underlying congestion control you have to fight.
• Matthias247 6y ago
  Right - it does. My point was that Quic still has 2 layers which determine the amount of data that is sent to peers. On the lower level, there is a congestion controller - which can be like Cubic, New Reno, BBR, etc. This part does not know anything about Quic streams yet. On a higher level you have the Quic streams, which carry user data. These are subject to flow control windows, and there also exists a shared per-connection window. Depending on the implementation the layers might not be very much aware of each other, which can also lead to imperfect utilization. That said the situation is obviously still different than with TCP, since the congestion controller does not limit the amount of user data but packets in general (which includes retransmits, etc). So the outcomes will certainly be different than what we observe with HTTP/2.