2. So there is some non-TCP traffic. What happens when you load that page in Tor Browser, for example? Does it leak back to your clear Internet connection? Is it simply dropped? This seems like a critical issue.
3. Thanks. Do you know when that was written? To save others clicking the link and finding the applicable section, I'll paste it below. Designing and building your own protocol for Internet transport, compatible with the entire net and performing competitively enough to be usable, sounds like quite a project for a small organization. Note that Google didn't do that; they used UDP for QUIC.
7 Tor Network Compatibility Concerns
Our final area of concern is continued compatibility of the Tor network with future versions of the HTTP proto- col. It is our understanding that there is a desire for future versions of HTTP to move to a UDP transport layer so that reliability, congestion control, and client mobility will be more directly under control of the client user agent.
At present, the Tor Network is only capable of carrying TCP traffic. While it will be possible to support the transit of UDP datagrams using our existing TCP overlay network without significant anonymity risks within a year’s time or sooner, it is unlikely that this level of support will be sufficient to warrant the use of a finely-tuned UDP version of HTTP rather than a TCP variant.
Long term, our goal is to transition the entire Tor network to our own datagram protocol with custom con- gestion and flow control to better support both native datagram transport and end-to-end flow control. However, additional research is still needed to examine the anonymity implications associated with this transition[12]. Our present estimate is that a full network transition to UDP is at least five years away.
We are also concerned that even after a full network transition to a datagram transport, it is likely that the congestion, flow, and reliability control of a UDP version of HTTP may still end up performing poorly over higher-latency overlay networks such as ours.
For these reasons, we are especially interested in ensuring that overlay networks are taken into account in the design of any UDP-based future versions of HTTP, and also prefer to retain the ability to use future HTTP versions over TCP, should the UDP implementations prove sub-optimal for our use case.
I'm not sure if Tor Browser turns off by default, searching found this one ticket which suggest that default flag but maybe it's not implemented out of the box.
[1] https://privacycheck.sec.lrz.de/active/fp_wrtc/fp_webrtc.htm...
It does and it is removed at compile time since that ticket was closed (i.e. that was a build flag not a runtime flag).
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