Hi smart people,
If I have several computers on my home network and I have not set any explicit QoS rules on my router, how is bandwidth allocated? For example, if computer 1 is downloading a torrent at max speed and a second computer starts a download, how is the bandwidth allocation between the two determined? Thanks!
There is no allocation if you haven’t configured any. Whoever can get their shit stuffed in the pipe first wins. From that point, any bottlenecks either FIFO to/from buffers, or if buffers fill up, just start taildropping. TCP (and other transport layer protocols like QUIC) implementations then have a sliding window algorithm that figures out the optimal amount of data to keep in flight at one time based on RTT and any packet loss caused by taildrops along the way.
Note: QUIC is not really a transport layer protocol but uses UDP and builds atop of it.
UDP is hardly a transport layer protocol. It basically adds port numbers and checksum to IP. QUIC is usually described as transport layer since it provides flow/congestion control functionality usually ascribed to transport layer.
Sometimes port numbers is all you need
Sure, hence I said “hardly” rather than “is not.” None of this excludes QUIC from also being transport layer.