It's both. A long-running, high-bandwidth stream will cause short-lived, low-bandwidth streams to be squeezed out, because the TCP congestion isn't being manage

It's both. A long-running, high-bandwidth stream will cause short-lived, low-bandwidth streams to be squeezed out, because the TCP congestion isn't being managed properly. The first stream will see relatively good speed but shonky latency, while the later streams will see bad speed as well, when they should share the bandwidth equally.