问题
In this old project (from 2002), It says that if you split a file into multiple chunks and then transmit each chunk using a different socket, it will arrive much faster than transmitting it as a whole using one socket. I also remember reading (many years ago) that some download manager also uses this technique. How accurate is this?
回答1:
Given that a single TCP connection with large windows or small RTT can saturate any network link, I don't see what benefit you expect from multiple TCP sessions. Each new piece will begin with slow-start and so have a lower transfer-rate than an established connection would have.
TCP already has code for high-throughput, high-latency connections ("window scale option") and dealing with packet loss. Attempting to improve upon this with parallel connections will generally have a negative effect by having more failure cases and increased packet loss (due to congestion which TCP on a single connection can manage).
Multiple TCP sessions is only beneficial if you're doing simultaneous fetches from different peers and the network bottleneck is outside your local network (like bittorrent) or the server is doing bandwidth limitations per connection (at which point you're optimizing for the server, not TCP or the network).
来源：https://stackoverflow.com/questions/29277554/is-transmitting-a-file-over-multiple-sockets-faster-than-just-using-one-socket