Comment by patmorgan23
20 hours ago
I mean isn't a single TCP connections throughput limited by the latency? Which is why in high(er) latency WAN links you generally want to open multiple connections for large file transfers.
20 hours ago
I mean isn't a single TCP connections throughput limited by the latency? Which is why in high(er) latency WAN links you generally want to open multiple connections for large file transfers.
Only simpler transfer protocols, like TFTP, are limited by latency.
The whole reason for the existence of TCP is to overcome the throughput limit determined by latency. On a network with negligible latency there is no need for TCP (you could just send each packet only after the previous is acknowledged, but the higher is the throughput of your network interface, the less likely is that the latency can be negligible).
However, for latency to not matter, the TCP windows must be large enough (i.e. the amount of data that is sent before an acknowledge is received, which happens after a delay caused by latency).
I use Windows very rarely today, so I do not know its current status, but until the Windows XP days it was very frequent for Windows computers to have very small default TCP window sizes, which caused low throughput on high-latency networks, so on such networks they had to be reconfigured.
On high-latency networks, opening multiple connections is just a workaround for not having appropriate network settings. However, even when your own computer is configured optimally, opening multiple connections can be a workaround against various kinds of throttling implemented either by some intermediate ISP or by the destination server, though nowadays most rate limits are applied globally, to all connections from the same IP address, in order to make this workaround ineffective.