3 ms·
TCP congestion window scaling is not negligible, especially not in high-latency environments. The initcwnd is usually 14,6kb(10x MSS of 1460 byte in common DSL
by littlecranky67 7y ago
TCP congestion window scaling is not negligible, especially not in high-latency environments. The initcwnd is usually 14,6kb(10x MSS of 1460 byte in common DSL setups), meaning a server can only send those 14,6 kb until the connection is stalled and an ACK is received (=1x roundtrip). Google realized this and tried to get a kernel patch into Linux where the browser (or any userspace program) can manipulate the initcwnd. The patch got rejected, and thats basically why they came up with QUIC: To be able to build on UDP and implement congestion control and other stuff TCP usually does (ordering, checksumming etc) in userspace.