Hi,
Two machines over a high bandwidth, low latency network. One is Ubuntu Desktop, the other is Windows 10. There's an iPerf server on the other end. The network is a 1gbps leased line. Same version of iPerf on both clients and server.
When I run Ubuntu TCP iPerf, I receive ~900 Mbps which is what I'd expect. However when I run a Windows TCP iPerf, I get around ~50-100Mbps. Weird right?
I directly connected this Ubuntu and Windows laptop together, and ran the test again: 1Gbps between the two, so I know both laptops are capable of achieving the speed.
I wiresharked the test with the packet captures side by side: the packets are *identical* other than the Window Size Value, and it differs as follows:
Windows - Window Size = 53248, Window size scaling factor = 4, Calculated Window Size = 212992.
Ubuntu - Window Size = 229, Window size scaling factor = 128, Calculated Window Size = 29312.
When disabling TCP Window Scaling on either machine, performance degrades.
Really confused, no idea and have never seen anything like this. Anyone got any ideas?
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