Windows 2019 Network IS SLOW ON HYPER-V 2019
VM 2019 hosted on Hyper-v 2019 can have serious network performance issue . While windows 2008 to Windows 2012 R2 work just fine and fast !
I have found that fine tuning the TCP settings can resolve the issue, in my case it was CUBIC settings.
CUBIC is an implementation of TCP with an optimized congestion control algorithm for high bandwidth networks with high latency (LFN: long fat networks). CUBIC TCP is implemented and used by default in Linux kernels 2.6. 19 and above, as well as Windows 10.1709 Fall Creators Update, and Windows Server 2016 1709 update
Try to change the setting to CTCP Short for client-to-client protocol :
(run as administrator)
netsh int tcp set supplemental template=internet congestionprovider=CTCP netsh int tcp set supplemental template=internetcustom congestionprovider=CTCP netsh int tcp set supplemental template=Datacenter congestionprovider=DCTCP netsh int tcp set supplemental template=Datacentercustom congestionprovider=DCTCP
To change Back to CUBIC
netsh int tcp set supplemental template=internet congestionprovider=CUBIC netsh int tcp set supplemental template=internetcustom congestionprovider=CUBIC netsh int tcp set supplemental template=Datacenter congestionprovider=CUBIC netsh int tcp set supplemental template=Datacentercustom congestionprovider=CUBIC