A new build of the Windows Server vNext Long-Term Servicing Channel (LTSC) release is available for testing.

Announcing Windows Server vNext Preview Build 20201

Hello Windows Insiders! Today we are excited to release a new build of the Windows Server vNext Long-Term Servicing Channel (LTSC) release that contains both the Desktop Experience and Server Core installation options for Datacenter and Standard edition.

What’s New

CoreNet: Data Path and Transports

MsQuic – an open source implementation of the IETF QUIC transport protocol powers both HTTP/3 web processing and SMB file transfers.

UDP performance improvements — UDP is becoming a very popular protocol carrying more and more networking traffic. With the QUIC protocol built on top of UDP and the increasing popularity of RTP and custom (UDP) streaming and gaming protocols it is time to bring the performance of UDP to a level on par with TCP. In Server vNext we include the game changing UDP Segmentation Offload (USO). USO moves most of the work required to send UDP packets from the CPU to the NIC’s specialized hardware. Complimenting USO in Server vNext we include UDP Receive Side Coalescing (UDP RSC) which coalesces packets and reduces CPU usage for UDP processing. To go along with these two new enhancements, we have made hundreds of improvements to the UDP data path both transmit and receive.

TCP performance improvements — Server vNext uses TCP HyStart++ to reduce packet loss during connection start up (especially in high speed networks) and SendTracker + RACK to reduce Retransmit TimeOuts (RTO). These features are enabled in the transport stack by default and provide a smoother network data flow with better performance at high speeds.

PktMon support in TCPIP — The cross-component network diagnostics tool for Windows now has TCPIP support providing visibility into the networking stack. PktMon can be used for packet capture, packet drop detection, packet filtering and counting for virtualization scenarios, like container networking and SDN.

Announcing Windows Server vNext Preview Build 20201