Windows Server Summit | (Software-defined) Networking
Krähe mit HutWindows Server is much more than just a server - it can also be a storage system or a switch, if desired!
The statement is deliberately general. 😏 However, it's true that Windows Server has been capable of providing much more than just classic services like Active Directory, DNS, and WSUS for years.
The rise of virtualization has necessitated the addition of many more features to better manage the new challenges of this technology. One such feature is software-defined networking (details: Software-defined Networking – Wikipedia).
But even when Windows Server is used for traditional virtualization, there are some exciting new features in Windows Server 2025. These will be discussed in more detail below.
Innovations in software-defined networking (SDN)
Network controller with failover clustering
Previously, it was necessary to use dedicated infrastructure VMs to provide the network controller functionality. Now, the network controller can be run as a role within the failover cluster, offering all the familiar advantages, especially in terms of high availability.
A similar approach will be implemented for the VMs currently required to provide Layer 3 and GRE gateway connections.
BGP-less Software Load Balancer
BGP is a valuable protocol for the automatic distribution of network routes. However, it can be difficult to manage and, if misconfigured, can lead to massive outages (as seen with Google in 2019 and Meta in 2021).
For this reason, the requirement to configure BGP has been removed. Nevertheless, BGP can still be used if desired. This feature is not yet available but will be added later.
Health alerts for SDN in the Azure portal
Previously, health alerts could be viewed and responded to via PowerShell or the Windows Admin Center. Soon, alerts will also be viewable and manageable through the Azure portal via an integration with Azure.
This feature is not yet integrated and will be added soon.
Innovations in failover clustering
Network ATC
Network ATC (Architecture Toolchain for Cloud) is a feature for the automated and standardized deployment of network configuration for a Windows failover cluster (or Azure Local). It can be applied either via PowerShell or the Windows Admin Center. This automatically incorporates best practices and avoids (oversights) errors caused by manual configuration. Furthermore, it allows for significant time savings in system deployment.
Network HUD
Windows Server 2025 introduces a new graphical tool called Network HUD, which provides a centralized overview of network problems within the cluster. It is integrated into the Windows Admin Center.
Tag based VM segmentation
This new feature allows network traffic between virtual machines to be regulated directly using security rules. Rules can be created and assigned via the Windows Admin Center.
Accelerated Networking
The name is self-explanatory – this feature helps to intelligently manage network traffic within the cluster, thereby increasing network performance while simultaneously reducing CPU load. This feature requires the use of Azure Arc and Network HUD.
SDN Multisite
Diese Funktion ermöglicht eine native Layer 2- und Layer 3-Konnektivität zwischen mehreren Standorten, wo früher einzelne SDN eingesetzt werden mussten. Darüber ist es nun möglich, VM nahtlos zwischen This feature enables native Layer 2 and Layer 3 connectivity between multiple locations, where previously individual SDNs were required. This makes it possible to seamlessly move VMs between different locations without any changes to connectivity.
Additional information
Official videos:
SDN magic: Windows Server 2025 innovations - Windows Server Summit
Fine-tuned host networking for Windows Server 2025 - Windows Server Summit
Overview of all articles: Windows Server Summit in a nutshell
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