Software-Defined Networks – Is the Hypervisor Your Next Router?

In the world of virtualized datacenters, many of us have long enjoyed the ability to abstract application workloads from the underlying physical server infrastructure by virtualizing those workloads inside VM's running atop a hypervisor, such as Microsoft Hyper-V or VMware vSphere.  This has proved to be a valuable approach for reducing the cost and complexity of provisioning new application workloads, as many organizations have benefited from improvements in application agility, disaster recovery, ease of migration and consolidated server hardware. Software-Defined Networking (SDN), sometimes referred to as Network Virtualization, expands the level of datacenter abstraction provided by a hypervisor to include not just discrete VM workloads, but entire networks that are virtualized atop an existing physical network infrastructure - extending many of the benefits realized with server virtualization to enterprise network architecture.NetworkVirtualization.GIF


Software-Defined Networks - Extending Virtualization to Network Infrastructure

Why are organizations interested in Network Virtualization?

Organizations are realizing a number of benefits by implementing network virtualization, including:

  • Route network packets at system bus speeds. As organizations increase VM densities on hypervisor host servers, many are seeing high percentages of cross-subnet network traffic occurring between VMs on either the same host or hosts within the same datacenter rack.  By implementing network virtualization, Layer-3 routing between these VMs occurs at system bus speeds, rather than network line rates.
  • Improve network agility. Rather than needing to touch multiple physical network infrastructure devices within VLAN and IP subnet changes, network virtualization changes can be quickly implemented at the software layer, generally performed from a centralized network policy server.
  • Isolate networks and subnets. Particularly in organizations that grow by merger and acquisition and/or organizations that are hosting services on behalf of other customer tenants, network isolation permits the ability to easily accommodate new network and subnet address spaces, even if a portion of these new address spaces overlaps with pre-existing subnets.
  • VM portability across physical network sites. When attempting to move VMs across routed physical network locations, the complexity of IP address changes is commonly involved.  Network virtualization provides the ability to stretch a common virtualized IP address space across multiple physical network sites while retaining the efficiency of a routed Layer-3 physical network.


Get Your Network Ready for a Software-Defined Future!

To learn more about how Microsoft implements Software-Defined Networking in Windows Server 2012 R2 with Hyper-V Network Virtualization (HNV), be sure to leverage the following resources:

See you in the Clouds!

- Keith