Specifications

Best Practices for Virtualizing and Managing Exchange 2013
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Figure 20: PVLAN in Windows Server 2012
Best Practices and Recommendations
VLANS and PVLANS can be a useful mechanism to isolate different Exchange infrastructures—for
instance, a service provider hosting multiple unrelated Exchange infrastructures. For customers
with VLAN constraints, PVLANS enable extra levels of isolation granularity within the same VLAN.
PVLANS can be configured through PowerShell.
Hardware Offloads – Dynamic Virtual Machine Queue
Virtual Machine Queue (VMQ) allows the host’s network adapter to pass DMA packets directly into
individual virtual machine memory stacks. Each virtual machine device buffer is assigned a VMQ, which
avoids needless packet copies and route lookups in the virtual switch. Essentially, VMQ allows the host’s
single network adapter to appear as multiple network adapters to the virtual machines, allowing each
virtual machine its own dedicated network adapter. The result is less data in the host’s buffers and an
overall performance improvement to I/O operations.
VMQ is a hardware virtualization technology for the efficient transfer of network traffic to a virtualized
host operating system. A VMQ-capable network adapter classifies incoming frames to be routed to a
receive queue based on filters that associate the queue with a virtual machine’s virtual network adapter.
These hardware queues may be affinitized to different CPUs, thereby enabling receive scaling on a per-
virtual network adapter basis.
Windows Server 2008 R2 allowed administrators to statically configure the number of processors available
to process interrupts for VMQ. Without VMQ, CPU 0 would run hot with increased network traffic. With