Hyper-V VM-FEX Standalone Video Configuration Guide



A virtualized server implementation consists of one or more VMs running as 'guests' on a single physical server. The guest VMs are hosted and managed by a software layer called the hypervisor or virtual machine manager (VMM). The hypervisor typically presents a virtual network interface to each VM and performs Layer 2 switching of traffic from a VM to other local VMs or to a physical interface to the external network. Working with a Cisco virtual interface card (VIC) adapter, Cisco Virtual Machine Fabric Extender (VM-FEX)bypasses software-based switching of VM traffic by the hypervisor in favor of external hardware-based switching in the fabric interconnect. This method results in a reduced load on the server CPU, faster switching,and the ability to apply a rich set of network management features to local and remote traffic. VM-FEX extends the (prestandard) IEEE 802.1Qbh port extender architecture to the VMs, providing each VM interface with a virtual Peripheral Component Interconnect Express (PCIe) device and a virtual port ona switch. This solution allows precise rate limiting and quality of service (QoS) guarantees on the VM interface.


Infrastructure Requirements


  • The host must be managed by Cisco UCS Manager Release 2.1 or later.
  • The host operating system must be an edition of Windows Server 2012 or later that includes Hyper-V support. For more information about installing Microsoft Hyper-V, see the Microsoft Windows Server documentation.
  • In the host BIOS Processor settings, you must enable Virtualization Technology (VT) and Direct Cache Access.
  • In the host BIOS Intel Directed I/O settings, you must enable VT For Directed I/O and Interrupt Remap.
  • For more information about configuring UCS server BIOS settings, see the Cisco UCS Manager GUI Configuration Guide.
  • HTTPS communication must be enabled on the Cisco UCS Manager. For more information about enabling HTTPS communication, see the Cisco UCS Manager GUI Configuration Guide.
  • One or more Cisco VIC adapters must be installed in the host. For more information about installing a Cisco VIC adapter, see the Cisco UCS 5108 Server Chassis Hardware Installation Guide.
  • An SR-IOV PF cannot be used as an iSCSI vNIC. An existing iSCSI vNIC cannot be defined as a PF.


VM-FEX Mode of Operations





Hypervisor Bypass with SR-IOV

Minimum Hypervisor Version

Windows 2012

Windows 2012

Minmum ENIC Driver Version

UCSM 2.1(1a)

UCSM 2.1(1a)
Minimum VIC Firmware Version

UCSM 2.1(1a)

UCSM 2.1(1a)

VM-FEX Tool Pleaese refer to attachment Please refer to attachment

VMotion / Live Migration

Support Guest OSAny OS support by Hyper-V

Windows 2012 only


VM-FEX Scalability


UCSM Configuration Limit 2.1 Release -http://www.cisco.com/en/US/docs/unified_computing/ucs/sw/configuration_limits/2.1/b_UCS_Configuration_Limits_2_1.html



Cisco UCS 6100 / 6200 Series



Half-Width Blade with Single VIC


Full-Width Blade with Dual VIC

ESX 4.0 – 4.1 (DirectPath I/O)

56 (54 vNIC + 2 vHBA)

56 (54 vNIC + 2 vHBA)

ESXi 5.0 – 5.1 (DirectPath I/O)

116 (114 vNIC + 2 vHBA)

116 (114 vNIC + 2 vHBA)*

Windows 2012 (SR-IOV)

116 (114 vNIC + 2 vHBA)

232 (228 vNIC + 4 vHBA)

KVM 6.1 – 6.3 (SR-IOV)

116 (114 vNIC + 2 vHBA)

232 (228 vNIC + 4 vHBA)


* Additional VIC will NOT increase the total VIF count due to OS limitation

* Multiple VICs are Supported for full width blade and B200M3


Video Configuration Demo Topology


Hyper-V VM-FEX Configuration Workflow

hyper-V VMFEX walkthrough.png

Reference Documentation

UCSM Hyper-V VM-FEX GUI Configuratoin Guide



UCSM Hyper-V VM-FEX CLI Configuratoin Guide



Hyper-V VM-FEX Configuration Example - TAC



Cisco-Live-BRKCOM-2005-Virtual Machine Fabric Extension (VM-FEX)-2013

VM-FEX Configuration & Best Practice for Multiple Hypervisor


Please refer to the attachmenta


Cisco VM-FEX Performance Testing verus VMware vSwitch



External (Light Reading) VM-FEX Peroformance Testing verus VMware vSwitch



VM-FEX Performance Testing with SAP



VM-FEX Performance Testing with Microsoft SharePoint 2010



VM-FEX Performance Testing with Microsoft SQL Server 2012



VM-FEX Performance Testing with Citrix Xenapp 6.5



Microsoft Private Cloud Fast Track 3.0 with VM-FEX