Tradeoff between Cisco VM-FEX and Nexus 1000v

Today’s Network in Virtualization World is Changing

  • §Desire for VM-level access-layer policy & monitoring
  • §Virtualization is driving higher link utilization
  • §More demanding role of network (i.e. DRS)
  • §Current approaches lead to inconsistent network policies

Transparency in the Eye of the Beholder, with virtualization, VMs have a transparent view of their resources. But its difficult to monitor & apply network and storage policy back to virtual machines. Scaling globally depends on maintaining transparency while also providing operational consistency.

So what is the vision:

• VMotion may move VMs across physical ports—policy must follow
• Impossible to view or apply policy to locally switched traffic
• Cannot correlate traffic on physical links—from multiple VMs

So how do we achieve this? Yeah we have VN-Link.


What is VN-Link


  • VN-Link, or Virtual Network Link, is a term which describes a new set of features and capabilities that enable VM interfaces to be individually identified, configured, monitored, migrated and diagnosed.
  • The term literally refers to a VM specific link that is created between the VM and Cisco switch.  It is the logical equivalent & combination of a NIC, a Cisco switch interface and the RJ-45 patch cable that hooks them together.
  • VN-Link requires platform support for Port Profiles, Virtual Ethernet Interfaces, Virtual Center Integration, and Virtual Ethernet mobility.


So we have two solution to achieve this VN-Link. VN-Link with the Cisco Nexus 1000v and VN-Link with the Cisco Nexus 5000. We will explore each option now and shall tell you the tradeoff in between these two.

VN-Link With the Cisco Nexus 1000V

Cisco Nexus 1000V – Software Based

  • Industry’s first third-party ESX switch
  • Built on Cisco NX-OS
  • Compatible with switching platforms
  • Maintain vCenter provisioning model unmodified for server administration but also allow network administration of Nexus 1000V via familiar Cisco NX-OS CLI

VN-Link with the Cisco Nexus 5000

Nexus Switch with VN-Link - Hardware Based

  • Allows scalable hardware-based implementations through hardware switches
  • Standards-based initiative: Cisco & VMware proposal in IEEE 802 to specify “Network Interface Virtualization”
  • Combines VM and physical network operations into one managed node
  • Future availability

Now to do a Tradeoff I will show you a picture, which will tell you all you need.



About Prasenjit Sarkar

Prasenjit Sarkar is a Product Manager at Oracle for their Public Cloud with primary focus on Cloud Strategy, Cloud Native Applications and API Platform. His primary focus is driving Oracle’s Cloud Computing business with commercial and public sector customers; helping to shape and deliver on a strategy to build broad use of Oracle’s Infrastructure as a Service (IaaS) offerings such as Compute, Storage, Network & Database as a Service. He is also responsible for developing public/private cloud integration strategies, customer’s Cloud Computing architecture vision, future state architectures, and implementable architecture roadmaps in the context of the public, private, and hybrid cloud computing solutions Oracle can offer.

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