VXLAN… vSphere vCNS vs NSX for vSphere

During VMWorld I was asked about VXLAN and thought I would share with you as well…

VXLAN is VMware’s network encapsulation technology used in VMware vCloud Networking & Security products and NSX for vSphere. It is also used by switch vendors Arista, Juniper, Broadcom, HP, and others to provide top of rack integration with VMware’s NSX for Multi Hypervisor via VXLAN Tunnel EndPoint or VTEP for short…

Before going forward, I just want to clarify that VXLAN is one of many current encapsulation technologies available, and there are newer encapsulation¬†technologies in development… It works today and if something better comes along, well its just software ūüėČ

vSphere vCNS VXLAN

Available in vCloud Networking and Security (vCNS) working together with vSphere Distributed Switches provides the ability to create Logical L2 Switches or Virtual Wires. If you need to deploy VXLAN across an L3 data center network, you are required to deploy L3 Multicast across your data center network.

Many guides and blogs are available which document the deployment of VXLAN in vCNS including:


NSX for vSphere

The fundamental difference between vCNS and NSX is that NSX is “controller based” which means the NSX controller cluster is¬†tracking and managing hypervisor virtual network constructs.

From a VXLAN perspective, this allows¬†VXLAN in an NSX for vSphere environment to be deployed without requiring L3 Multicast to be configured across the data center network, although if you are comfortable with L3 Multicast, it is also a deployment option. Ideally, an¬†optimal deployment is actually what we¬†call “Hybrid Mode” where we can take advantage of L2 Switch Multicast capabilities (IGMP Snooping etc) while using Unicast across L3.

Unicast VXLAN certainly simplifies the implementation of software defined networking given the only requirement for physical network changes is implementing a 1600 byte MTU or larger.





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