VXLAN versus GENEVE (NSX-V vs. NSX-T)
August 14th, 2021 With the ramp-up of NSX-T overlay networks and transition away from NSX-V overlay networks, it's a good time to look at one of the fundamental differences between them. NSX-V uses VXLAN as its encapsulation protocol while NSX-T uses the more recent GENEVE encapsulation protocol. Each require the physical networking devices have their MTU adjusted to 1600 bytes or greater. We'll take a detailed look at why that is. First, the basics: VXLAN is: short for Virtual eXtensible Local Area Network Is defined in rfc 7348 - https://datatracker.ietf.org/doc/html/rfc7348 Uses UDP port 4789 8 byte header GENEVE is: short for Generic Network Virtualization Encapsulation Is defined in rfc 8926 - https://datatracker.ietf.org/doc/html/rfc8926 Uses UDP port 6081 16 byte header From the prospective of the physical network, an overlay network is essentially an application. NSX-T is an application using well known UDP port 6081. Switching perspectives to the overlay's