At VMworld 2011, VMware made a big deal about a new networking protocol it has developed in cooperation with server and networking heavyweights like Arista, Broadcom, Cisco, Citrix, and Red Hat. That protocol, Virtual Extensible Local Area Network or VXLAN, promises to ease many of the networking challenges experienced by enterprises and providers attempting to build very large, multitenant networks, such as big private clouds and public IaaS (infrastructure-as-a-service) clouds.
While the introduction of VXLAN was greeted with a great deal of initial enthusiasm, I fear that many have started to imagine it to be a solution to many problems for which it was never designed. Worse, I've come to the realization that the networking community as a whole isn't adapting quickly enough to the rapid innovation taking place in the virtualization and cloud sector -- and VXLAN is a symptom of this failure to deliver open, well-architected innovation.
What is VXLAN?
In the most simplistic sense, VXLAN is a means for a virtualized environment to dynamically provision a very large number of isolated L2 (layer two) networks without requiring any changes to the physical network that serves it. This is accomplished by tunneling L2 traffic within UDP multicast packets that are exchanged between virtual hosts -- essentially creating virtual LANs that are only visible to the virtual hosts and virtual machines that run on them.