The OSI model is that thing that everyone seems to love to hate. The OSI is actually just a model that has its roots in the International Organization for Standardization. We’ve all had disagreements how certain protocols map to certain layers. However, it has certainly stood the test of time. What is interesting to me is how the datacenter has and is continuing to transform. When we think about modern datacenters and how virtualization is being introduced, many networks today have actual physical, data link and network layers. On top of that we have the upper 6 layers existing in a virtual infrastructure.
My expanded model is certainly not a model that is endorsed by the ISO, but it is a way to help describe the components that are commonly found. Most current datacenters have an underlying physical component that maps well to the bottom three layers of the OSI model. One of the more active areas of innovation actually lives between the physical data-link, physical network and the virtual data-link layers. Here we find evolving technologies like OTV (Overlay Transport Virtualization), VXLAN and NVGRE. While virtualization is a cool concept and the ability to move a virtual host from one physical host is a reality, challenges remain when these need to be moved from datacenter to datacenter. Beyond the issues of latency exists the challenges of readdressing (or coming up with a workaround). These new innovations, specifically VXLAN and NVGRE seem to offer hope that there will be a real and automagic workaround by understanding the physical network layer and how the virtual data-link and network layers of hosts are located on top of it. This is an exciting direction that will certainly create some fun and interesting datacenter designs.