Hi, I am trying to understand how SDNs can dramatically change the networking paradigm and this is my understanding. Yahoo, Google, etc applications are running on one server and each application could be theoretically associated with a unique VXLAN tag. This way service providers will be able to provide QoS per application (by effectively providing QoS to the VXLAN carried in the pkts). So now Youtube for example, can get unique QoS treatment from our desktops to the edge of the network. Form there on core routing will pick up - which remains largely unaffected by VXLANs. OpenFlow is useful because it provides a common "CLI/SNMP" with which all routers from all vendors can be provisioned and monitored. As an example, VPLS configuration in Juniper, CIsco and AlaLu routers will be very different. So, provisioning a VPLS service in a network that comprises of these 3 vendors would require the admins to know the CLIs of all these routers. If these routers support OpenFlow, then theoretically, one configuration would work on all routers. OpenFlow would like say "Provision a LSP" and each router will internally provision an LSP. The admin remains oblivious to the internal CLIs of these boxes. The SDN controller is a SW that can again theoretically be made aware of the entire network. It can look at SNMP traps, etc and can figure out the exact topology of the network. Based on the SNMP traps, messages it can determine all failures in the network. It can run routing protocol simulations and figure out the best topology in the network. This can, using OpenFlow, be programmed on all routers. So, all heavy CPU processing task is taken over by the SDN controller. The controller can also take in requests on what network aware applications require and feed that to the routers/switches in the network and thus you have an application aware network provisioned. I understand that this is just some bit of what we can do with SDN. The amount of what all can be done is limitless. So, a question to all out there - Is my understanding of what can be achieved with SDN, is correct? Glen