Thus, the scale and agility of modern data centers put data center networking at odds with the existing network models. Some problems, such as the number of virtual networks, required the development of new technologies such as VXLAN, while others have required a redesign of the network architecture deployed in the data center. But the problem of managing the network is not rooted in any failure of networking, rather in the design of the network OS.

via Your next network operating system is Linux | Networking – InfoWorld.

Essentially, we can write the equivalent of a device driver to synchronize the kernel state of these data structures with the hardware. Silicon switching ports can be made to appear like NICs to the OS. Thanks to Linux’s Netlink model, a device driver can sit by the side and listen to everything that’s going on with the kernel state — interface up/down, routing entries added/deleted either by user or routing protocols, netfilter entries added or deleted — and synchronize that state with the hardware. Furthermore, the driver can sync the state of counters from the hardware with the kernel state allowing native Linux tools such as ethtool, iptables, or /proc/net/dev to display the correct information, completely unaware that these values are coming from the hardware. Cumulus Networks has developed the first such solution, but others with a similar model may not be far away.