The Case for the Software Defined Edge

Despite the hype, the use of Software Defined Networking (SDN) has been limited to simple management tasks. This results both from the narrow interface between the dataand control-plane in today’s SDN designs and from the inherent limitations of enforcing policies at switches. We propose Sweden, a software-defined edge architecture for enforcing management policies in closed environments like datacenters. Sweden enforces the policies at end hosts with minimal network support. It decomposes administrator specified policy programs into program fragments that (i) require global visibility and hence, run at a centralized controller, (ii) need to be responsive and hence, run at the end host, (iii) need to be on the data path and hence, run at the network interface (NIC). For the last part, Sweden leverages programmable NICs and exposes a programmable match-action API, thus allowing delegation of control logic and state to the NIC. Through examples, we show how such end-based management improves control-plane scalability and responsiveness while allowing for richer policies than previous proposals.