Two of the most well-known protocols used by SDN Controllers to communicate with the switches/routers is OpenFlow and OVSDB. Others protocols that could be used by an SDN Controller is YANG or NetConf. Other SDN Controller protocols are being developed, while more established networking protocols are finding ways to run in an SDN environment. For example, the Internet Engineering Task Force (IETF) working group – the Interface to the Routing System (i2rs) – is developing an SDN standard that enables an SDN Controller to leverage proven, traditional protocols, such as OSPF, MPLS, BGP, and IS-IS.