Which next-hop packet forwarding protocol is used with SDN switching networks?

The equal-cost multipath routing (ECMP) packet forwarding protocol is used to calculate next-hop forwarding with SDN switching networks. The Open Shortest Path First (OSPF) protocol is a layer 3 routing protocol and not used with SDN switching networks. The Multiprotocol Label Switching Protocol (MPLS) is a protocol used with MPLS wide area network (WAN) providers and not used with SDN switching networks. The CLOS network is also known as a Leaf/Spine network, but it is the topology and not a next-hop packet forwarding protocol.