What is SDN?
SDN decouples the network control plane (which decides how traffic should flow) from the data plane (which forwards packets according to those decisions), enabling centralised, software-based control of network behaviour. SDN principles are foundational to the 5G Core’s CUPS architecture and the transport networks that support 5G slicing.
How Does SDN Work?
In SDN, a centralised controller programs forwarding rules into data plane devices using standardised protocols (OpenFlow, NETCONF/YANG, P4). In 5G: the SMF acts as an SDN controller for the UPF (via PFCP/N4 interface); the transport network uses SDN for traffic engineering and slice-aware routing (SRv6, MPLS-TE); Open RAN’s RIC uses SDN concepts to programmatically control radio resource management.
Use Cases
5G Core user plane programmability, slice-aware transport network management, NFV orchestration for virtual network functions, Open RAN intelligent control via xApps.
3GPP / Standards Reference
ONF SDN Architecture, 3GPP TS 23.501 (CUPS with SDN principles), ETSI NFV-INF
Related Terms
CUPS | UPF | Open RAN | Network Slicing
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This glossary entry is part of the 5GWorldPro Complete 5G Glossary. To go deeper into 5G architecture and technology, explore our 5G Training courses.
