dataplanes

Dataplane refers to the portion of a network device responsible for forwarding data packets and applying per-packet actions. It operates at high speed and is implemented in hardware, software, or a combination thereof. The dataplane executes forwarding decisions based on rules configured by the control plane and enforces policies such as routing, switching, filtering, shaping, and tunneling.

In traditional networks, the dataplane is a fixed-function component embedded in routers or switches, optimized for line-rate throughput. Modern deployments increasingly use software dataplanes on general-purpose hardware, or programmable dataplanes that can be reconfigured without changing hardware. A typical dataplane pipeline consists of match-action stages where input packets are classified and directed to a specific action, such as forwarding to an output port, dropping, modifying headers, or encapsulating in a tunnel.

Programmable dataplanes enable operators to customize behavior using high-level languages and toolchains. Examples include P4, eBPF/XDP, and DPDK-based stacks. These enable features such as QoS, NAT, load balancing, and encapsulation (VXLAN, GRE) to be offloaded to specialized hardware or accelerated in software. SmartNICs and programmable NICs are common platforms for programmable dataplanes.

Dataplane function is distinct from the control plane, which runs routing protocols, topology discovery, and configuration logic. In software-defined networking, the control plane programs the dataplane via protocols such as OpenFlow or via northbound APIs, while management interfaces provide observability and policy management.

Key considerations include achieving line-rate performance, low latency, and predictable behavior, as well as hardware costs and energy use. Data-plane design must balance fast-path performance with the flexibility to implement new policies, while ensuring security and resilience against misconfiguration and attacks.