The control plane contains the functions that determine how the data plane forwards traffic. It performs the overhead work needed to establish forwarding rules and state, rather than forwarding messages directly. section 22.2.1 section 22.4
Typical control-plane functions include:
- Using OSPF to share routing information and build a routing table. section 22.2.1
- Using ARP to build a table that maps IP addresses to MAC addresses. section 22.2.1
- Supporting operational functions such as Syslog event logging, NTP time synchronization, and SSH access. section 22.2.1
- Operating in a distributed form on traditional network devices or through centralized controller functions in SDN. section 22.4
Traditional routing and SDN
In a traditional network, each router runs OSPF, learns routes, and builds its own routing table. In SDN, a controller centralizes some or all control-plane functions and instructs distributed data planes how to forward messages. section 22.4
