Network Planes

CCNA Planes: Control, Data, Management, Operational

Which plane of a network device is responsible for forwarding packets based on the routing or switching table?
A. Control plane
B. Management plane
C. Data plane
D. Operational plane

C — Data plane. It’s the hardware-driven forwarding engine that applies the logic built by the control plane to move actual user traffic.

The control plane primarily performs which function?
A. Executes packet forwarding in hardware
B. Learns routes, builds tables, and exchanges routing updates
C. Handles device configuration and SSH access
D. Implements business intent in SDN controllers

B — Control plane. It runs protocols like OSPF, BGP, and EIGRP, deciding the best paths and updating the routing and neighbor tables.

When you configure a router via SSH or HTTPS, which internal plane handles this communication?
A. Data plane
B. Control plane
C. Management plane
D. Policy plane

C — Management plane. It manages administrative traffic and remote access interfaces like SSH, SNMP, and HTTPS, separated from data traffic for security.

What happens if the control plane of a router fails but the data plane stays operational?
A. The router cannot forward existing traffic.
B. The router continues forwarding based on existing tables but cannot learn new routes.
C. The router reverts to a default static route.
D. The router redirects all traffic to the management plane.

B — Forwarding continues using the existing FIB (Forwarding Information Base), but dynamic updates and topology changes stop until the control plane recovers.

In a Cisco SD-WAN or DNA Center environment, the operational (policy) plane primarily does what?
A. Determines shortest paths with SPF algorithm
B. Directly forwards user data traffic
C. Converts business intent into network configuration and policy enforcement
D. Provides command-line management access

C — Operational or policy plane. It acts as the orchestration layer that translates intent or policy into configurations distributed to network devices.

Which plane is most isolated for security reasons and often resides on a separate VRF or out-of-band network?
A. Data plane
B. Management plane
C. Control plane
D. Policy plane

B — Management plane. It’s isolated from data forwarding to protect administrative interfaces and minimize exposure to attack surfaces.

When a router sends an OSPF Hello packet, which plane generates it?
A. Data plane
B. Control plane
C. Management plane
D. Policy plane

B — Control plane. Routing protocol traffic originates from the control plane to build and maintain neighbor adjacencies and routing information.

An ACL denying Telnet access to a router’s VTY lines protects which plane?
A. Data
B. Control
C. Management
D. Policy

C — Management plane. Restricting administrative access (e.g., via ACLs or AAA) safeguards management functions from unauthorized users.

QoS marking and packet classification occur at which plane?
A. Control
B. Management
C. Data
D. Policy

C — Data plane. Quality-of-Service enforcement and traffic shaping occur as packets traverse the forwarding path, handled by hardware ASICs.

Which statement accurately describes how the control plane interacts with the data plane?
A. The control plane forwards packets directly through CPU processing.
B. The control plane builds forwarding tables that the data plane uses to make decisions.
C. The control plane and data plane perform identical functions.
D. The control plane encrypts management sessions.

B — The control plane creates the routing and switching databases; the data plane references them to forward packets efficiently without CPU intervention