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Zorluk: OrtaSeparation of Control Plane and Data Plane

An enterprise organization implements a Software-Defined Networking (SDN) architecture that decouples control plane operations to a centralized controller while maintaining distributed data plane operations on edge switches. If the Southbound API connection between an edge switch and the centralized controller fails unexpectedly, how does the switch handle existing, established data traffic?

  1. The switch continues forwarding established traffic streams locally using its pre-populated hardware forwarding tables.Cevap
  2. B
    The switch immediately halts all data plane forwarding because each packet lookup requires active approval from the central controller.
  3. C
    The switch converts incoming transit data packets into ARP broadcast frames to dynamically discover new paths across the physical network.
  4. D
    The switch punts all data plane packets directly to its local CPU to calculate new topology routes independently.

Cevap

The switch continues forwarding established traffic streams locally using its pre-populated hardware forwarding tables.
In controller-based architectures with decoupled planes, the control plane programs the local data plane hardware (ASICs/TCAM) via Southbound APIs. Once forwarding tables (FIB) are established, the data plane handles packet forwarding autonomously at wire speed. Consequently, a loss of connection to the centralized controller prevents new control updates but allows existing, established data streams to continue forwarding locally without interruption.

Adım Adım Çözüm

1
Analyze the functional responsibilities of the control plane versus the data plane in SDN architectures.
The control plane makes policy decisions and builds routing/forwarding structures (RIB), whereas the data plane performs high-speed packet switching based on programmed forwarding tables (FIB/TCAM).
Decoupling control and data planes isolates packet-level forwarding from control traffic processing.
2
Evaluate the state of the data plane when the Southbound connection to the centralized control plane is interrupted.
The local ASIC/TCAM forwarding tables on the network switch retain previously programmed instructions.
Data plane hardware does not need active controller communication for every packet lookup; it forwards transit packets autonomously based on installed FIB entries.

Anahtar Kavram

Decoupled Control and Data Plane Resilience
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Konular

Separation of Control Plane and Data Plane

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