Examkin

Soru

Zorluk: ZorComparing Traditional Networks with Controller-Based Networking

A network architect is analyzing the architectural differences during a migration from a legacy campus network to a controller-based software-defined networking (SDN) model. In the legacy environment, switches operate using a traditional distributed control plane, whereas the new architecture utilizes a centralized SDN controller. Which statement accurately describes the fundamental shift in control plane processing and forwarding table management when transitioning to the controller-based model?

  1. The centralized controller assumes responsibility for control plane intelligence and uses Southbound APIs to program forwarding tables directly onto hardware devices, while data plane traffic continues to be forwarded locally by the physical switches.Cevap
  2. B
    Physical switches continue computing independent control plane routing tables using distributed routing protocols, while using Northbound REST APIs to push local routing tables to the controller for centralized telemetry.
  3. C
    The SDN controller executes agentless SSH CLI scripts to update device running-configurations in real-time, requiring individual switches to re-converge local distributed routing protocols upon receiving configuration updates.
  4. D
    Centralizing the control plane requires all user data plane traffic to be encapsulated and hairpinned back through the SDN controller so the controller can inspect and route every payload packet.

Cevap

The centralized controller assumes responsibility for control plane intelligence and uses Southbound APIs to program forwarding tables directly onto hardware devices, while data plane traffic continues to be forwarded locally by the physical switches.
In traditional networking, each network node maintains both its own control plane (calculating topologies and paths) and data plane (forwarding frames/packets). In controller-based networking, the control plane is abstracted and centralized within the controller. The controller uses Southbound APIs to push compiled forwarding policies down to physical network devices, allowing the switches to execute data plane packet forwarding at hardware wire speed without having to compute topology calculations independently.

Adım Adım Çözüm

1
Identify the traditional network control plane characteristics
Traditional network switches run distributed control plane protocols (e.g., OSPF, EIGRP, STP) locally on every device to independently build routing and MAC address tables.
Understanding legacy architecture establishes the baseline distributed control plane model.
2
Identify the controller-based (SDN) network characteristics
SDN decouples the control plane from physical devices and centralizes it into a software controller.
Centralization enables global network visibility, automated policy enforcement, and programmatic control.
3
Differentiate interface roles (Northbound vs Southbound APIs) and plane separation
The controller uses Southbound interfaces (APIs/protocols like OpenFlow, NETCONF, RESTCONF) to communicate down to networking hardware, programming the local data planes for distributed line-rate forwarding. Northbound APIs interact upwards with applications and management software.
This confirms that data plane forwarding remains local on physical switch ASICs while control plane logic is offloaded to the controller.

Anahtar Kavram

Separation of Control Plane and Data Plane in SDN vs Traditional Distributed Control Planes
Tahmini Süre:1m 30s
Bu soruyu puanla

Konular

Comparing Traditional Networks with Controller-Based Networking

Bu konudan daha fazla soru