Why SDN Is the Key to Elastic Hybrid Cloud Networks

As public cloud services mature, enterprises increasingly adopt them, starting with non‑critical workloads and gradually moving critical applications, while some workloads remain on private clouds; thus hybrid cloud becomes the fundamental IT architecture.

On‑Demand Network Is a Basic Requirement for Cloud Services

Hybrid cloud brings the dual benefits of public and private clouds but also faces challenges such as network interoperability, latency, multi‑vendor heterogeneity, and elastic scaling of network resources alongside cloud resources.

Massive data‑center and business scale demand higher network performance. Growing numbers of users, data‑center size, and traffic require dynamic scaling and higher capacity, deployment speed, and convergence performance.

Unified orchestration across data‑centers and VPN connectivity. Inter‑data‑center links must span long distances and external networks while supporting unified orchestration for automatic workload migration between private and public clouds.

Multi‑vendor interconnectivity. Hybrid cloud infrastructures involve heterogeneous vendors; seamless integration, unified control, and operation are essential.

E2E integration of data‑center, campus, and WAN (IP/optical) networks. Deploying workloads to the cloud extends user‑data distance, requiring unified management that breaks network boundaries to present a single resource pool.

Application‑driven on‑demand networking. Networks defined from a business perspective enable automatic, elastic resource scheduling, achieving “network follows cloud” connectivity.

SDN Architecture: The Best Choice for Cross‑Cloud Connectivity

SDN redefines network capabilities through software, delivering on‑demand elasticity, reduced operational costs (over 40% savings), and improved utilization and fault tolerance. For example, Huawei’s Agile Controller helped Century Internet raise link utilization from 50% to 80%.

SDN enables Network‑as‑a‑Service (NaaS), on‑demand bandwidth, and aligns with hybrid cloud needs. Key capabilities include:

Elastic and scalable network management. Controller clusters and alliances provide distributed control, supporting large‑scale device management and fault tolerance.

End‑to‑end full‑scene control. SDN solutions span campus, WAN (IP/MPLS, optical), and data‑center networks, offering on‑demand resource acquisition, automated deployment, and intelligent optimization.

Northbound openness. Programmable networks expose resources as services, enabling integration with cloud management platforms and BSS/OSS.

Southbound multi‑vendor support. Plugins abstract heterogeneous devices into logical resources, allowing third‑party VAS integration.

High reliability. Distributed controller clusters, redundant links, and transaction mechanisms ensure continuous operation.

Intelligent networking. Global topology and business‑state monitoring enable real‑time, application‑aware traffic engineering and self‑healing operations.

Figure 1: Controller cluster and alliance supporting network elasticity.

Figure 2: SDN solution achieving end‑to‑end full‑scene control.

Figure 3: Distributed mechanisms for cluster reliability and disaster recovery.

Figure 4: SDN enabling intelligent network operation.

SDN Deployment Rhythm and Business Practice

The evolution follows a flexible three‑step path: “point → line → surface”.

Phase 1 – “Point”: Deploy single‑domain SDN solutions. Start with single data‑center, WAN, or campus scenarios, creating overlay tunnels for rapid site‑to‑site or site‑to‑cloud connectivity.

Phase 2 – “Line”: Connect across scenarios. After successful pilots, extend to cross‑domain networks, integrating DCN with DCI, multi‑domain control, and IP‑plus‑optical coordination for dynamic bandwidth and latency provisioning.

Phase 3 – “Surface”: Cloud‑control‑edge collaboration for end‑to‑end NaaS. Transition from overlay to underlay, unifying the entire network as a resource pool that dynamically adapts to cloud demands, delivering QoS for 4K video, video conferencing, IoT, 5G, and finance.

Huawei’s SDN solutions have been deployed in large carrier cases such as Deutsche Telekom and China Telecom, demonstrating the commercial viability of hybrid‑cloud‑oriented networking.

In summary, hybrid cloud requires an on‑demand, elastic network, and SDN provides the open, reliable, scalable, and intelligent foundation to meet this demand.