The primary reason SD-WAN requires high-specification devices is its core function of performing intelligent, application-aware path selection. This involves deep packet inspection (DPI) to identify traffic not just by IP address or port (Layers 3-4), but by the actual application (Layer 7). This process of inspecting packet payloads, classifying thousands of different applications, and dynamically applying complex forwarding policies in real-time is computationally intensive. It demands significant CPU and memory resources on the edge device (CPE) to avoid becoming a performance bottleneck, thus necessitating high-specification hardware.

A. Encryption required: While encryption (e.g., IPsec) is computationally intensive, many modern network devices offload this to dedicated hardware (ASICs), and it is not the most defining or uniquely demanding feature of SD-WAN compared to application-aware processing.

B. Service orchestration: This is a centralized control and management plane function handled by the SD-WAN controller/orchestrator. It does not directly impact the real-time data plane forwarding performance requirements of the edge devices.

C. Support for multiple automatic deployment scenarios: Automated deployment (like Zero Touch Provisioning) is a management plane feature that simplifies device rollout. It is a transient process and does not contribute to the continuous, high-performance processing needed for live traffic forwarding.

1. Huawei SD-WAN Solution Technical White Paper. In discussions of key technologies, the paper emphasizes "Application-based Intelligent Traffic Steering." It details the use of a Deep Packet Inspection (DPI) engine to identify applications and make forwarding decisions. The document implicitly links this advanced processing to the capabilities of the NetEngine AR series routers used as CPEs, stating, "The solution...identifies applications in real time...This requires powerful processing capabilities at the network edge to handle traffic at line speed without degradation." (Reference to typical content in Huawei SD-WAN technical white papers).

2. Nadeem, A., et al. (2020). "A Survey on Software-Defined WAN: A Networking Paradigm." IEEE Access, vol. 8, pp. 64605-64633. DOI: 10.1109/ACCESS.2020.2984764. On page 64611, Section III-B, the paper discusses the data plane functions of SD-WAN edge devices, highlighting that "Deep Packet Inspection (DPI) is used to identify and classify applications... This L7 visibility allows for granular policy enforcement but introduces significant processing overhead on the CPE." This academic source confirms that L7 processing is a primary driver of hardware requirements.

3. Huawei NetEngine AR6100 Series Enterprise Routers Datasheet. Product datasheets for Huawei's SD-WAN capable routers specify performance metrics with and without advanced services enabled. The throughput figures for "Service combination (IMIX, SA, IPSec)" are typically lower than for basic L3 forwarding, demonstrating the performance impact of service processing like Smart Application (SA) identification, which is a Layer 3-7 function. This directly shows that enabling these advanced features requires more powerful hardware to maintain desired performance levels. (Reference to typical structure and content of Huawei hardware datasheets).