How does Palo Alto’s single‑pass parallel processing architecture work

Palo Alto Networks’ Single-Pass Parallel Processing (SP3) architecture is the core of its firewall design. It’s built to deliver high performance and low latency without compromising security accuracy. This architecture combines two key components:

1. Single-Pass Architecture

"Classify once, apply many"

The firewall inspects traffic only once, extracting all the necessary information in a single pass through the data plane. Instead of having separate engines for App-ID, Threat-ID, and Content-ID each scan the traffic independently, the SP3 architecture processes it just once.

🔹 What happens during a single pass:

• Packet decoding

• Application identification (App-ID)

• User identification (User-ID)

• Content inspection (Content-ID)

• Threat prevention (Threat-ID)

• URL filtering

• Data Loss Prevention (DLP)

All these services use the same stream of data — no redundant processing.

Benefits:

• Lower latency — no need to reprocess traffic for each feature

• Higher throughput — efficient resource usage

• Consistent security — all engines work on the same extracted metadata

2. Parallel Processing (Multi-Core Architecture)

"Do many things at the same time"

The firewall uses a multi-core CPU architecture, where different processing engines run in parallel on separate cores. Each function is optimized and assigned to its own processor or processing group.

🔹 Key planes involved:

Within the Data Plane, parallel processors handle:

• Networking (routing, switching, NAT)

• Security (App-ID, Content-ID, Threat-ID)

• Decryption (SSL/TLS)

• Forwarding (session handling, traffic shaping)

 Benefits:

• Scalability — can handle more traffic by adding more cores

• Efficiency — each core does a specific job, avoiding bottlenecks

• High performance — enables full-feature inspection at line rate