This refers to the operating system's kernel where deep packet inspection (DPI) and complex firewall rules are enforced. If a packet cannot be "accelerated" at the physical or hardware level, it is sent to the kernel (the "slow path") for more intensive processing. Check Point CheckMates Key Concepts in Deep Post-Analysis
It is not a single software or hardware solution but a hybrid methodology. PSLK combines three distinct disciplines:
“This is for everyone out there,” she said, her voice small but steady. “My mommy says the world forgot how to be happy. So I drew you a happy thing. It’s called a Sky Hound. He eats clouds and barps rainbows. I hope you like him.”