A set of documents you may find useful:

Building an Internet Router

• Design Process Overview
• SimpleSumeSwitch in Mininet

Learning P4

• P4 Tutorial 1 - Introduction to Data Plane Programming
• P4 Tutorial 2 - Basics Part I
• P4 Tutorial 3 - Basics Part II
• P4 Tutorial 4 - Basic Tunneling Application

Xilinx SDNet

• P4-SDNet User Guide
• p4c-sdnet missing P4 features

SUME Event Switch

• SUME Event Switch