vnigade/tutorials

P4 language tutorials

P4 Tutorial

Introduction

Welcome to the P4 Tutorial! We've prepared a set of exercises to help you get started with P4 programming, organized into several modules:

1. Introduction and Language Basics

• Basic Forwarding
• Basic Tunneling

2. P4Runtime and the Control Plane

• P4Runtime

3. Monitoring and Debugging

• Explicit Congestion Notification
• Multi-Hop Route Inspection

4. Advanced Behavior

• Source Routing
• Calculator
• Load Balancing

5. Stateful Packet Processing

• Firewall
• Link Monitoring

Presentation

The slides are available online and in the P4_tutorial.pdf in the tutorial directory.

A P4 Cheat Sheet is also available online which contains various examples that you can refer to.

Obtaining required software

If you are starting this tutorial at one of the proctored tutorial events, then we've already provided you with a virtual machine that has all of the required software installed. Ask an instructor for a USB stick with the VM image.

Otherwise, to complete the exercises, you will need to either build a virtual machine or install several dependencies.

To build the virtual machine:

• Install Vagrant and VirtualBox
• Clone the repository
• Before proceeding, ensure that your system has at least 25 Gbytes of free disk space, otherwise the installation can fail in unpredictable ways.
• cd vm
• vagrant up - This step typically takes over 1 hour to complete, and requires a reliable Internet connection throughout.
• When the machine reboots, you should have a graphical desktop machine with the required software pre-installed. There are two user accounts on the VM, vagrant (password vagrant) and p4 (password p4). The account p4 should be logged in when the VM boots up by default, and is the one you are expected to use.

Note: Before running the vagrant up command, make sure you have enabled virtualization in your environment; otherwise you may get a "VT-x is disabled in the BIOS for both all CPU modes" error. Check this for enabling it in virtualbox and/or BIOS for different system configurations.

You will need the script to execute to completion before you can see the p4 login on your virtual machine's GUI. In some cases, the vagrant up command brings up only the default vagrant login with the password vagrant. Dependencies may or may not have been installed for you to proceed with running P4 programs. Please refer the existing issues to help fix your problem or create a new one if your specific problem isn't addressed there.

To install dependencies by hand, please reference the vm installation scripts. They contain the dependencies, versions, and installation procedure. You should be able to run them directly on an Ubuntu 16.04 machine:

• sudo ./root-bootstrap.sh
• sudo ./user-bootstrap.sh