scc365/p4-tutorial

P4 tutorial

This tutorial is based on a number of tools developed as part of the P4 foundation and the NGSDN tutorial repos.

The tutorial consists of two task:

• Basic Forwarding with P4: this tutorial will allow you to exercise your P4 language knowledge and understand some key characteristics of the language.
• P4 network calculator: This tutorial will get you to work with the control plane of the P4 language.

Before progressing to the details, you need first to install a couple of additional Python package for the GRPC control channel. Simply type make install on any of the tutorial folder.

Toolchain

The tooling for this tutorial will be based on Docker images maintained by the P4 foundation. We will will basically utilize two main docker containers. The p4c container contains all the compiler binaries, required to compile P4 programs. In this tutorial we will be using the open-soruce P4C compiler, maintained by the P4 foundation. The stratum_bmv2 conrtainer contains a modified version of the Mininet framework and add support for the P4 Behavioural Model v2 switch, a reference implementation of the P4 switch specifications.

In order to simplify the P4 development, we provide you with a Makefile that automates some several tasks. The action that you can execute are:

• make p4-build: This action will compile the file p4src/main.p4 in the respective exercise window and generate the required switch pipeline files in the folder p4src/build, i.e., the p4src/build/bmv2.json (The specification file for the switch), and ithep4src/build/p4info.txt (Required to generate the p4 bindinds., and p4src/build/p4info.txt ()) files.
• make proto-build: Generate the python bindings to run a GRPC client that can connect to the P4 switch. The binding are required to run the util/simple_controller.py, a Python executable that allows you to inject custom flows into a running P4 switch.
• make start, make stop, make restart: You can use these Makefile actions to control the mininet network.
• make mn-cli: This action will open a mininet terminal so that you can run mininet commands. In order to exit from the terminal, you should use the shortcut Ctrl+D. If you type exit, this will stop the whole Mininet instance and you will have to restart.
• make mn-logs: This action will display the mininet log. This is only for debugging purposses.

Next steps ...

Now that you became familiar with the toolchain of this tutorial you can start working on the first exercise. Just open the exercise1/README.md to figure out what you have to.