This directory contains source code and instructions to run the ONOS+P4 tutorial exercises. Goal of the exercises is to learn how to use ONOS to control P4-capable devices via P4Runtime, and how to write ONOS apps to control custom data plane capabilities implemented in P4.
For help, please write to the mailing list brigade-p4@onosproject.org or check the mailing list archives.
To complete the exercises, you will need to download and run the following VM (in .ova format):
http://onlab.vicci.org/onos/onos-p4-tutorial.ova
To run the VM you can use any modern virtualization system, although we recommend using VirtualBox. To download VirtualBox and import the VM use the following links:
For more information on the content of the VM and minimum system requirements, click here.
The VM comes with one user with sudo privileges. Use these credentials to log in:
sdnrocksThese exercises are based on a simple P4 program called mytunnel.p4 designed for this tutorial.
To start, have a look a the P4 program. Even if this is the first time you see P4 code, the program has been commented to provide an understanding of the pipeline behavior to anyone with basic programming and networking background. While checking the P4 program, try answering the following questions:
t_l2_fwd?t_l2_fwd? E.g. exact match, ternary, or longest-prefix match?t_l2_fwd? What's the next table applied to the packet?Click here to see the solution to these questions
The mytunnel.p4 program is provided to ONOS as part of a "pipeconf".
The main class used to implement the pipeconf is PipeconfFactory.java. This class is declared as an OSGi runtime component which is "activated" once the pipeconf app is loaded in ONOS. The main purpose of this class is to instantiate the Pipeconf object and register that with the corresponding service in ONOS. This is where we associate ONOS driver behaviors with the pipeconf, and also define the necessary pipeconf extensions to be able to deploy the P4 program to a device.
This pipeconf contains:
mytunnel.json: The JSON configuration used to execute the P4 program on BMv2. This is an output of the P4 compiler for BMv2.
mytunnel.p4info: P4Info file obtained from the P4 compiler.
PipelineInterpreterImpl.java: Implementation of the PipelineInterpreter ONOS driver behavior. The main purpose of this class is to provide a mapping between ONOS constructs and P4 program-specific ones, for example methods to map ONOS well-known header fields and packet forwarding/manipulation actions to those defined in the P4 program. For a more detailed explanation of each method, check the PipelineInterpreter interface.
PortStatisticsDiscoveryImpl.java: Implementation of the PortStatisticsDiscovery ONOS driver behavior. As the name suggests, this behavior is used to report statistics on the switch ports to ONOS, e.g. number of packets/bytes received and transmitted for each port. This implementation works by reading the value of two P4 counters defined in mytunnel.p4, tx_port_counter and rx_port_counter.
This app is used to provide connectivity between each pair of hosts via the MyTunnel protocol, a non-standard tunneling protocol created for this exercise. The implementation of this app can be found here, and it will be discussed in more details on Exercise 2.
Click here to go to this exercise instructions
This exercise shows how to start ONOS and Mininet with BMv2, it also demonstrates connectivity between hosts using the pipeline-agnostic app Reactive Forwarding, in combination with other well known ONOS services such as Proxy ARP, Host Location Provider, and LLDP Link Discovery.
Click here to go to this exercise instructions
Similar to exercise 1, but here connectivity between hosts is demonstrated using pipeline-specific app "MyTunnel".