P4 Developer Day

A presentation by the P4 Language Consortium

Held at Stanford University on Wednesday, June 6, 2018

Special Thanks to our Sponsors:

Virtual Machine

We have created a virtual machine that has all of the software needed to complete the developer day exercises already installed. You can either download a virtual machine image or build it from source. Note that both of these procedures can take around 45 minutes depending on the speed of your network connection.

• To download the virtual machine image
  1. Install VirtualBox
     https://virtualbox.org
  2. Download virtual machine image
     P4 Tutorial 2018-06-01.ova
  3. Import virtual machine into VirtualBox
     Open VirtualBox, select “File > Import Appliance”, and navigate to the downloaded file.
  4. Boot virtual machine
     Select “P4 Tutorial 2018-06-01”, and click “Start”.
• To build the virtual machine from source
  1. Install VirtualBox
     https://virtualbox.org
  2. Install Vagrant
     https://vagrantup.com
  3. Clone the tutorial repository
     $ git clone https://github.com/p4lang/tutorials
  4. Navigate to the vm directory
     $ cd tutorials/vm/
  5. Build the virtual machine
     $ vagrant up
• Final steps
  After the machine boots, you should have a graphical desktop with all required software pre-installed, logged in as username “p4” (with password “p4”).

Slack

We will use Slack to make it easy for participants to ask the TAs questions.

• Register at bit.ly/join-p4-lang-slack
• Join the #d2-2018-spring channel

Pigeonhole

We will use Pigeonhole to manage questions during the panel.

• Register at pigenhole.at
• Enter the event code P4D2

Slides

The slides presented by the instructors at the developer day can be accessed here.

P4 Cheat Sheet

The P4 cheat sheet that was distribtued to attendees at the developer day can be accessed here.

Agenda

• 8:00 – 8:30am
  • Registration and Breakfast

• 8:30 – 9:00am
  • Technical Set-up for Hands-on LabIn order to complete the Developer Day exercises, we will distribute a virtual machine with all required software installed.

• 9:00 – 9:10am
  • Welcome and IntroductionsSpeaker: Nate Foster (Cornell University)

• 9:10 – 10:30am
  • Introduction to Data Plane ProgrammingInstructor: Stephen Ibanez (Stanford University)
  • Language BasicsInstructor: Stephen Ibanez (Stanford University)Session 1 will provide a hand-on introduction to P4. Students will start by implementing a “Hello World”-style application to gain an understanding of P4 concepts. The lesson will progressively introduce core language features, such as header/metadata types, packet parsers, and controls. By the end of this session, students will be able to implement a basic IP router.

• 10:30 – 11:00am
  • Break

• 11:00 – 12:30
  • P4 RuntimeInstructor: Brian O’Connor (ONF) Session 2 will cover software tools that are essential to developing P4 applications. Students will learn how to invoke the the P4 compiler, run the debugger, and start a P4 software switch. This session will also introduce the control-plane interfaces via P4 Runtime, a protocol-independent API auto-generated from the definition of a packet processing pipeline written in P4.

• 12:30 – 1:30pm
  • Lunch

• 1:30 – 2:00pm
  • Keynote: “Revisiting In-Network Control” Arvind Krishnamurthy (Washington)Abstract: Emerging programmable switches allow for flexible and reconfigurable packet processing at line rate. These emerging technologies address a key limitation with traditional SDN solutions that allow for only custom-plane customization but not data-plane customization needed by traffic management protocols that perform “in-network” control and per-packet processing.Despite their promising new functionality, reconfigurable switches are not all-powerful; they have limited state, support limited types of operations, and limit per-packet computation in order to be able to operate at line rate. In this talk, I describe how we can address these limitations by using novel approximation techniques and implement previously unrealized protocols that require in-network control. Our work thus represents a modest step towards enabling a “software defined data plane” that provides greater performance and isolation for datacenter applications.

• 2:00-3:00
  • Monitoring and DebuggingInstructor: Mina Tahmasbi Arashloo (Princeton University)Session 3 will focus on a set of labs related to network monitoring and debugging. In this session, students will gain a deeper understanding of P4 language concepts, including custom headers and intrinsic metadata. In the first exercise, students will implement Explicit Congestion Notification (ECN) to set a congestion bit in a packet header when the queue depth exceeds a threshold. In the second exercise, MRI, students will implement a simplified version of In-Band Network Telemetry to track the path that packets travel through the network.

• 3:00 – 3:30pm
  • Break

• 3:30 – 4:30pm
  • Advanced Data StructuresInstructor: Nate Foster (Cornell University)Session 4 covers advanced data structures. In this session, students will implement two data-plane applications. In the first, source routing, end-hosts specify paths through the network by using a stack of labels in the packet header. The switch must “pop” each label and forward out the appropriate interface. In the second, students will implement a network calculator. Packets containing arithmetic expressions are sent to a switch. The switch will evaluate the expressions, and return the results back to the sender.
• 4:30-5:30
  • Panel DiscussionModerator: Ben Pfaff (VMware)Panelists:
    • Bochra Boughzala (Kaloom)
    • Uyen Chau (ON.Lab)
    • Chris Sommers (Keysight)

• 5:30-6:30
  • Reception