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Running Stratum on a Barefoot Tofino based switch

Getting Started with Pre-Build Docker Images

The Docker image contains pre-built Stratum binaries, latest Barefoot Software Development Environment (SDE) binaries, and some required configuration files.

For more information, visit the docker directory.

Building Stratum from Scratch

If you want or need to build Stratum yourself or if you need to make changes to how the BF SDE is built, you can follow these instructions.

Note: To do this, you will need to have SELA with Intel (Barefoot) to access P4 Studio SDE. Contact Intel for more details.

First, choose the location where you will be installing the SDE. This environment variable MUST be set for the Stratum build.

export BF_SDE_INSTALL=...
export PI_INSTALL=$BF_SDE_INSTALL

BSP or BSP-less mode (with ONLP)?

Stratum can be run on Tofino-based platforms in 2 different modes:

  • if your platform comes with ONLPv2 and a JSON "port mapping" file is provided by the platform vendor (see this example for the Wedge 100bf-32x), you can use Stratum in "BSP-less mode". Refer to this section for more information. This is the recommended mode.
  • otherwise, you need to build & install the BSP. You will not be able to use the Stratum ONLP support.

Installing the SDE

These instructions are valid for SDE versions 8.8.0 through 8.9.0. Barefoot's P4Studio Build tool comes with a default Stratum profile, which takes care of installing all the necessary dependencies and builds the SDE with the appropriate flags.

Please follow these steps:

  1. Extract the SDE: tar -xzvf bf-sde-<SDE_VERSION>.tgz

  2. Set the required environment variables

export SDE=`pwd`/bf-sde-<SDE_VERSION>
export SDE_INSTALL=$BF_SDE_INSTALL
  1. Build and install the SDE. Use the provided profile (stratum_profile.yaml). Feel free to customize the profile if needed; please refer to the P4Studio Build documentation. If you are using the reference BSP provided by Barefoot, you may also use P4Studio Build to install the BSP (see below). Also, we drop Thrift support in Stratum, the Stratum profile will be updated in next version. Now you need to remove the Thrift dependency by using sed command (see below) if you are using SDE version 8.8.0 or 8.9.1.
cd $SDE/p4studio_build
sed -i.bak '/package_dependencies/d; /thrift/d' profiles/stratum_profile.yaml  # For SDE version <= 8.9.1
./p4studio_build.py -up profiles/stratum_profile.yaml

If your platform supports BSP-less mode (recommended), you do not need to install the BSP. Refer to the section below.

Installing the reference BSP for the Wedge

Ignore this section if your platform supports ONLPv2 and BSP-less mode.

If you are using the reference BSP provided by Barefoot (for the Wedge switch), you may use P4Studio Build to install the BSP. All you need to do is extract the BSP tarball and use an extra command-line option when running P4Studio Build:

tar -xzvf bf-reference-bsp-<SDE_VERSION>.tgz
export BSP_PATH=`pwd`/bf-reference-bsp-<SDE_VERSION>

Replace step 3 in the sequence above with:

cd $SDE/p4studio_build
sed -i.bak '/package_dependencies/d; /thrift/d' profiles/stratum_profile.yaml  # For SDE version <= 8.9.1
./p4studio_build.py -up profiles/stratum_profile.yaml --bsp-path $BSP_PATH

You may also still install the BSP manually. If you are not using the reference BSP, you will need to install the BSP yourself (under $BF_SDE_INSTALL) based on your vendor's instructions.

Building the binary

If your platform comes with ONLPv2 and you want to use Stratum in BSP-less mode, you may want to set the ONLP_INSTALL environment variable to point to your ONLP installation before building stratum_bf. You can also build stratum_bf without setting ONLP_INSTALL, in which case the default ONLP library will be downloaded and we will build against it. This is useful if you are building stratum_bf for simulation, or if you are not building it directly on the switch (in this case just make sure the correct ONLP library for your platform is loaded at runtime).

bazel build //stratum/hal/bin/barefoot:stratum_bf

Running the binary (with BSP or Tofino software model)

sudo LD_LIBRARY_PATH=$BF_SDE_INSTALL/lib \
     ./bazel-bin/stratum/hal/bin/barefoot/stratum_bf \
       --external_stratum_urls=0.0.0.0:28000 \
       --grpc_max_recv_msg_size=256 \
       --bf_sde_install=$BF_SDE_INSTALL \
       --persistent_config_dir=<config dir> \
       --forwarding_pipeline_configs_file=<config dir>/p4_pipeline.pb.txt \
       --chassis_config_file=<config dir>/chassis_config.pb.txt \
       --write_req_log_file=<config dir>/p4_writes.pb.txt \
       --bf_sim

For a sample chassis_config.pb.txt file, see sample_config.pb.txt in this directory. Do not use the ucli or the Thrift PAL RPC service for port configuration. You may use the ucli to check port status (pm show).

The --bf_sim flag tells Stratum not to use the Phal ONLP implementation, but PhalSim, a "fake" Phal implementation, instead. Use this flag when you are using a vendor-provided BSP or running Stratum with the Tofino software model.

Running the binary in BSP-less mode

If ONLP support is available for your platform, you do not need to use a BSP. Instead the platform vendor can provide a JSON "port mapping" file (see this example for the Wedge 100bf-32x) and Stratum takes care of making the information exposed by ONLP available to the SDE as needed.

To start Stratum in BSP-less mode, copy the JSON port mapping file for your platform to $BF_SDE_INSTALL/share and run stratum_bf with --bf_switchd_cfg=stratum/hal/bin/barefoot/tofino_skip_p4_no_bsp.conf.

Platforms with repeaters (such as the Wedge 100bf-65x) are not currently supported in BSP-less mode.

We only support DAC cables at the moment, and autoneg must be forced "on" for every port. See sample_config.pb.txt for an example (look for autoneg: TRI_STATE_TRUE). We are working on adding support for optical cables.

By default FEC is turned off for every port. You can turn on FEC for a given port in the chassis config file by adding fec_mode: FEC_MODE_ON to the config_params message field for the appropriate singleton port entry. FEC will then be configured automatically based on the port speed: Firecode for 10G and 40G, Reed-Solomon for all other speeds (25G, 50G, 100G and other supported port speeds). For example:

singleton_ports {
  id: 132
  port: 132
  speed_bps: 100000000000
  config_params {
    admin_state: ADMIN_STATE_ENABLED
    autoneg: TRI_STATE_TRUE
    fec_mode: FEC_MODE_ON
  }
  node: 1
  name: "132"
  slot: 1
}

will configure device port 132 in 100G mode with Reed-Solomon (RS) FEC.

FEC can also be configured when adding a port through gNMI.

Testing gNMI

You can use the tools/gnmi/gnmi-cli.py script for gNMI get, set, and subscriptions:

python tools/gnmi/gnmi-cli.py --grpc-addr 0.0.0.0:28000 get /interfaces/interface[name=128]/state/ifindex
python tools/gnmi/gnmi-cli.py --grpc-addr 0.0.0.0:28000 set /interfaces/interface[name=1/1/1]/config/health-indicator --string-val GOOD
python tools/gnmi/gnmi-cli.py --grpc-addr 0.0.0.0:28000 sub /interfaces/interface[name=128]/state/oper-status

Using p4runtime-shell

p4runtime-shell is an interactive Python shell for P4Runtime. While it can also be used to set the P4 forwarding pipeline and issue P4Runtime Write RPCs, it especially comes in handy when you want to read the forwarding state of the switch.

To start a shell session, you can use (requires Docker):

./p4runtime-sh-docker --grpc-addr <Stratum IP>:28000 --device-id 1 --election-id 0,1

Refer to the p4runtime-shell documentation for more information.