FlexRIC

This repository contains O-RAN Alliance compliant E2 node Agent emulators, a NearRT-RIC, xApps written in C/C++ and Python, as well as patches to 5G/4G OpenAirInterface and 4G srsRAN. It implements various service models (NG/GTP, PDCP, RLC, MAC, KPM v2, SC, TC) and a built-in emulation. Depending on the service model, different encoding schemes have been developed (ASN.1, flatbuffer, plain). The indication data received in the xApp uses as persistence mechanism an sqlite3 database for enabling offline processing applications (e.g., ML/AI).

If you want to know more about FlexRIC and its original architecture, you can find more details at: Robert Schmidt, Mikel Irazabal, and Navid Nikaein. 2021. FlexRIC: an SDK for next-generation SD-RANs. In Proceedings of the 17th International Conference on emerging Networking EXperiments and Technologies (CoNEXT '21). Association for Computing Machinery, New York, NY, USA, 411–425. DOI: https://doi.org/10.1145/3485983.3494870. A pdf copy is available at https://bit.ly/3uOXuCV

Below is the list of features available in this version divided per component and per service model:

1. Installation

1.1 Install prerequisites

• A recent CMake (at least v3.22).

  On Ubuntu, you might want to use this PPA to install an up-to-date version.

• SWIG (at least v.4.0).

  We use SWIG as an interface generator to enable the multi-language feature (i.e., C/C++ and Python) for the xApps. Please, check your SWIG version (i.e, swig -version) and install it from scratch if necessary as described here: https://swig.org/svn.html or via the code below:

  git clone https://github.com/swig/swig.git
  cd swig
  git checkout release-4.1
  ./autogen.sh
  ./configure --prefix=/usr/
  make -j8
  make install

• Flatbuffer encoding(optional).

  We also provide a flatbuffers encoding/decoding scheme as alternative to ASN.1. In case that you want to use it follow the instructions at https://github.com/dvidelabs/flatcc and provide the path for the lib and include when selecting it at ccmake .. from the build directory

1.2 Download the required dependencies.

Below an example of how to install it in ubuntu

sudo apt install libsctp-dev python3.8 cmake-curses-gui libpcre2-dev python-dev

1.3 Clone the FlexRIC project, build and install it.

• Download the code

  # i.e.: 
  $ git clone https://gitlab.eurecom.fr/mosaic5g/flexric.git 

• Build

  $ cd flexric && mkdir build && cd build && cmake .. && make 

• Install

  You can install the Service Models (SM) in your computer via:

  sudo make install

  By default the service model libraries will be installed in the path /usr/local/lib/flexric while the configuration file in /usr/local/etc/flexric.

1.4 Test (optional step)

There are some tests you can run. Precisely:

• Service Model unit test. See directory build/test/sm
• 3 nodes test. See directory build/examples/xApp/c/monitor. This test simulates an scenario with an E2 node's, a nearRT-RIC and an xApp. Data is randomly filled. Example running in 3 terminals.

  # terminal 1: start E2 Node agent
  ./build/examples/emulator/agent/agent_1
  # terminal 2: start nearRT-RIC
  ./build/examples/ric/nearRT-RIC
  # terminal 3
  build/examples/xApp/c/monitor/xapp_mac_rlc_pdcp_moni

• All-in-one test. See directory build/test/agent-ric-xapp

Most of the tests can be triggered using ctest. From the build directory launch ctest to start the tests.

2. Usage/deployment

Before starting the nearRT-RIC, check that the IP address where your nearRT-RIC will be listening is the desired one at /usr/local/lib/flexric/flexric.conf. The default configuration assumes that all the components are located in localhost.

Start the nearRT-RIC with:

$ ./build/examples/ric/nearRT-RIC

Start one or multiple E2 node Agent emulators using default configuration

$ ./build/examples/emulator/agent/emu_agent_gnb_cu
$ ./build/examples/emulator/agent/emu_agnet_gnb_du

or a customized one, i.e.:

$ ./build/examples/emulator/agent/emu_agent_gnb_cu -c ~/flexric1.conf &
$ ./build/examples/emulator/agent/emu_agnet_gnb_du -c ~/flexric2.conf &

where, for example, flexric1.conf is:

[NEAR-RIC]
NEAR_RIC_IP = 127.0.0.1

[XAPP]
DB_PATH = /tmp/
DB_NAME = xapp_db1

flexric2.conf is:

[NEAR-RIC]
NEAR_RIC_IP = 127.0.0.1

[XAPP]
DB_PATH = /tmp/
DB_NAME = xapp_db2

Next, you can fetch some statistics from the E2 Agents using python xApps via $ python3 build/examples/xApp/python3/xapp_gtp_moni.py, while in other window you can start a second xApp developed in c $ build/examples/xApp/c/monitor/xapp_monitor_all

You can also start wireshark and see how E2AP messages are flowing. At this point, FlexRIC is working correctly in your computer and you have already tested the multi-agent, multi-xApp and multi-language capabilities.

The latency that you observe in your monitor xApp is the latency from the E2 Agent to the nearRT-RIC and xApp. In modern computers the latency should be less than 200 microseconds or 50x faster than the O-RAN specified maximum nearRT-RIC latency of 10 ms. Additionally, all the data received in the xApp is also written to /tmp/xapp_db in case that offline data processing is wanted (e.g., Machine Learning/Artificial Intelligence applications). Please, check the example folder for other working xApp use cases.

3. Integration with RAN and example of deployment

3.1 Integration with OpenAirInterface 4G/5G RAN

We will use the patch provided in flexric repository

$ git clone https://gitlab.eurecom.fr/oai/openairinterface5g.git oai
$ cd oai/
$ git checkout 2022.41
$ git am path/to/flexric/multiRAT/oai/oai.patch --whitespace=nowarn
$ source oaienv
$ cd cmake_targets
$ ./build_oai -I -w USRP -i  #For OAI first time installation
$ ./build_oai --eNB --gNB -c -C -w USRP --ninja

Prepare you favourite hot/cold beverage as the compilation of OAI may take 10 minutes. Example configuration files using a B210 USRP are provided to facilitate the integration.

In this release MAC, RLC, PDCP SMs are operative for 5G/4G and slicing for 4G

3.2 Integration with srsRAN 4G RAN

Install srsRAN from source https://docs.srsran.com/en/latest/general/source/1_installation.html#installation-from-source and follow their instructions.

cd path/to/srsran
git checkout release_21_10
git am path/to/flexric/multiRAT/srsran/srsenb.patch --whitespace=nowarn
mkdir build && cmake .. && make -j8 
cd srsenb/src/
sudo ./srsenb

In this release MAC, RLC, PDCP and partially Slicing are supported SMs.

3.3 (opt) Synchronize clock

Before running the various components (RAN/flexric), you probably want to align the machines' clock. At this aim, you can use ptp4l in all the machines involved (if you have for example deployed the various components on different hosts)

sudo ptp4l -m -i InterfaceName #for master
sudo ptp4l -m -i InterfaceName -s #for slaves

Following make sure that no ntpd, chrondy or timesyncd is running in the system (e.g., sudo systemctl stop systemd-timesyncd).

sudo phc2sys -m -s InterfaceName -w

3.4 Start the processes

• Start some eNodeB/gNodeB

  Below an example with 5G or 4G OAI gNodeB/eNodeB

  # eNB
  $ cd oai/cmake_targets/ran_build/build
  $ sudo ./lte-softmodem -O path/to/flexric/multiRAT/oai/enb.band7.tm1.25PRB.usrpb210.replay.conf
  
  # gNB
  $ cd oai/cmake_targets/ran_build/build
  $ sudo ./nr-softmodem -O path/to/flexric/multiRAT/oai/gnb.sa.band78.fr1.106PRB.usrpb210.conf --sa -E --continuous-tx

• Start the nearRT-RIC

  $ ./build/examples/ric/nearRT-RIC

• Start different xApps

  e.g, start the monitoring xApp with build/examples/xApp/c/monitor/xapp_mac_rlc_pdcp_moni. The monitoring sequence diagram is represented below:

  

  e.g, start the slicing control xApp via $ python3 build/examples/xApp/python3/xapp_slice_moni_ctrl.py. The controlling sequence diagram is represented below:

  

4. Support/further resources

• Mailing list: if you need help, you can subscribe to the mailing list techs@mosaic-5g.io that you can find at https://gitlab.eurecom.fr/mosaic5g/mosaic5g/-/wikis/mailing-lists
• demo: here you can find a demo
• wiki page
• ppt presentation with a gentle introduction to flexric
• Original FlexRIC paper ACM CoNEXT 2021

5. Roadmap

Check https://gitlab.eurecom.fr/mosaic5g/flexric/-/milestones