WiMoVE - Wireless Mobility through VXLAN EVPN

WiMoVE is a scalable Wi-Fi System that partitions all stations in separate overlay L2 domains to limit the amount of wireless L2 broadcast traffic. In large Wi-Fi systems, broadcast traffic can take up large amounts of airtime. A great talk that explains the problem in more detail is available here. In WiMoVE, overlay L2 domains "follow" the stations, being resized on demand, thus preserving handover.

WiMoVE is built with standard network protocols, on top of open‑source technology:

The overlay networks use BGP EVPN with VXLAN encapsulation.
All BGP speakers run FRRouting to exchange EVPN routes.
The access points run OpenWrt with our custom, open‑source daemon called wimoved.

This solution allows for using commodity access points running OpenWrt for large‑scale Wi‑Fi deployments, even from different vendors.

This repository

This repository contains the WiMoVE Access Point daemon wimoved. The daemon is responsible for handling hostapd events and creating VXLAN interfaces. WiMoVE consists of multiple other parts. If you want to learn more about the architecture or create a full setup, take a look at our documentation.

Supported architectures

Currently, we support OpenWrt with the architectures ramips-mt7621 and mvebu-cortexa9. We test our software on the Access Point models ZyXEL NWA50AX and Linksys WRT1900ACS. If you need support for other OpenWrt architectures, feel free to open an issue.

Development setup

The development setup is an easy way to test wimoved. Please be aware that after following this guide, you do not have a full WiMoVE installation. You can connect to the Wi-Fi but won't be connected to other devices or the Internet. If you want a complete WiMoVE setup, follow the setup guide instead. Currently, we only support Linux as a development platform.

Setup hostapd

First, we will set up hostapd.

Install hostapd using your distribution's package manager. Alternatively, you can build it from source, see here. By default, hostapd comes with VLAN support. If you encounter issues, make sure that it was compiled with CONFIG_NO_VLAN=n.
Put the following in your /etc/hostapd.conf, replacing the placeholder values:

    interface=<interface>
    ssid=<ssid>
    ieee80211d=1
    country_code=<Your country code>
    hw_mode=g
    ieee80211n=1
    channel=6
    beacon_int=1000
    dtim_period=2
    max_num_sta=255
    rts_threshold=-1
    fragm_threshold=-1
    macaddr_acl=0
    auth_algs=1
    ignore_broadcast_ssid=0
    wmm_enabled=0
    eapol_key_index_workaround=0
    eap_server=0
    wpa=2
    wpa_key_mgmt=WPA-PSK
    rsn_pairwise=CCMP
    wpa_passphrase=<Secret key>
    per_sta_vif=1
    vlan_file=/etc/hostapd/hostapd.vlan

Create a file /etc/hostapd/hostapd.vlan with the following content:

*   vlan#

Hostapd has to be started with the option -g /var/run/hostapd/global. For the service to work properly, you might have to edit the service file for hostapd. Run systemctl status hostapd to locate this file.
Start hostapd, either with systemctl start hostapd or on the command line. You might need to stop NetworkManager before starting hostapd since the programs interfere with each other.

Build WiMoVE

Install libnl. On a recent Linux system, the corresponding package is probably already installed.
Install prometheus-cpp.
- On Ubuntu, install the package prometheus-cpp-dev.
- On Arch Linux, the package is available in the AUR as prometheus-cpp-git.
Clone the repository by running git clone https://github.com/WiMoVE-OSS/wimoved.
Build the project by running cmake . followed by make -j$(nproc).
Start wimoved by running ./wimoved.

Coding guidelines

Format the source files by running make format. Lint the source files by running make lint. Build the tests by running make test. Run both checks and the tests by doing make precommit. The coding guidelines are enforced via the CI pipeline.

As linting takes a long time, we recommend integrating clang-tidy into your editor.

Sanitization

Build with sanitizers enabled by running cmake . -DWIMOVED_SANITIZE=ON. For full stacktrace support, set the environment variable LSAN_OPTIONS=fast_unwind_on_malloc=0:malloc_context_size=30.

Monitoring and Logging

Monitoring

wimoved exposes metrics via prometheus on port 9500. Via the endpoint, information on how many stations are associated, how many events have been handled and how long the event handling took is exposed. The endpoint is activated by default. We plan on making the endpoint optional via a config option.

Logging

wimoved provides logs via syslog. A syslog aggregator like syslog-ng can be used to aggregate those logs on a different host.

dasGoogle/wimoved-enterprise