Multicast allows to send information, for example audio or video streams, sensor data or service discovery messages, to many interested recipients with minimal overhead, without the need of a central, beefy server. A perfect fit with a decentral network like dn42 (https://dn42.dev/) or Freifunk (https://freifunk.net/)?
The fundamental standards for multicast aren't new but usable, "bugfree" implementations have been rare in the past. And multicast is typically not available on common consumer internet connections.
The former has changed though, great progress was made in OpenSource software, including Freifunk firmwares and mesh routing protocols, in recent years. Allowing us to experiment with this and potentially making it available to and from a wider, public, distributed audience and providers.
To really unfold the potential of multicast and to tackle the chicken & egg problem it will be crucial to establish a multicast topology with a wide reach. So let's start with making our hackspaces and community networks multicast interconnected!
This session will kick off with a small presentation on IPv6 multicast routing. Followed by a practical, hands-on workshop to set up IPv6 multicast peerings based on PIM-SD (https://www.rfc-editor.org/rfc/rfc7761) over dn42. While the presented tooling will focus on bird (https://bird.network.cz/) with a dedicated BGP multicast channel + pim6sd (https://github.com/troglobit/pim6sd) experimentation and discussion on other tools (maybe FRR?) and approaches will be highly encouraged.
Prerequisites: For the workshop part you should have a dn42 node or other BGP enabled router set up and connected beforehand and should have some experience with IPv6 unicast routing. Also feel free to stop by in the #dn42-multicast IRC channel on HackInt (https://hackint.org/) in advance. Having some more "beta testers" and potential people to onboard others during the session would be appreciated :-).
If you are a commercial ISP or research institute with potential multicast peering opportunities for our community networks then we would also be very interested to hear from you.