At my work, we build mobile networks from scratch for customers regularly. (Mobile Networks: think battery powered LTE router with wifi.) Since we build from scratch we can be vendor agnostic and research ways to keep costs down.
There's the saying that to a hammer every problem is a nail. (To a cisco guy, every product can be solved with a Cisco Solution.) I'm a strong believer in using the right tool for the job. Thus I decided to work on a mental model of the strengths/best usage scenarios of different secure/trustworthy VPN technologies. Then develop a working proficiency of each to add to my toolkit.
Here are noteworthy VPN types/protocols I'm reading up on. Note I've omitted VPN technologies I believe to be insecure or untrustworthy (NSA backdoors).
- IKEv2/IPSec: (I read it's a better version of L2TP, that it can reestablish VPN connection, when the internet flaps, or switches between multiple networks, home, work, cellular.)
- openVPN: Best for security. It's been audited. I'd like to know if it supports multicast. (I've read somewhere that it doesn't, but I also heard someone mentioned it can with a bridged mode.)
- SoftEtherVPN: Creates a virtual hub that emulates a hardware switch, so can do multicast. It also has NAT Transversal features, which make it so you can have a VPN server behind a firewall that people can connect to without having to edit any firewall settings. (I think it's through a cloud relay).
- GRE/IPSec VPN Tunnel: 2 Routers (cisco, pfsense, etc) can form a site to site link using this, which will allow multicast traffic. (Is this a site to site router only VPN protocol?)
Question: Of the aforementioned VPN tunnel protocols/types, which support multicast traffic inherently, transparently, or with minimal configuration.