The OpenVPN solution you are mentioning. Is IMHO only really nessesary og you have plans for further sites in the near future and do not want to renumber and/or change your BGP configuration in regards to how you peer with $ISP.
A possible option is to announce both Main sites /24 and a cover /23 announcement. On Satellite site announce its own allocated /24 (no. 2 subnet out of /23). Then traffic will always go to the /24 for satellite site. If you decide to scale satellite sites I the future. Just change your configuration only for satellite site. As Main site is already properly configured. Another option is also. If you use the exact same $ISP for all sites. Allow the ISP to announce the /23 on your behalf. And sub allocate everything between! /24-/30's prefixes to your sites. As long as the same ISP are used for all sites and the are allowed to announce the /23 on your behalf. This is a viable alternative, too. (You could do either static routing or bgp with private ASN with ISP in this scenario) -- have you enabled IPv6 on something today...? Chriztoffer 📧 from 📱 device.
