This post describes how to set up your Obi to take advantage of GVGW server redundancy. Thanks to user CarlM for this write-up!
The starting point for these instructions is GVGW already configured under Service Providers->ITSP Profile X and working.
Obihai Config Instructions
Under Service Providers->ITSP Profile X->SIP:
1. Set all four of the following parameters to gvgw.simonics.com :
ProxyServer (this should have been set already)
2. Enable X_ProxyServerRedundancy
3. Enable X_DnsSrvAutoPrefix
4. Submit the changes
5. Reboot your Obi
It is neither necessary nor desirable to enable X_SecondaryRegistration. In the case of GVGW, registering with one server registers you with all servers.