Active Twin Server?

I was looking at the help page of the new SVN VERSION: 2.4-306a
BUILD: 110310-0311 and I notice there's an Active Twin Server box.
The help page says "Active Twin Server IP - Some vicidial systems require setting up vicidial servers in pairs. This setting is where you can put the server IP of another vicidial server that this server is twinned with. Default is empty for disabled. "
This left me a little bit stumped. Any idea on what might this be? If it is what I think it is, we can run a parallel vicidial/asterisk on the side and if ever the first box crash we can use the second box without reconfiguring?
BUILD: 110310-0311 and I notice there's an Active Twin Server box.
The help page says "Active Twin Server IP - Some vicidial systems require setting up vicidial servers in pairs. This setting is where you can put the server IP of another vicidial server that this server is twinned with. Default is empty for disabled. "
This left me a little bit stumped. Any idea on what might this be? If it is what I think it is, we can run a parallel vicidial/asterisk on the side and if ever the first box crash we can use the second box without reconfiguring?