My scenario is the head office has two links primary link is DXX which is terminated on router and secondary link is PRI which is terminated on access server. The remote branch connect to head office using DXX as primary link and isdn as backup link. If the primary link DXX is down the remote branch router dial to head office Access Server through isdn and connect to head office i have configured DDR for this scenario. It works fine.
Now there is a problem there is another geographical site DR is coming which is the backup of headoffice site. The DR site has one access server if the main head office site is down the remote branch will dial to DR site access server to use the applications. Now i am confused how to configure backup of DDR. Configuration is attached.