Our company developed a data network infrastructure based on OSPF IP routing protocol. Regarding the great number of branches we chose to split OSPF domain in 6 OSPF areas, each area having between 6 and 8 routers .
Now we are in phase of implementing a communication through the network by using GRE tunneling, regarding the special protocol that must be tunneled.
As the areas are configured with summarization on border routers, every area receveing a dedicated IP addresses scheme, we have some questions regarding the IP addresses nedded to be use on GRE tunneling.
1. Do we need to use for GRE tunneling other IP addresses than those established for OSPF areas ?
2. Do we need to have a dedicated ethernet interface in every branch for the IP segment that must be tunneled ?
3. Can we use OSPF as routing protocol for the traffic passing the tunnel ? What implications reffers to ( a special area for the tunnel ???) ?
Thanks for your support