1. Is it possible to establish site to site VPN tunnel between Site A and Site B note: There is a dedicated link, it is in same subnet 192.168.10.0/30 Valid hosts 192.168.10.1 and 192.168.10.2 (assigned to firewall)
VPN tunnel configuration like Phase 1 and Phase 2 will be configured by default apart from that Site A has route for 10.1.20.0/24 is pointing to 192.168.10.1 and Site B has route for 10.1.10.0/24 is pointing to 192.168.10.2
Whether we can establish VPN tunnel for the above scenario ??????
Refer the attached Diagram.
Hope I explained clearly.
Yes, you can configure site-to-site VPN between site A and site B as per your topology.
Just make sure that the device is capable of terminating VPN tunnels.
I just want to know whether I can have other VPN tunnel from Site A and Site B over internet as well.
Not at the same time. You can't encrypt the same traffic through your WAN link as well as through the Internet.