Redundant Site to Site VPN with 2 or 3 lines between branches and HQ

Hi

Questions: 1. Is it possible to build redundant site-to-site VPN with above lines? So can load balance and auto fail-over VPN and Internet?

ANS:

    1. static route configuration. you can add multiple static route to same destination with different distance value

    2. config OSPF routing in both end to load balance the VPN 

2. Can choosen application be prioritized?

 ANS :

         specific ip traffic can be route through a particular tunnel. also you can use traffic shaping option

3. What is the recommended Fortigate Model for branches with 30 or 50 users? And HQ if to handle 7 or up to 70 branches.

  ANS :

 for 30 users you can use fortigate 30E and above 50 use Fortigate 60E. in HQ use fortigate 100E for better throughput 4. Any other areas we should look into or take into consideration for this kind of implementation?

ANS :

find a fortinet partner 5. It is possible if we only use 1 broadband and 1 3G/4G line with both running Dynamic IP?

ANS :

better use a dedicated lease line in HQ with static ip address. you can also use fortiddns free dynamic dns service

Regards

Mahesh