I'm desinging a network for 2 eletric substation following some specifications. (see topology.jpg)
I need to provide fully hardware redundancy between two eletric substation, provide encryption and VPN.
I'm planning to use Two cisco 1841 router with AIM VPN module and more 4 ethernet ports at each site.
This network is for security system (CFTV). Will have multicast traffic and some TCP traffic between sites, so I will use GRE Tunnel + IPsec to pass multicast packets.
For hardware redundancy I'm planning to use HSRP + IP sla command to verify the connection.
My client ask me to use NHRP, but i'm not sure how do I will implement NHRP in this solution ? It is not a point-to-point connection When I use GRE Tunnel + IPSec ?
Why I need to use NHRP in this case??
I appreciate if anyone could help me!!!