From the definition of Reverse Route Injection, I have understood that it creates static route entries for remote vpn destinations in VPN gateway, so that it can redistribute the routes into into it's local network. What I don't get is, why there is a need for Reverse Route Injetion? Why can't we just redistribute a default route into the local network pointing towards the firewall for all the vpn traffic when all you have is a single vpn gateway?
Your example with a single gateway is a very simple network, and in that case you don't need RRI, as you have figured out.
But, many networks are more complex than your example. Here are a few reasons why using RRI would be helpful.
- The default gateway may be different than the VPN gateway.
- There may be more than one VPN gateway, and you need to know which one is used.
- There may be several subnets used for VPN endpoints. Dynamically injecting them may be simpler.
There are probably other use cases as well. Generally speaking, many Cisco features were created to solve specific problems found in larger, more complex networks. They aren't necessary for a simple network as you've described.