Additional requirements:

• Must both support what is necessary for the previous two architecture (Router Solicitation,Router Announcement, and Dynamic routing filtering)

This is a rather powerful architecture, since it allows concentrating both the routing and the security policy in one device; however this concentration makes the particular architecture less susceptible to the security problems:

• More functionality should be integrated into one device. That makes it more complex and opens the possibility of more security problems
• Since it is only one device the principle of security: protect your network/service with more than one asset, cannot be fulfilled.

This setup is very common in home or small office environments, where a single xDSL, or cable router provides connectivity and in the same time enforces the security policy defined by the network administrator.