Cisco Certified Network Associate (CCNA) Practice Exam

Which protocol is used to create a dedicated VPN connection in a site-to-site implementation?

1. Layer 2 Forwarding

2. Point-to-Point Tunneling Protocol

3. Tunnel mode

4. Layer 2 Tunneling Protocol

The correct answer is: Tunnel mode

In the context of creating a dedicated VPN connection in a site-to-site implementation, tunnel mode is the correct choice because it refers specifically to a method used in IPsec VPNs. Tunnel mode encapsulates the entire original IP packet and adds a new IP header, which allows for the secure transmission of data between two sites over the internet. This is crucial for site-to-site VPNs as it provides a secure tunnel through which data can be safely transmitted. While other options like Point-to-Point Tunneling Protocol and Layer 2 Tunneling Protocol are relevant in the broader context of VPN protocols—both are used to establish VPNs and provide tunneling techniques—they typically cater to different scenarios. Point-to-Point Tunneling Protocol, for instance, is more commonly associated with remote access configurations rather than site-to-site connections. Layer 2 Forwarding is not a VPN protocol; it relates instead to the way Ethernet frames are forwarded down a network link, and thus does not apply to the implementation of a site-to-site VPN. In summary, tunnel mode is the key mechanism within IPsec that secures and encapsulates the data for site-to-site VPNs, enabling a dedicated and secure connection between different sites.