VPNs at different OSI layers
Network layer VPNs (Layer-3)
Created using layer 3 tunneling and/or encryption
Q: difference between encapsulation and tunneling ?
Example: IPsec, GRE, L2TP (tunneling layer 2 traffic by using the IP layer to do that)
A ‘proper’ layer
Low enough: transparency
High enough: IP addressing
Cisco focuses on this layer for its VPNs.