if it's ok to create vpn on layer 3 (one more hop between subnets) - go for tun. if you need to bridge two ethernet segments in two different locations - then use tap. in such setup you can have computers in the same ip subnet (eg 10.0.0.0/24) on both ends of vpn, and they'll be able to 'talk' to each other directly without any changes in their routing tables. vpn will act like ethernet switch
Types of VPNs, VPNs and Logical Systems, Understanding Layer 3 VPNs, Supported Layer 3 VPN Standards, Understanding Layer 3 VPN Forwarding Through the Core, Understanding Layer 3 VPN Attributes, Routers in a VPN, Introduction to Configuring Layer 3 VPNs A virtual private network (VPN) extends a private network across a public network and allows end hosts to perform data communication across shared or public networks. In early years, Layer 2 VPNs were pretty popular and later on came Layer 3 VPNs which started picking up pace. Both the VPN types have their own pros and cons. Internet Protocol security (IPsec) VPNs have been dominant for a number of years. The technology works at OSI Layer 3 to create a "tunnel" into the network, so that as devices log on, they act as if they are physically attached to the LAN. Secure Socket Layer (SSL) VPNs work at Layer 4, the application layer. Layer 1 (Physical): Actual hardware sits at this layer. It transmits signals over media. The TCP/IP model, sometimes referred to as a protocol stack, can be considered a condensed version of the OSI model. Layer 1 (Network Access): Also called the Link or Network Interface layer. This layer combines the OSI model’s L1 and L2. This guide serves as an introduction to Layer 3 VPN architectures. As you consider different virtual private network types for your enterprise WAN, such as MPLS, IPsec, SSL and remote, be mindful of the traffic you want to transmit (data, voice, etc.), the business factors that may dictate future scalability needs and the resources you have to manage and administer a VPN. At the moment, the debate between Layer 2 VPN services based on MPLS and Layer 3 MPLS VPNs is largely theoretical; Layer 2 VPN service are not widely available yet.. But the two are different
Oct 03, 2019
Layer 2 vs. Layer 3 VPNs | Network World
Internet Protocol security (IPsec) VPNs have been dominant for a number of years. The technology works at OSI Layer 3 to create a "tunnel" into the network, so that as devices log on, they act as if they are physically attached to the LAN. Secure Socket Layer (SSL) VPNs work at Layer 4, the application layer.
Physical Layer (Layer 1) : The lowest layer of the OSI reference model is the physical layer. It is … Blog | What is the Difference Between VPN and IP VPN