Provider-provisioned VPN building-blocks

According Wikipedia, Depending on whether a provider-provisioned VPN (PPVPN)[clarification needed] operates in layer 2 or layer 3, the building blocks described below may be L2 only, L3 only, or combine them both. Multiprotocol label switching (MPLS) functionality blurs the L2-L3 identity.[citation needed][original research?]

RFC 4026 generalized the following terms to cover L2 and L3 VPNs, but they were introduced in RFC 2547.[14] More information on the devices below can also be found in Lewis, Cisco Press.

RFC 4026 generalized the following terms to cover L2 and L3 VPNs, but they were introduced in RFC 2547.[14] More information on the devices below can also be found in Lewis, Cisco Press.[15]

Customer (C) devices
A device that is within a customer’s network and not directly connected to the service provider’s network. C devices are not aware of the VPN.

Customer Edge device (CE)
A device at the edge of the customer’s network which provides access to the PPVPN. Sometimes it’s just a demarcation point between provider and customer responsibility. Other providers allow customers to configure it.

Provider edge device (PE)
A PE is a device, or set of devices, at the edge of the provider network which connects to customer networks through CE devices and presents the provider’s view of the customer site. PEs are aware of the VPNs that connect through them, and maintain VPN state.

Provider device (P)
A P device operates inside the provider’s core network and does not directly interface to any customer endpoint. It might, for example, provide routing for many provider-operated tunnels that belong to different customers’ PPVPNs. While the P device is a key part of implementing PPVPNs, it is not itself VPN-aware and does not maintain VPN state. Its principal role is allowing the service provider to scale its PPVPN offerings, for example, by acting as an aggregation point for multiple PEs. P-to-P connections, in such a role, often are high-capacity optical links between major locations of providers.

Routing

According Wikipedia, Tunneling protocols can operate in a point-to-point network topology that would theoretically not be considered a VPN, because a VPN by definition is expected to support arbitrary and changing sets of network nodes. But since most router implementations support a software-defined tunnel interface, customer-provisioned VPNs often are simply defined tunnels running conventional routing protocols.

Authentication

According to Wikipedia, Tunnel endpoints must be authenticated before secure VPN tunnels can be established. User-created remote-access VPNs may use passwords, biometrics, two-factor authentication or other cryptographic methods. Network-to-network tunnels often use passwords or digital certificates. They permanently store the key to allow the tunnel to establish automatically, without intervention from the user.

Secure Shell (SSH) VPN

According to Wikipedia, Secure Shell (SSH) VPN – OpenSSH offers VPN tunneling (distinct from port forwarding) to secure remote connections to a network or to inter-network links. OpenSSH server provides a limited number of concurrent tunnels. The VPN feature itself does not support personal authentication.

Multi Path Virtual Private Network (MPVPN)

According to Wikipedia, Multi Path Virtual Private Network (MPVPN). Ragula Systems Development Company owns the registered trademark “MPVPN”.

Microsoft Secure Socket Tunneling Protocol (SSTP)

According to Wikipedia, Microsoft Secure Socket Tunneling Protocol (SSTP) tunnels Point-to-Point Protocol (PPP) or Layer 2 Tunneling Protocol traffic through an SSL 3.0 channel. (SSTP was introduced in Windows Server 2008 and in Windows Vista Service Pack 1.)

Microsoft Point-to-Point Encryption (MPPE)

According to Wikipedia, Microsoft Point-to-Point Encryption (MPPE) works with the Point-to-Point Tunneling Protocol and in several compatible implementations on other platforms.

Datagram Transport Layer Security (DTLS)

Datagram Transport Layer Security (DTLS) – used in Cisco AnyConnect VPN and in OpenConnect VPN Virtual Private Network to solve the issues SSL/TLS has with tunneling over UDP.

Transport Layer Security (SSL/TLS)

According to Wikipedia, Transport Layer Security (SSL/TLS) can tunnel an entire network’s traffic (as it does in the OpenVPN project and SoftEther VPN project) or secure an individual connection. A number of vendors provide remote-access VPN capabilities through SSL. An SSL VPN can connect from locations where IPsec runs into trouble with Network Address Translation and firewall rules.

IPSEC – Internet Protocol Security

According to Wikipedia, Internet Protocol Security (IPsec) as initially developed by the Internet Engineering Task Force (IETF) for IPv6, which was required in all standards-compliant implementations of IPv6 before RFC 6434 made it only a recommendation. This standards-based security protocol is also widely used with IPv4 and the Layer 2 Tunneling Protocol. Its design meets most security goals: authentication, integrity, and confidentiality. IPsec uses encryption, encapsulating an IP packet inside an IPsec packet. De-encapsulation happens at the end of the tunnel, where the original IP packet is decrypted and forwarded to its intended destination.