2.2.1.3.2 Layer Two Tunneling Agreement (L2TP)

PPTP is a Layer 2 agreement that encapsulates PPP frames in IP datagrams for manual over an IP internetwork, such as the Internet. PPTP can be acclimated for limited admission and router-to-router VPN connections. PPTP is accurate in RFC 2637.

The Point-to-Point Tunneling Agreement (PPTP) uses a TCP affiliation for adit aliment and a adapted adaptation of Generic Routing Encapsulation (GRE) to abbreviate PPP frames for tunneled data. The payloads of the encapsulated PPP frames can be encrypted and/or compressed. Figure 6 shows the anatomy of a PPTP packet absolute user data.

2.2.1.3.2 Layer Two Tunneling Agreement (L2TP)

L2TP is a aggregate of PPTP and Layer 2 Forwarding (L2F), a technology proposed by Cisco Systems, Inc. L2TP represents the best appearance of PPTP and L2F. L2TP encapsulates PPP frames to be beatific over IP, X.25, Frame Relay, or Asynchronous Transfer Mode (ATM) networks. When configured to use IP as its datagram transport, L2TP can be acclimated as a tunneling agreement over the Internet. L2TP is accurate in RFC 2661.

L2TP over IP internetworks uses UDP and a alternation of L2TP letters for adit maintenance. L2TP aswell uses UDP to forward L2TP-encapsulated PPP frames as the tunneled data. The payloads of encapsulated PPP frames can be encrypted and/or compressed.