Why use l2tp with ipsec

The L2TP picked up its features and functionalities from the protocols mentioned above and significantly improved on them. It was published at the turn of the 20th century to replace the above-listed protocols and became the standard RF C These are the points between which L2TP tunneling happens. The first step in L2TP tunneling is establishing a connection between the two endpoints listed above.

When this connection is active, a PPP layer is enabled and encapsulated. This is what is moved around the web later on.

A free slot is then assigned within the Network tunnel, and the request is passed on to the LNS. When the connection has received thorough authentication and is accepted, a virtual PPP interface is created. Once this is done, the link frames can pass freely through the tunnel. This is the processing of frames once they are accepted, and L2TP encapsulation is removed. You must have come across the acronym IPSec several times in this article.

It stands for Internet Protocol Security. It provides encryption security for data that are passed from one computer to another. The L2TP is not best as a stand-alone. If it were a stand-alone, the L2TP would be extremely fast.

You're now online. This encrypting part happens first, before the L2TP connection is made, but everything from that point on is exactly the dialup analogy. Why isn't GRE used for mobile users? And if you don't need ethernet framing at all — just doing things like standard applications web browsing, etc or utilizing BGP — you don't need any layer on top of bare IPsec. So in short, you usually use bare IPsec when you have static configurations between two endpoints.

Layer two tunneling protocol, as the name implies, provides a layer 2 link over an arbitrary L3 network. Since you probably don't want your data center traffic traversing the Internet unprotected, you use IPSec to keep your traffic confidential. Sign up to join this community. The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Asked 4 years, 11 months ago. Active 4 years, 11 months ago.

Viewed 3k times. Improve this question. Imagine a bunch of system at a data centre, and mobile workers who use a VPN to work on them. It is desirable to tunnel L2 traffic over routed L3 networks because L2 networks are generally more transparent, easier to configure and easier to manage than L3 networks.

These are desirable properties for a range of applications. In data centers, a flat network is essential for promoting virtual machine VM mobility between physical hosts. In companies with multiple premises, the sharing of infrastructure and resources between remote offices can be simplified by L2 tunneling. This article concentrates on the latest Version 3 of the specification, which describes tunneling multiple L2 protocols over various types of packet-switched networks PSN.

An L2TP connection comprises two components: a tunnel and a session. The session is logically contained within the tunnel and carries user data. A single tunnel may contain multiple sessions, with user data kept separate by session identifier numbers in the L2TP data encapsulation headers.

Conspicuously absent from the L2TP specification are any security or authentication mechanisms. This gives L2TP the flexibility to interoperate with various different security mechanisms within a network. The four use cases discussed below illustrate how L2TP works in a variety of scenarios, from simple point-to-point links to large networks. Whether you're running a single-site corporate LAN or a complicated multi-site network, L2TP has the scalability to fit into your architecture.

Today, with diverse mobile devices used throughout businesses , and pervasive availability of broadband in the home, most corporate networks must provide remote access as a basic necessity. Virtual private network VPN technologies are an essential part of meeting that need. Figure 1 shows a simplified VPN configuration. Remote workers and mobile devices may join the corporate network via IPSec-secured L2TP tunnels over any intermediate network most likely the Internet.