L2TP


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L2TP

L2TP

(Layer 2Tunneling Protocol) A protocol from the IETF that lets remote users access the corporate network. L2TP allows a PPP session to travel over multiple links and networks. PPP is used to encapsulate IP packets from the user's PC or mobile device to the ISP, and L2TP extends that session across the Internet. L2TP was derived from Microsoft's Point-to-Point Tunneling Protocol (PPTP) and Cisco's Layer 2 Forwarding (L2F) technology. See PPTP and L2F.

From Access Concentrator to Network Server
The "L2TP Access Concentrator" (LAC) encapsulates PPP frames with L2TP headers and sends them over the Internet as UDP packets (or over an ATM, frame relay or X.25 network). At the other end, the "L2TP Network Server" (LNS) terminates the PPP session and hands the IP packets to the LAN. L2TP software can also be run in the user's PC.

Carriers also use L2TP to offer remote points of presence (POPs) to smaller ISPs. Users in remote locations dial into the carrier's local modem pool, and the carrier's LAC forwards L2TP traffic to the ISP's LNS.

L2TP and IPsec
L2TP does not include encryption (as does PPTP), but is often used with IPsec in order to provide virtual private network (VPN) connections from remote users to the corporate LAN. See PPP, virtual private network and IPsec.


PPP and L2TP Traffic
PPP encapsulates IP packets from the user's PC to the ISP. L2TP tunnels those packets over multiple links.
References in periodicals archive ?
SEGURIDAD: Firewall NAT e inspeccion de paquetes, proteccion contra DoS, prevencion y deteccion de intrusos, encriptacion WEP de 64 y 128 bits, encriptacion WPA-PSK, control de acceso inalambrico, soporta dos tuneles VPN (IPSec, L2TP, PPTP), autenticacion de direccion MAC
Xedia's QVPN router comes with firewalls and can handle L2TP and IPSec tunneling with 56-bit-DES and tripleDES encryption.
Cabletron also announced significant VPN enhancements to its current line of SSR 100, 200 and 500 SOHO and branch office routers to support secure VPN tunneling based on IPSec and L2TP.
L2TP supports multiple, simultaneous tunnels for a single client and provides better user authentication.
Currently, MSOs typically use three boxes to deliver three different services, including deploying a cable router for commercial static IP high-speed Internet, an eMTA for commercial phone service, and a stand alone L2TP v3 router for Ethernet over DOCSIS service.
According to the company, the new software has been launched to eliminate the need to lease communications lines by allowing customers to use the L2TP protocol to send non-IP traffic via theInternet.
For instance, simple switches are not sufficient to provide advanced encapsulation such as MPLS, L2TP, GRE and Ethernet pseudo-wire and the Quality of Service (QoS) features such as shaping, policing and re-marking of IP packets needed by carriers to offer service level agreements (SLAs) with their customers.