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 ?
By embedding IPSec and L2TP into its CN1050 range of secure wireless LAN routers, Colubris Networks extends the protection of VPN to wireless traffic.
With our CN1050, wireless client stations will have to establish an IPSec tunnel or an IPSec-protected L2TP tunnel to gain access to the network.
For ISPs targeting the business-to-consumer marketplace, private label L2TP expands their service area footprints in a cost-effective manner.
With the growth of the business-to-employee and advertiser-supported ISP business models, AT&T's new private label L2TP offering allows the Internet Service Distributors who serve these market segments to strengthen their relationships with the advertisers, corporations and affinity groups that subsidize monthly access fees.
Interoperable L2TP over IPsec implementations with five companies;
Similar to AT&T's L2TP service, it allows customers to use the public Internet to access private network resources using multiple transport protocols, such as Novell's Internetwork Packet Exchange (IPX) and NETBIOS.
With L2TP Tunnel Navigation, a capability unique to the Nortel Networks' CVX 1800 modem wholesaling solution, tunnels are selectively assigned between a network of CVX 1800 shelves to specific Shasta 5000 BSNs based on each Shasta 5000's subscriber capacity.
In addition to performance testing, IxAccess can be combined with Ixia's IxANVL(TM) (Automated Network Validation Library), offering the industry standard in conformance testing with the IxANVL PPP and L2TP suites.
1X wired Ethernet port security that protects against unauthorized network access through APs installed in public areas, * Configurable timeouts for idle clients that help increase network capacity, and re-authentication grace periods that eliminate users from having to constantly re-authenticate, * Wireless Internet Service Provider roaming (WISPr) and L2TP tunneling support on standalone ZoneFlex 802.
This guide for network support engineers and architects covers a range of VPN technologies, including IPSec, MPLS, L2TP versions 2 and 3, PPTP, and L2F.
With eight self-contained chapters organized and designed to facilitate rapid and straightforward troubleshooting, Troubleshooting Virtual Private Networks provides detailed information on addressing all common and not-so-common issues associated with IPSec VPNs, MPLS Layer-3 VPNs, any transport over MPLS (AToM)-based Layer-2 VPNs, L2TP Version 3 (L2TPv3)-based Layer-2 VPNs, L2TP Version 2 (L2TPv2) VPNs, PPTP VPNs, and L2F VPNs.