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Can anyone clearly explain that what is the difference between L2TP and GRE tunnel?
Is L2TPv3 Any different

I am trying to understand where these protocol are used and why we use L2TP instead of GRE in some cases and vice versa.

Thanks

Terminator
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2 Answers2

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L2tp and GRE are totally diffrent protocols

GRE is a simple IP packet encapsulation protocol. a GRE tunnel is used when packets need to be sent from one network to another, without being parsed or treated like IP packets by any intervening routers. a GRE tunnel interface comes up as soon as it is configured and it stays up as long as there is a valid tunnel source address or interface which is up.

L2TP is a tunneling protocol (used to support VPNs) that allows multiplexing of multiple PPP sessions between two IP-connected endpoints, and a control protocol for dynamically establishing and maintaining the emulation of these PPP sessions. This is very different than GRE.

Mr.lock
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  • Please give credit where credit is due. This answer is just a C/P from [here](https://community.cisco.com/t5/routing/l2tp-vs-gre/m-p/1981308/highlight/true#M194939) (even with "a GRE tunnel ..." instead of capital "A"). – dmnc Mar 16 '21 at 23:26
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L2tp is primarily for vpn it is a combination of pptp and cisco's l2f or layer 2 forwarding.

GRE is cisco's generic route epcapsulation basically creating an ip tunnel to carry "other" traffic accross an ip backbone. it must be terminated on the outside or closet points of the tunnel.

Malikyu
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