Unanswered Question
Jul 27th, 2012
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Hi all,

Can anyone clearly explain that what is the difference between L2TP and GRE tunnel?

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


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soroushm Fri, 07/27/2012 - 07:42
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Hi Murat

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.

Hope it Helps,



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