Re: [OSL | CCIE_Security] GRE Fundamentals

Hello TL,Here are a couple links I think are useful. It is also important
to note that a GRE tunnel interface status is only local significant on a
router. As long as the tunnel interface has viable source and destination
info, the router will mark the tunnel as up. The formation of the tunnel is
stateless which is my guess as to why you don't see a lot of information
about how a GRE tunnel is formed from an router to router communication
perspective.

http://en.wikipedia.org/wiki/Generic_Routing_Encapsulation
http://www.faqs.org/rfcs/rfc2784.html

I hope this info is useful.
Regards,
Roger

On Thu, Oct 8, 2009 at 10:09 PM, TL <tarun.ccie_at_gmail.com> wrote:

> Hi there,
>
> Is there a document/video that explains the working of GRE in detail. The
> different steps that happen when a packet destined for the GRE tunnel is
> created to the stage when it reaches it's destination.
>
> I read the RFP 1701, 1702 on GRE but that does not goes into this detail,
> neither did I find it in any other text.
>
> Can someone please provide some pointers as I feel deep understanding of
> GRE is very important for VPN/DMVPN stuff.
>
> Regards,
> TL
>
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Received on Thu Oct 08 2009 - 22:38:27 ART