From: Scott M Vermillion (scott_ccie_list@it-ag.com)
Date: Fri Mar 13 2009 - 03:38:37 ARST
Yes, but it also came in from the other Scott that GRE is only 8 bytes
of overhead when a tunnel key (not to be confused with IPSec or the
like) is in use. ;-) For example, in certain DMVPN scenarios you
need a tunnel key configured so that a hub can demux different DMVPNs
terminating to a single loopback. Normally GRE will only be 4 bytes
of overhead, as was demonstrated by Mr. Kutchin's testing...
On Mar 8, 2009, at 12:22 , Daniel Kutchin wrote:
> Was wondering how to demonstrate the diff in packet sizes using ping.
>
>
>
> Pinging an IPv6/GRE/IP tunnel used packet lengths of 124:
>
>
> *Mar 1 01:40:41.202: IP: s=10.10.10.10 (Tunnel12), d=10.20.20.20
> (Ethernet0/0.12), len 124, sending, proto=47 <-- GRE
> ^^^^^^^
>
>
>
> Whereas an IPv6/IP tunnel used ping packet sizes of 120:
>
>
> *Mar 1 02:56:28.296: IP: s=10.10.10.10 (Tunnel12), d=10.20.20.20
> (Ethernet0/0.12), len 120, sending, proto=41 <-- IPv6IP
> ^^^^^^^
>
>
> I obtained a packet size difference of 4 not 8 ..
On Mar 12, 2009, at 6:43 , libone mhlanga wrote:
> This came in from Scott the other day :-
>
> IPv6IP you have a 40-byte IPv6 header + 20-byte IP header
>
> GRE you have a 40-byte IPv6 header + 8 byte GRE header + 20 byte IP
> header
>
> ---------[ Received Mail Content ]----------
>
> Subject : IPV6 tunnel overheads
>
> Date : Thu, 12 Mar 2009 17:25:56 +0530
>
> From : GAURAV MADAN <gauravmadan1177@gmail.com>
>
> To : GS CCIE-Lab <ccielab@groupstudy.com>
>
> Hi Group
>
> Can someone summarize abt the overheads assosiated with IPV6 tunn
> types
>
> I found the discussion some days back when GRE was compred with IPV6IP
>
> As of what I know ; GRE adds 8 byte more (adds its own header) ..
>
> This I am asking to tackle question that say ; use type which has
> least
>
> overhead etc etc
>
> Gaurav Madan
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
>
> Subscription information may be found at:
>
> http://www.groupstudy.com/list/CCIELab.html
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
Blogs and organic groups at http://www.ccie.net
This archive was generated by hypermail 2.1.4 : Mon Apr 06 2009 - 06:44:04 ART