[c-nsp] Suspect MTU Issues

[Gert Doering]

Hi,

On Wed, Jul 13, 2011 at 09:38:56AM -0400, Keegan Holley wrote:
> > You have an MTU problem.  If you want to send (1500 byte + extra header
> > bytes) packets over a link with a MTU of 1500 -> FAIL.
> >
> > It's actually going to be 1500 - header sizes.  So 1500 - MPLS (4bytes) =
> 1496  possibly - IPSEC (20 Bytes) = 1476

The input packet is 1500 bytes (+ethernet headers, not counted on IOS MTU
settings), you tack 4 byte MPLS on it -> your egress packet is 1504 
(+ethernet header).  So if your intermediate switches only allow
1500, you have a FAIL.

Which is what I said, just in more words.

gert

-- 
USENET is *not* the non-clickable part of WWW!
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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de
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