[c-nsp] Ping test with DF bit and MTU / IP MTU value

[Muhammad Atif Jauhar]

Yes... there is typo error in 3rd point "I am not able to ping more then
size 1520 with DF bit"

Means there is no issue in link and I will not able to ping with DF bit more
then size 1520.



On Wed, Jan 19, 2011 at 10:49 AM, Pshem Kowalczyk <pshem.k at gmail.com> wrote:

> Hi,
>
> On 19 January 2011 15:20, Muhammad Atif Jauhar <atif.jauhar at gmail.com>
> wrote:
> > Hi,
> >
> > I am testing the link and face issue.
> >                  1. while performing ping test without df bit, I am able
> to
> > ping with size upto 18024
> >                  2. while performing ping test with df bit, I am able to
> > ping with size 1520
> >                  3. while performing ping test with df bit, I am able to
> > ping with size more than 1520
> >
> > *Kindly let me know, why I am not able to ping with DF bit with size more
> > than 1520 (MTU value). How can I troubleshoot the issue. *
>
> Points 2 and 3 seem to be contradictory. Assuming that you actually
> meant that you can not ping with packets bigger then 1520 with the DF
> bit set - this is expected behaviour. The DF bit tells the routers
> that they can not fragment that packet (which they do if the DF is not
> set). As your MTU is 1520 the biggest packet with DF bit set can only
> be 1520. Anything bigger won't be forwarded.
>
> kind regards
> Pshem
>



-- 
Regards,

Muhammad Atif Jauhar
(+60-10-2155076)