[c-nsp] Cisco IOS ping utility reports lower RTT than possible

[Martin T]

On Thu, May 2, 2019 at 11:07 AM James Bensley <jwbensley at gmail.com> wrote:
>
> On Mon, 29 Apr 2019 at 11:14, Martin T <m4rtntns at gmail.com> wrote:
> >
> > Hi,
>
> Hi Martin,
>
> > I have a following very simple network topology:
> >
> > CISCO1921[Gi0/0] <-> [eno3]svr
> >
> > Gi0/0 in Cisco 1921 ISR has 10.66.66.2/24 configured and eno3 in Linux
> > server has 10.66.66.1/24 configured. RTT on this link is 10ms:
>
> How do you know this to be 100% correct - have you OTDR/iOLM tested this link?
>
> Cheers,
> James.

Hi James,

I can't OTDR it because this delay is made with Linux netem qdisc.
However, I can compare it with for example using Juniper RPM(Cisco IP
SLA analogue): https://i.imgur.com/i8jccwh.png ..or Linux ping
utility: https://i.imgur.com/NeubqAV.png On both graphs I have plotted
21600 measurements. None of those are below 10ms.


thanks,
Martin