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

[Octavio Alvarez]

On 5/2/19 10:11 AM, Martin T wrote:
>>> 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?
>>
> 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.

Hi,

I am curious about what do you see if you placed a two-card laptop in
the middle as a bridge, do a tcpdump capture on the server-facing NIC
and analyze the times with Wireshark.

Best regards,
Octavio.