How does RTT is determined?



  • Hello,

    We have a "flaky" DSL connection (one out three). The connection is getting high RTT values and the ISP says that is PFSense fault. I have the Google DNS as alternative monitor IPs.

    Best regards

    Kostas



  • I think that is calculated from ping (specifically apinger service). If you remove pfsense, do you still have high ping times?
    My ISP wanted to blame my pfsense also. I would not let them and showed them that with a direct connection it was still very high latency. Turns out they knew I was behind an oversubscribed system and they would need to replace or add additional HW. Which, they have said they are working on, but it is still bad after 3 months.



  • Well, they came today and tested the line in all hops before pfsense, using hardware equipment. They claim the line is fine (and, as per the device measurements, it is).

    For now, the line is stable.

    Best

    Kostas



  • Question is, did they come at peak time or off peak time? generally an overloaded system is fine when there is not much load on it. I sent the quality graph from my RRD for the WAN line and proved it to them.



  • They came in peak time, and they stressed up the line. I will monitor the line today and get back.

    Kostas



  • In one of the three WANs, I changed the alternate monitor IP from 8.8.8.8 to the secondary DNS of the ISP, and RTT get from 108 ms to 36 ms.

    Is this measure unreliable?

    Best

    Kostas



  • The google DNA server is probably further away than your ISP DNA is. It is probably a better measure of your of your line IMO.



  • Thank you!

    The google DNS is a better measure or the ISP one?

    Kostas



  • I would use isp gateway or dns.



  • Thank you!

    I will leave it as is then (with the ISPs DNS).

    Best regards

    Kostas


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