Is there a way, via standard ethernet layer2 protocols, to test latency to a device without using it's IP address?


I have a fibre "box" provided by my ISP physically connected to my router via copper ethernet. The ISP gave me the IP address of the device after I asked for it in order to run latency graphing using smokeping.

Unfortunately it seems the device's IP address is not locally routable, meaning traffic to the device goes out to the ISP's core network, probably to another city, and only after that does it come back down the fibre service to the device. Instead of less than 1ms, latency to the on-site device is about 20ms. By comparison, latency to the ISP's core router in my city is about 800μs.

I do not have configuration access to the device, therefore I cannot set up a "local" IP. The ISP also refuses to add such an IP to the device - likely because it would then not conform to how all their other on-site devices are configured.

  • 2
    1) what model device is fibre unit? 2) How is your router configured to connect to it? (Might be PPPoE, but could be lots of things). – jonathanjo Mar 20 '18 at 12:48
  • 1) MikroTik RB260. 2) The router configuration is only using static routes. Though I have no way 100% to confirm, I believe the first hop is the ISP's edge router in their datacentre. – zaTricky Mar 20 '18 at 13:13
  • Unfortunately, questions about home networking and consumer-grade devices are explicitly off-topic here. You could try to ask this question on Super User. – user36472 Mar 20 '18 at 13:20
  • This is for a FTTB service - and my query is not equipment-specific. My ISP might use cheaper equipment - but this isn't a "home-networking" query. ;) – zaTricky Mar 20 '18 at 13:59
  • Unfortunately, if you cannot configure the network device, your question is off-topic here because you do not directly control it. It is explained as a caveat in the help center: "under your direct control." – Ron Maupin Mar 20 '18 at 14:34

The narrow answer is no, there's no "ethernet ping" which is normally implemented.

Your network termination unit appears to be a switch, presumably switching between your local copper and fibre ethernet; this is consistent with your description that the next-hop ISP router is down the fibre ethernet.

If the ISP has configured several of the switch ports for your local use, you can time local packets through the switch. It's basically certain that you'll find they are fast under no-load conditions.

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  • Great point re using the switch ports as a kludgy alternative. It will at least prove the device is working (and not overloaded). I'd need to check if at least one port on the device is working/available. – zaTricky Mar 20 '18 at 14:52

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