Investigating ping latency

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Usually in a LAN I get smth like :

Reply from 192.168.1.1: bytes=32 time<1ms TTL=64

with the occasional 10ms. But today on a friend's home I found 32ms consistently when pinging the router.

The structure is very simple:
router - non manageable switch - patch panel - 20m cat5e in walls - wall socket - patch cord - lap top

First question : What are the possible causes for latency over 2-3ms on a simple network ?

  • Damaged cables/patch cords
  • Bad socket/patch panel connections
  • Interference from electrical cables - shouldn't it rather cause dropped packets
  • Busy network - this could be excluded though because usually intermittent
  • Router firmware bug
  • Computer Firewall
  • Mismatching NIC configuration
  • IP conflicts

Second question : What should I look for in this specific case ?

The same lap top pings at 1ms on my network, and speed & duplex is set to auto negotiation on NIC. I will connect directly to the router to check it and there is nothing else on the network to overload it. I will check other lines/wall sockets, but is this something that can be related to the physical wires ?

alfred

Posted 2019-07-31T12:31:36.180

Reputation: 363

First question: Most of the stuff listed. – DavidPostill – 2019-07-31T12:46:57.167

3Second question. Connect laptop to router. Test. Connect at next furthest point. Test. Repeat. – DavidPostill – 2019-07-31T12:48:39.353

Answers

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In order to discover where is the issue you can try to connect your laptop and do the ping test from the following positions (marked with an "X")

router - X - non manageable switch - X - patch panel - 20m cat5e in walls - wall socket - X - patch cord - lap top

Then compare the latencies at those points and you cna have an approximation about where the problem is.

Zumo de Vidrio

Posted 2019-07-31T12:31:36.180

Reputation: 310

I am also interested on the theory of this. So, can physical wire connections cause latency ? And what about electrical interference. – alfred – 2019-07-31T13:07:34.103

Never heard about physical connectors by themselves causing latency. Of course the wire can, as longer it is more latency. I have more suspects from the point of view of the intermediate devices. – Zumo de Vidrio – 2019-07-31T13:36:42.783

Asked: 2019-07-31T12:31:36.180

Viewed: 33 times

Active: 2019-07-31T13:05:03.943