Ping times change over time only to a certain server

Question

The problem happens only to a certain server from a nearby country. When i test the ping to that server, i get 30-40 ms today, then tomorrow i'll get 240-250 ms. Sometimes, an hour later it'll be 50-60 ms and then later gets higher or maybe lower (The response times are stable, so it's most likely not due to a congested link). I use the same ip to test the server and my connection is perfectly fine. This problem happens only to this certain server or the ISP itself. I tried tracert, but nothing seems out of ordinary (The forward path doesn't indicate any issues, only after entering the very first hop of this particular ISP backbone of the server. I would assume it has something to do with the reverse path but i'm not sure). It's a permanent issue, but not really much of an issue. It's quite baffling seeing how ping times change occasionally from time to time and never sticks to a specific number like any other servers. I don't understand. Can anyone please explain to me why the traffic time changes or rather, the routing table changes here and there?

Answer 1

In the internet different pieces of WAN are connected together, but their connection path isn't constant. Links come up and down, network outages occur, network load changes - this results in the dynamis protocol changes, which ISP interexchange. And this is the most possible reason of the icmp latency changes. Using two traceroute outputs - one taken while latency is minimal, and one taken when latency is at its maximum, you can determine what routing changes happen or, and, regardless of the fact is the hop list changing or not, what hop (or sequence of hops) is adding the most delay. However, if you are not connected with two or more ISP via BGP routing protocol, little can be done to influence on that.