Pings to devices in the internal network have grown to 100-600ms. What is the reason?

Question

Computer networks

There is a network of firms. About 40 pcs. Everything worked fine. Pings to devices on the network were usually around 1ms. But now, for some unknown reason, pings have grown to ~ 100-600ms. What could be the reason? And how to fix it.
Addition: there is no ring, there are few losses (less than 5% by eye), this is not wifi

Answer 1

Solution: checked with a sniffer. It turned out that with 2 PCs there was a network scan in a wide range. When the scan was eliminated on them, the network worked normally.

Answer 2

Step by step, piece by piece. Check ALL possible nodes that are responsible for transmitting traffic. Any switch, router, switch. Watching the pings with sadness will not solve the problem.

Answer 3

wifi? ring? losses?

Answer 4

This may be due to a hash collision on the switch, in such a situation the traffic of colliding ports starts to be broadcast on all ports and vice versa, which leads to high network load and frequent frame collisions, hence transmission delays. All switches are affected by this problem, but some have a much higher chance of a collision. Here, for example, is a description of the problem and solutions from Juniper:
https://kb.juniper.net/InfoCenter/index?page=conte...
Or just for some reason a lot of traffic is generated.
Look at the traffic statistics on the switch ports, find the ports with the largest incoming and outgoing traffic, then use a sniffer to see what kind of traffic it is - if they really generate this traffic - cut the traffic for them or knock on the cap if traffic that should not fly there flies - then it is treated by prescribing any other MAC address on a card plugged into the port or by replacing the switch.