Network periodically locks up and no patern

[rhauk68]

I am an all HP/Aruba house. 5406 core and then various other switches throughout the network alond with several AP to bridge connections.

For some time now we have had issues with the network freezing or locking up causing pretty much every 100MB piece of equipment to fail. For instance our PBX dialers will stop working and lose connection to the phone system, kitchen Epson reciept printers stop printing and a host of other issues.

This is obviously a traffic issue but not consistant. 

I am looking for advice on how to track down where the traffic is coming from as this is a major issue for revenues. Also any ideas as to why this just happens from time to time no pattern really. When it does happen it sometimes is for 20 minutes or so then other times hours.

I really need to get to the bottom of this so any help would be greatly appreciated.