OK, scenario: apartment building, 4 floors, around 100 apartments. One network fiber T into building through router into switch and then off to 4 other switches one on each foor in own dedicated data room. Each floor has a computer room for tenants to use internet. Older folks apartments BTW. Throughout the day internet drops at random times affecting the rental office and maint man and other tenants. Chasing the problem we had the ISP swap the adtran (didn't help) swapped out the router after the adtran (didn't help), swapped out the switch on floor 2 (didn't help). What's next? We were thinking of installing a PC with network traffic software to see if something is causing the intermittent drops. Do you think there is an infected PC on the network causing it? The tenants are wide open as is the PC room. Next step? Suggestions? Thanks!

That has to be a wide building. Is everything wired? If any of it's wireless, that's the problem How do you know when a politician is lying? His mouth is moving.