i am running a small ISP of 3M.i have a bandwidth manager.i have tried btest throughput on my backhauls i am getting 3 to 4 Mbps.
the problems is am getting slow internet sometimes the browser keep saying server not found.i have asked my providers about the bandwidth quality they say its ok.they have shown me graphs that am using about 2.8M.the slow connection can it be that because am almost using my whole bandwidth?.
Cause my Provider has kept on saying i must check my backhauls which are fine.

need help.
thanks

Yes, of course you would experience slow browsing if you're using all your WAN bandwidth.

Probably because you use all your bandwidth. Usually upload speed is much lower than download and when you reach your download limit, you would probably have reached the upload speed long before then. This will kill your download speed and pings. Having the symptoms described.

thanks guys.but practical how many 128k ,256k and 512k can one connect on 3M

That is sort of impossible to answer, isn't it? It depends on what kind of oversubscription ratio you're comfortable with selling, and what exact mixture of plans you have, and what kind of usage patterns there are. I wouldn't feel comfortable at more than 15:1, which means you could try and sell 45Mbps if you have 3Mbps available. That will, however, not work out well at all if you have customers that all go online in the evening around the same time.

Just to add to what Fewi said. Another one to watch out for is uncap lines, especially if you get uncap users downloading 24/7 of which you will always get some.