I don't know, I had some connection issues at home (my connection is way worse, like 20/2Mbps adsl) with 2 rigs, I guess they collapsed the upload so I don't want to suffer the same problem with 20 rigs, or at least I want to know how much would be my internet connection expenses. Also, I don't know if this mining programs establish a lot of connections like a p2p program, because that behaviour kills connections easily, not like a bandwith problem, in the case of multiple p2p programs I think is more about the router being unable of attending hundreds or thousands of connections.