I've been seeing a surge in complaints from customers of your ISP this past
week, and always about connection problems and download speeds. It seems
quite likely that they are throttling or "shaping" P2P right now, most likely
because traffic has been too heavy.

The gnutella network has no control mechanism like you described, and
probably never will. Such a feature would be so unpopular that a lot of people
would start rejecting updated versions of LimeWire and the other gnutella
programs just to avoid the artificial slowdown.