As P2PNet observes, many ISPs recently began shaping their network traffic to keep BitTorrent users from sucking up all of the available bandwidth -- in some cases, BitTorrent accounts for half of an ISP's traffic. However, BT users were quick to work around the ISP's detection schemes by using RC4 encryption. All of the major BitTorrent clients recently added the option to encode transfer files using RC4 encryption.
The NetEnforcer uses Allot's deep packet inspection technology "to identify and analyze hundreds of applications and protocols, track subscriber behavior, prioritize traffic and shape traffic flows."
Have you been throttled?