[Cake] best way at getting at tcp ack data?

[Noah Causin]

After reading about ACK filtering, I have an idea and wonder if it is 
possible.  I only have basic knowledge about the TCP protocol.

Instead of dropping TCP data packets, would it be possible to drop 
normal ACK packets to signal congestion?

The sender would see that ACK packets are missing and slow down its 
transmission rate and re-transmit the data packets it thought were 
lost.  Since the client has already received the packets beforehand, the 
application would not experience packet loss, and TCP would simply 
re-acknowledge the packets and discard the copies.

Could this be used to create a pseudo-lossless congestion notification 
scheme, since the client would not see any packet loss, which could be 
beneficial for certain applications?

Noah