Comcast blocking p2p uploads

Fri Oct 19 21:01:56 UTC 2007

Steven M. Bellovin wrote:
> Personally, I see a big difference between rate-shaping and sending
> RSTs.  (I suppose you could view RSTs as allocating 0 bps, but that's
> not a helpful distinction.)
>   
I see a big difference as well. 

With rate-shaping they would need to have the P2P identification widget 
in-line with the data path to be able to classify and mark traffic so 
that it can be queued/throttled appropriately.  This means that overall 
network availability would now be tied to a device that isn't really a 
proven piece of network hardware.  To send TCP resets, on the other 
hand, all that is needed is a span session to the inspection probe to 
let it determine which connections to shutdown and issue the resets 
completely out of band.  If the inspection probe kacks, everything on 
the network continues to function and only the P2P throttling 
functionality would be impacted.

As a network engineer focused on availability, I have a very clear 
preference in implementation.

-Eric