[freenet-dev] Packet size proposal

[Matthew Toseland]

On Monday 10 March 2008 21:55, Michael Rogers wrote:
> Matthew Toseland wrote:
> > Sure. But it will cost them. RSTs are trivial. The Golden Shield uses RSTs 
for 
> > example, rather than remembering which streams it wants to kill. Because 
> > statefully killing streams would cost many times more.
> 
> Killing, yes, but if they just want to shape the traffic then RED is 
> cheap and stateless. I don't know why Comcast has decided to use RSTs 
> instead of traffic shaping, but sooner or later they'll have to move to 
> traffic shaping as more P2P traffic is encrypted.
> 
> > Throttling UDP 
> > likewise would cause other problems: it would slow down skype 
dramatically, 
> > alienating a lot of users, so they'd need to put more hardware in to 
detect 
> > skype...
> 
> I'm not sure about that - reducing VoIP traffic is the second major 
> selling point for these devices after reducing P2P traffic. :-)

Resulting in a mass exodus of users, surely? Well I suppose we're talking 
about monopoly providers here, so maybe not...
> 
> > Classic STUNT is far more complex than UDP traversal, requires listening 
on 
> > raw sockets (i.e. needs root), and requires using a globally reachable 
STUNT 
> > server, which is required to send a spoofed SYNACK to each side!
> 
> STUNT has moved beyond that technique, I believe these days they're 
> using simultaneous open and port prediction, both of which can be 
> coordinated by a third peer so you don't need any dedicated servers or 
> spoofing - it's similar to UDP hole-punching but with tighter timing.

But you absolutely must have a third peer. Whereas with UDP, if both sides 
know the other's address, you can just connect. This greatly improves 
connectivity in practice imho.
> 
> Cheers,
> Michael
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