[e2e] [SPAM] opening multiple TCP connections getting popular

David P. Reed dpreed at reed.com
Wed Aug 29 11:09:41 PDT 2007


It's worth pointing out that this is nothing new.   So-called 
download-accelerators that do exactly that have been around for at least 
5 years now, and are extensively used  on Windows platforms, because 
they work as advertised.   I think the one I used to use on Windows was 
called "Lightning Download" and it was freeware.

But a deeper question is this: if I want a movie each day, and my daily 
average rate of consumption is not going to change because I can't watch 
movies faster than my eyeballs work, why is this going to be a big 
problem?   Is there any evidence of people downloading movies that they 
don't watch?

The mitzvah gained from shorter latencies allows other people to 
download at their convenience with out me competing with them.

In fact, isn't dragging one's download out just maximizing all the users 
wait time?

Maybe the sky isn't falling?

Bob Briscoe wrote:
> e2e-interest folks,
>
> This product is being very aggressively marketed:
> <http://www.speedbit.com/video%5Faccelerator/>
> It opens 10 HTTP/TCP connections to accelerate video downloads - 
> essentially using the well-known broken feature of TCP (see the I-D 
> below) to enable one user to compete more aggressively for the same 
> bandwidth against other users. But it flies below the limit of 10 
> concurrent half open connections added to Windows XP SP2 - claimed to 
> be added to slow down worms but also limiting p2p filesharing clients.
>
> Amazingly, these guys are approaching ISPs to re-sell this product - 
> so their customers will just be competing more aggressively with each 
> other and largely end up back where they started. It's worth reading 
> the Business Week article linked off the above page to see just how 
> convincingly this is being marketed - They fooled the technology 
> assessment people in at least one large ISP (mentioning no names).
>
> If you're tempted to poke fun at all these people because they clearly 
> don't understand, I actually think we should be chastened ourselves. 
> Why shouldn't app-layer people expect the transport layer to correctly 
> handle fairness?
>
> To quote the Internet Draft "Flow Rate Fairness: Dismantling a Religion"
> <http://www.ietf.org/internet-drafts/draft-briscoe-tsvarea-fair-02.pdf>
> "...flow rate fairness isn't even capable of reasoning about questions 
> like, "How many flows is it fair to start between two endpoints? ...
> ...there will certainly be no solution until the networking community 
> gets its head out of the sand and understands how unrealistic its view 
> is; and how important this issue is--a conflict between the vested 
> interests of real businesses and real people."
>
> King Cnut commanded the tide not to wash over him sitting on his 
> throne on the English beach, but at least when the experiment failed 
> he humbly accepted he was subject to greater powers, never wearing his 
> crown again. I'm worrying away at the IETF to work on a proper 
> solution to the TCP-fairness problem, rather than merely issuing the 
> decree that RFC2616 HTTP/1.1 clients should observe a 2 connection 
> limit to each server.
>
>
> Bob
>
>
> ____________________________________________________________________________ 
>
> Bob Briscoe, <bob.briscoe at bt.com>      Networks Research Centre, BT 
> Research
> B54/77 Adastral Park,Martlesham Heath,Ipswich,IP5 3RE,UK.    +44 1473 
> 645196
>
>


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