[e2e] opening multiple TCP connections getting popular

Joe Touch touch at ISI.EDU
Wed Aug 29 22:07:00 PDT 2007


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 -
> Amazingly, these guys are approaching ISPs to re-sell this product 

There have been other companies predicated on similar model - e.g.,
packeteer. The IETF doesn't do compliance verification, and doesn't
issue seals of approval.

> 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?

The issue isn't how many flows are fair. It's whether users can get
around such notions by spawning processes, opening multiple sockets, etc.

The transport layer is per-connection fair. If you want per user or per
parent process fair, you need user/process IDs (which isn't what we
have). That's not a protocol issue per se; it creeps deeply into the OS.

It also begs the question of what fairness is - and whether you'll need
biometrics to enforce this all the way to layers 8, 9, 10, 11, etc. in
the stack ;-) If you want per-login fairness, or per port group, or per
process group, you can enforce this through RFC2140-style aggregation.

It seems like you're bothered by two problems:

	1) the IETF doesn't enforce its standards in

	2) TCP fairness doesn't flow up through the OS to
	   a unit you prefer (e.g., a user)

Neither one is solvable at the transport layer.

Joe Touch                Sr. Network Engineer, USAF TSAT Space Segment
               Postel Center Director & Research Assoc. Prof., USC/ISI

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