FastTCP Commercialized Into An FTP Appliance 156
prostoalex writes "FastTCP technology, developed by researchers at CalTech, is being commercialized. A company called FastSoft has introduced a hardware appliance that delivers 15x-20x faster FTP transmissions than those delivered via regular TCP. Says eWeek: 'The algorithm implemented in the Aria appliance senses congestion by continuously measuring the round-trip time for the TCP acknowledgment and then monitoring how that measurement changes from moment to moment.'"
FastTCP is just a fancy name for TCP Vegas? (Score:5, Informative)
Powered by handwavium (Score:3, Informative)
Re:hmm (Score:4, Informative)
Hype (Score:4, Informative)
Other possibility is some sort of header compression.
Anyway, to use this safely you'd need to be *sure* you know your link charasteristics. The reason TCP has the slow-start mechanisms in the first place is to make sure you don't overflow the link - that's why it's known as flow control
Re:hmm (Score:5, Informative)
Re:Powered by handwavium (Score:5, Informative)
http://netlab.caltech.edu/FAST/ [caltech.edu]
Several highlights include:
- Caltech held the world record for data transfer for awhile
- Won the bandwidth challenge at SC05
It's one of the best ways to tune a single TCP stream. Finally, the list of about 50 TCP-related publications should indicate this isn't handwavium:
http://netlab.caltech.edu/FAST/fastpub.html [caltech.edu]
Traditional TCP streams (such as what you get with FTP) top out around 10-20 Mbps. If you want to see a single stream go a couple hundred Mbps, you need TCP tweaks like FAST (however, FAST is one of many competing TCP "fixes").
Re:To gain that much speed... (Score:3, Informative)
"The Aria 2000, which is due in July, supports 1G-bps links. Existing Aria appliances support 10M-bps links, 50M-bps links and 200M-bps links."
10gbps my ass. The one they haven't released only does a tenth of that. And the smallest of their products barely handles my home cable line.
For what it's worth, my initial thought was that they must be targetted truly massive lines and that it would be a lot harder to truly use those. Too bad it wasn't true.
Re:Hype (Score:3, Informative)
ftp://ftp.rfc-editor.org/in-notes/rfc3649.txt [rfc-editor.org]
ftp://ftp.rfc-editor.org/in-notes/rfc3742.txt [rfc-editor.org]
I guess this device works as some sort of wrapper so that legacy TCP implementations don't get slowdowns, but doesn't strike as anything revolutionary to me - the RFCs are from year 2003.
Re:No Way (Score:3, Informative)
Re:FastTCP is just a fancy name for TCP Vegas? (Score:3, Informative)
Those who fail to understand TCP.. (Score:3, Informative)
TCP is the most researched most tweaked and most examined reliable transport protocol, and trying to reinvent your own over an unreliable protocol is asking for trouble.
Re:No Way (Score:2, Informative)
Uhm, let me guess, your knowledge of TCP is based on Trumpet Winsock for Windows 3.11 ?
Modern tcp-stacks most certainly scale the window and certainly don't "mis-interpret" high latency as congestion. (they do however interpret high packet-loss as congestion, which is a reasonable guesstimate most of the time, but *DOES* break down on links that, for example, have a constant packet-loss of a few percent (regardless of traffic-levels)
Congestion Control (Score:5, Informative)
If you use Linux, have (CU)BIC loaded, correctly setup your NIC, and tune your TCP settings (rx/tx mem, queuelen, and such) then there is be no way for FastSoft to claim a 15-20x speedup improvement. I've done full 10 gigabit transmissions with a 150ms RTT using that kind of setup. FastSoft's device doesn't even support 10 gigabit, and their 1 gigabit device still isn't released.
This article is nothing other than a Slashadvertisment.
TCP is underestimated... (Score:3, Informative)
When something with as much high-profile support as IPMI ends up with such shortcomings, it goes to show that people easily fail to understand why this aspect or that of TCP is not applicable to their use.
As to TCP over UDP, that's an example of a very bad sounding ideas. Redundant features of TCP and UDP. It's not as bad as TCP over IP over PPP over SSH which is over TCP (multiple reliable protocols on top of each other), but still, if you wanted to be a better TCP than TCP, the place to implement would be at the same layer, on top of IP protocol, not on top of UDP.
Re:So where's the SlowTCP? (Score:3, Informative)
If you're looking for QoS in a home environment, the easiest solution is likely to replace your router with one capable of running DD-WRT. (This assumes you have a "consumer grade" router. If your gateway to the outside world is a normal PC running Linux, it's just a matter of setting up QoS on that box... Quite a few HOWTOs exist for this.)
Re:hmm (Score:4, Informative)
And I mean that: next time you implement one of these so-called miracle devices, run a TCP dump from both ends. If the TCP syn cookie is different, DO NOT INSTALL IT, AND RETURN THE DEVICE IMMEDIATELY.
Don't say someone didn't warn you.
I've spent the last four to six months debugging peoples' networks where it has invariably come down to these WAN-accelerators getting in the way and mangling network traffic.
*VERY* poorly implemented, to a one!
Re:No Way (Score:5, Informative)
Well, let's see. They won the 2005 supercomputing bandwidth challenge with their system. They also have numerous publications in peer-reviewed journals, invited presentations at conferences, etc. Sure doesn't sound like snake oil.
The more things change... (Score:3, Informative)
"Many very stupid companies have tried to come up with overly clever ways to speed up TCP/IP. TCP, by its nature, is a stateful and bidirectional protocol that requires all data packets to be acknowledged; this makes the data flow reliable, by providing a mechanism for dropped packets to be retransmitted; but this also makes for a more strictly regimented flow structure involving more packets transmitted over the wire than in simpler, non-reliable protocols like UDP-- and therefore it's slower. One company that thought itself a lot smarter than it really was, called RunTCP, came up with the idea of "pre-acking" TCP packets; it would send out the acknowledgments for a whole pile of data packets in advance, thus freeing them from the onerous necessity of double-checking that each packet actually got there properly. And it worked great, speeding up TCP flows by a significant margin-- in the lab, under ideal test conditions. The minute you put RunTCP's products out onto the real Internet, everything stopped working. Which stands to reason-- their "solution" was to tear out all the infrastructure that made TCP work reliably, under competing load and in adverse conditions, in the first place. Dumbasses."
Re:No Way (Score:3, Informative)