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In the News (Sun 26 May 19)

 [No title]
FAST FAST TCP for High-Speed Long-Distance Networks [Page 2] draft-jwl-tcp-fast-01.txt July 2003 The second source of oscillation is due to instability at the flow level, and can be reduced only with accurate estimation of congestion measure and a stable design of the flow dynamics.
FAST FAST TCP for High-Speed Long-Distance Networks [Page 4] draft-jwl-tcp-fast-01.txt July 2003 If pacing of packet transmission is unavailable, the implementation should increment or decrement the congestion window smoothly over one RTT to the new target window w_new.
The alpha parameter in FAST TCP determines both the equilibrium bandwidth share and the aggressiveness during the additive increase phase when queueing delay is zero.
www.faqs.org /ftp/internet-drafts/draft-jin-wei-low-tcp-fast-01.txt   (2618 words)

 [No title]   (Site not responding. Last check: 2007-10-08)
Reno TCP adds fast recovery to Tahoe TCP along with header prediction and delayed ACK (receivers implementing delayed ACK must acknowledge the receipt of at least every other packet and no later than 200ms after the receipt of a packet), and was first implemented in 4.3 BSD Reno in 1990.
Fast recovery operates under the assumption that each dup ACK received represents a single packet having left the pipe.
The reason for this is that the receiver’s advertised window may suddenly increase upon leaving fast recovery; if the sender had been prevented by the receiver’s advertised window from sending packets during fast recovery, then, without “maxburst”, it is possible for the sender to send a large burst of packets upon exiting fast recovery.
www.cs.berkeley.edu /~kwei/readings/TCP/summaries/Tahoe_Reno_Sack.doc   (924 words)

 FAST TCP - Wikipedia, the free encyclopedia
FAST TCP is a variant of TCP networking protocol, developed at the California Institute of Technology, with a congestion control algorithm especially targeted at high-speed, long-distance links.
The difference between TCP Vegas and FAST TCP lies in the way in which the rate is adjusted when the number of packets stored is too small or large.
FAST TCP makes larger steps when the system is further from equilibrium and smaller steps near equilibrium.
en.wikipedia.org /wiki/FAST_TCP   (721 words)

 SSF TCP Regression Tests   (Site not responding. Last check: 2007-10-08)
TCP Reno: Fast recovery with a single packet drop and maximum congestion window is limited.
TCP Reno: Fast recovery with two packet drops and maximum congestion window is limited.
TCP Reno: Fast recovery with two packet drops and delayed-ack, comparing the trace with and without maximum congestion window limit.
www.ssfnet.org /Exchange/tcp/tcpTestPage.html   (817 words)

 SPACE.com -- Pushing the Speed Limit: For Researchers, the Internet Just Got Faster
For now, however, FAST researchers stressed the fact that that their system is only a prototype, with only a small amount of network traffic sharing the transmitted files.
But while the FAST protocol may help put reams and reams of electronic research at the fingertips of researchers, the impact on personal computer users, who rarely feel the urge to access data from the VLBI or a particle accelerator, may be less apparent.
FAST researchers also added that while the new protocol would be a boon to scientists, it could mean more woes for the entertainment industry plagued by computer piracy since faster transfer speeds could also allow faster bootlegging.
www.space.com /businesstechnology/technology/fast_protocol_030409.html   (1181 words)

 Packet tracking promises ultrafast internet - 05 June 2003 - New Scientist
A key feature of Fast TCP is that it could run on the same internet infrastructure we have today.
TCP breaks down large files into small packets of about 1500 bytes, each carrying the address of the sender and the recipient.
By ganging 10 Fast TCP systems together, the researchers have achieved transmission speeds of over 8.6 gigabits per second, which is more than 6000 times the capacity of ordinary broadband links.
www.newscientist.com /article.ns?id=dn3799   (601 words)

 TCP Stack Measurements on Lighly Loaded Testbeds
FAST TCP is based on Vegas and uses the RTT to indicate congestion.
The FAST TCP stack appears to take longer or closer to 8 seconds as can be seen below from the iperf -i (interval) option output: After slow start the throughput appears to remain fairly steady at between 840Mbits/s and 1Gbits/s.
To ensure that the throughput was not limiuted by TCP or lower levels, we also measured TCP throughput with iperf with a 32MByte requested window, a txqueuelen of 100, and an MTU of 9000Bytes.
www-iepm.slac.stanford.edu /monitoring/bulk/fast   (4743 words)

 A step toward realistic evaluation of high-speed TCP protocols
These background flows are generated by TCP and their transmission rates are elastic to the amount of traffic in the network to the extent limited by the maximum allowed by 64KB receiver buffer size.
The reason for this result could be that since FAST is delay-based, background traffic introduced more dynamics and fluctuations in the bottleneck queue and made it more difficult for FAST flows to estimate their fair shares of bandwidth based on delay information.
FAST shows very stable behavior without background traffic and the throughput values of the two flows are close enough without background traffic.
www.csc.ncsu.edu /faculty/rhee/export/bitcp/asteppaper.htm   (6979 words)

 March 19, 2003 - Caltech computer scientists develop FAST protocol to speed up Internet
The FAST results show that the high degree of transparency and performance of networks, assumed implicitly by Grid systems, can be achieved in practice.
TCP sustained an average throughput of 925 Mbps and an efficiency of 95 percent, a 3.5-times improvement, under the same experimental condition.
Caltech's FAST protocol shows that the high degree of transparency and performance of networks, assumed implicitly by Grid systems, can be achieved in practice.
www.interactions.org /cms/?pid=1000786   (1463 words)

 RFC 2582 (rfc2582) - The NewReno Modification to TCP's Fast Recovery Algor
The Fast Retransmit and Fast Recovery algorithms in NewReno The standard implementation of the Fast Retransmit and Fast Recovery algorithms is given in [RFC2581].
The modification defines a "Fast Recovery procedure" that begins when three duplicate ACKs are received and ends when either a retransmission timeout occurs or an ACK arrives that acknowledges all of the data up to and including the data that was outstanding when the Fast Recovery procedure began.
The TCP data sender is unable to distinguish between a duplicate acknowledgement that results from a lost or delayed data packet, and a duplicate acknowledgement that results from the sender's retransmission of a data packet that had already been received at the TCP data receiver.
www.faqs.org /rfcs/rfc2582.html   (3323 words)

 TCP and Successive Fast Retransmits
Given current TCP implementations, for a TCP connection with a large congestion window and multiple nonconsecutive packet drops within one window of data, it is possible for the TCP source to execute the Fast Retransmit procedure twice for one window of packets.
One fix to the problem of multiple Fast Retransmits is not to treat duplicate ACKs that acknowledge packets from the same window as packets from a previous Fast Retransmit as an indication of continued congestion.
In the Tahoe TCP implementation in our simulator, the fix was done using an extra variable high_seq to record the highest sequence number outstanding when the TCP initiated a Fast Retransmit or responded to an ECN or a retransmit timer timeĀ­out.
www.opalsoft.net /qos/TCP-80.htm   (605 words)

 TCP congestion avoidance algorithm - Wikipedia, the free encyclopedia
With TCP Vegas, timeouts were set and round-trip delays were measured for every packet in the transmit buffer.
During fast recovery, for every duplicate ACK that is returned to TCP New Reno, a duplicate unacknowledged packet from the front of the transmit buffer is sent.
TCP Hybla aims to eliminate penalization of TCP connections that incorporate a high-latency terrestrial or satellite radio link, due to their longer round trip times.
en.wikipedia.org /wiki/TCP_congestion_avoidance_algorithm   (779 words)

 broadband help » News » The Birth of 'Fast TCP' - Caltech researchers offer '8.6 gigabits per second'
Assuming this does catch on 20 or 30 years from now to say fast tcp will be reffering to an old technology that is slow and good only for reminiscing.
Although TCP is not very good at handling dropped packets, and slows down, basic TCP *DOES* try to stream data packets as fast as possible, using close to the maximum bandwidth of the weakest link.
FAST is a project sponsored primarily by the international high energy physics community (HENP) to attempt to develop a way to share massive amounts of data between widely physically separated locations at very high speed.
www.dslreports.com /shownews/28987   (2985 words)

 broadband help » News » Fast TCP story update -
Ok I don't even have to look at the caltech papers to know that the "fast TCP" story being repeated in the news wires is being misrepresented, or, at least, not understood (by reporters) and therefore by readers.
The way TCP works now is not optimal, since it was designed long ago on networks that were rather buggy and full of errors.
What I understand of Fast TCP is that the only changes will be made at the Transport layer.
www.broadbandreports.com /shownews/28996   (1079 words)

 FAST TCP simulator module for ns-2 - CUBINlab - Department of Electrical and Electronic Engineering - University of ...
FAST-TCP is a new TCP congestion control algorithm developed at Caltech's Netlab.
It is necessary to have alpha somewhat larger the threshold so that FAST does not re-enter MI during the initial turn on transient or subsequent transients.
This experiment investigates the performance of FAST in which packets are dropped according to a Bernoulli process, with probabilty 0.0001.
www.cubinlab.ee.mu.oz.au /ns2fasttcp   (703 words)

 Fast TCP, production links, multiple streams
Fast TCP single stream versus a Reno TCP single stream
This is the main page for the tests we are conducting using new TCP stacks on production links.
At this location, it is available a comparison between a Fast TCP single stream and a Reno TCP single stream, from SLAC to several destination.
www-iepm.slac.stanford.edu /monitoring/bulk/tcpstacks/fast-multi.html   (387 words)

 Geek.com Geek News - Fast TCP: the Internet turbocharged
Fast TCP is different, however; the hardware and software required on the sending machine act as a constant monitor for the data being sent.
Fast TCP uses both packet loss and queueing delay as signals of congestion, as opposed to TCP which uses one or the other but not both.
The backbones through which the internet runs between countries and indeed the contenents of the world are not tcp but a wrapped type service, ie as you would have tcp wrappers encasing another protocol such as ssh, they have tcp encased in another protocol that would not be effected by the advantages of Fast TCP.
www.geek.com /news/geeknews/2003Jun/gee20030609020318.htm   (3958 words)

 Caltech Press Release, 3/18/2003, Steven Low, Harvey Newman
The FAST TCP sustained an average throughput of 925 Mbps and an efficiency of 95 percent, a 3.5-times improvement, under the same experimental condition.
With 10 concurrent TCP/IP flows, FAST achieved an unprecedented speed of 8,609 Mbps, at 88 percent efficiency, that is 153,000 times that of today's modem and close to 6,000 times that of the common standard for ADSL (Asymmetric Digital Subscriber Line) connections.
The world record for the current TCP is 10 peta (1 followed by 16 zeros) bmps, using a nonstandard packet size.
pr.caltech.edu /media/Press_Releases/PR12356.html   (1457 words)

 BBC NEWS | Technology | Promise of ultra-fast downloads
Fast TCP was tested in November 2002 when data was swapped between locations in California and Cern near Geneva in Switzerland.
By contrast the Fast TCP system managed an average speed of 925 megabits per second over the same route.
The CalTech team say the Fast TCP technology can be bolted on to the existing net infrastructure, which might mean that it comes into use quickly.
news.bbc.co.uk /1/hi/technology/2965184.stm   (355 words)

 Roxen Community: RFC 2581 TCP Congestion Control (Standards Track)
After the fast retransmit algorithm sends what appears to be the missing segment, the "fast recovery" algorithm governs the transmission of new data until a non-duplicate ACK arrives.
When TCP has not received a segment for more than one retransmission timeout, cwnd is reduced to the value of the restart window (RW) before transmission begins.
An attacker can therefore impair the performance of a TCP connection by either causing data packets or their acknowledgments to be lost, or by forging excessive duplicate acknowledgments.
community.roxen.com /developers/idocs/rfc/rfc2581.html   (3656 words)

 What is FAST TCP? - A Word Definition From the Webopedia Computer Dictionary
FAST TCP is an alternative congestion control algorithm in TCP, that is designed to sustain high throughput and utilization for high-speed data transfers over large distance (e.g., tens of gigabyte files across the Atlantic).
The Fast TCP system being developed by Steven Low and colleagues at the California Institute of Technology.
Current implementation is in TCP on the Linux platform, although the principles and design can be implemented in other contexts than TCP.
webopedia.com /TERM/F/FAST_TCP.html   (157 words)

 Slashdot | Fast TCP To Increase Speed Of File Transfers?
TCP works on the premise that packets are mainly dropped when congestion is high enough for routers to drop packets because of maxed buffers.
The difference between UDP and TCP is that TCP is a connection-based, sequence-enforcing protocol, where UDP is basically raw connectionless datagrams that arrive in any order and you have to handle packet loss and reordering in your application.
TCP is extremely bursty - it pumps all the packets it can as fast as it can over the network as soon as the window opens.
slashdot.org /articles/03/06/05/0038250.shtml?tid=126&tid=164&tid=185&tid=95   (7010 words)

 TCP Rate-Halving [PSC]   (Site not responding. Last check: 2007-10-08)
Fast retransmit relies on three duplicate acknowledgements to trigger the retransmission of a single lost segment.
Once the Fast Retransmit has occurred, TCP then waits for enough additional duplicate ACKs to arrive, indicating that half of the data in flight has left the network.
Hoe [Hoe95] suggested that during Fast Recovery the TCP data sender space out retransmissions and new data on alternate acknowledgements across the entire recovery RTT.
www.psc.edu /networking/rate_halving.html   (518 words)

 HighSpeed TCP
Les Cottrell's experiments of TCP Stack measurements, from SLAC, comparing HS TCP, FAST TCP, Scalable TCP, and stock TCP.
HighSpeed TCP implementation from Gareth Fairey at Manchester University and from Yee-Ting Li from UCL, for Linux 2.4.19 and 2.4.20, with experimental results.
One of the issues with HighSpeed TCP is that of long convergence times between new and old HighSpeed TCP flows.
www.icir.org /floyd/hstcp.html   (614 words)

 F. Cela   (Site not responding. Last check: 2007-10-08)
This section introduces the last of the algorithms that led to the Tahoe release of TCP, the Fast-Retransmit algorithm.
Despite this first inconvenience, Fast-Retransmit performs very well during the rest of the transmission; we have reduced the waiting time after drops and so the time the pipe gets completely empty; this can be seen comparing the plots of the queue size evolution.
The effect is a noticeable increase in the throughput: at the end of the experiment, the source implementing the Fast Retransmit algorithm has transmitted succesfully about 20 segments more than the one not implementing it, about a 13 per cent improvement.
www.cs.utk.edu /~dunigan/tcptour/javis/tcp_fastrtx.html   (533 words)

 Model Library: TCP   (Site not responding. Last check: 2007-10-08)
Transmission Control Protocol (TCP) is a widely used connection-oriented transport layer protocol that provides reliable packet delivery over an unreliable network.
The TCP standard model is designed to be used with the IP standard model; however, it could also be modified for use with other network layer protocols
OPNET's finite state machine (FSM) representation of the TCP protocol is taken directly from the TCP RFC protocol description, and provides the model developer with tremendous flexibility in developing protocol models.
www.opnet.com /products/library/tcp.html   (382 words)

 [No title]
Standards Track [Page 2] RFC 2581 TCP Congestion Control April 1999 LOSS WINDOW (LW): The loss window is the size of the congestion window after a TCP sender detects loss using its retransmission timer.
When TCP has not received a segment for more than one retransmission timeout, cwnd is reduced to the value of the restart window (RW) before Allman, et.
Security Considerations This document requires a TCP to diminish its sending rate in the presence of retransmission timeouts and the arrival of duplicate acknowledgments.
www.rfc-editor.org /rfc/rfc2581.txt   (3830 words)

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