ISP Information:
The part of the TCP/IP suite of protocols that is responsible for forming data connections between nodes that are reliable, as opposed to UDP, or IP, which TCP is based on, and which is by default connectionless and potentially unreliable.
ISP Glossary:
Transmission Control Protocol - I did some modem tests on a network to a company that had someproblems when they used V.90 and V.34 modems. I did some changes tothe network, and to see how clean the connection was I run the modemsin buffermode and disabled the error/ flowcontrol. I got a cleanconnection on the V.34 and on 40000 with the V.90 modem, but if I usedhigher speeds on the V.90 I got some bursts (0.01% when I run trafficfor 20 min). I have tried to find out why this happens and I haven'tfound a direct answer but I think it's because of the high samplingrate and/or that the analog and the digital modem are doing somespeed/level negotiation.Regards LarsAaron Leonard wrote in message news:... Your connection looks dandy at the modulation layer, but it seems that you have failed to negotiate error control (LAPM or MNP4.) This will cause reduced performance, and will cause errored data to be delivered to your application unless you are using some error detecting/correcting protocol at a higher layer (like PPP/IP/TCP.) Indeed, if using a modern modulation like V.34 or V.90, it is quite normal for a non error controlled modem link to deliver errored data (even when "idle"). Can you please explain why you would not want to use error control?? Aaron --- ~ Hi ~ I have done some testing with a U.S.Robotics56K modem at a speed of ~ 50666/31200 in buffer mode with no error control, and if I only are in ~ data phase and I'm not sending or receiving any data I can see that ~ I'm getting some noise or bursts that I'm not expecting. I don't think ~ all of this is line noise but I'm not 100% sure. What I think is that ~ this is some signaling between the digital modem and my modem? How ~ does the modem behave when it's in data phase? ~ ~ U.S. Robotics 56K FAX EXT Link Diagnostics... ~ ~ ~ Modulation V.90 ~ Carrier Freq (Hz) None/1920 ~ Symbol Rate 8000/3200 ~ Trellis Code None/64S-4D ~ Nonlinear Encoding None/ON ~ Precoding None/ON ~ Shaping ON/ON ~ Preemphasis (-dB) 0/2 ~ Recv/Xmit Level (-dBm) 20/16 ~ Near Echo Loss (dB) 18 ~ Far Echo Loss (dB) 0 ~ Carrier Offset (Hz) NONE ~ Round Trip Delay (msec) 89 ~ Timing Offset (ppm) 3756 ~ SNR (dB) 49.3 ~ Speed Shifts Up/Down 0/0 ~ Status : aa,5,13N,13.2,-0,0N,0,46.4,19.20 ~ ~ U.S. Robotics 56K FAX EXT Link Diagnostics... ~ ~ Chars sent 0 Chars Received 22813 ~ Chars lost 0 ~ Octets sent 0 Octets Received 0 ~ Blocks sent 0 Blocks Received 0 ~ Blocks resent 0 ~ ~ Retrains Requested 0 Retrains Granted 0 ~ Line Reversals 0 Blers 0 ~ Link Timeouts 0 Link Naks 0 ~ ~ Data Compression NONE ~ Equalisation Long ~ Fallback Enabled ~ Protocol NONE ~ Speed 50666/31200 ~ V.90 Peak Speed 50666 ~ Last Call 00:20:36 ~ ~ Best regards, ~ Lars Homlung
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