Date: Sun, 24 Feb 2002 11:42:42 -0500 From: "Joe & Fhe Barbish" <barbish@a1poweruser.com> To: "Maren S. Leizaola" <maren@leizaola.com> Cc: "FBSDQ" <questions@FreeBSD.ORG>, "Rod Person" <roddierod@yahoo.com> Subject: RE: SQUEEEZING the most bandwidth out of a 33.6 modem Message-ID: <LPBBIGIAAKKEOEJOLEGOKEKKCIAA.barbish@a1poweruser.com> In-Reply-To: <Pine.WNT.4.43.0202242343560.-408861@hades.leizaola.com>
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-----Original Message----- From: owner-freebsd-questions@FreeBSD.ORG [mailto:owner-freebsd-questions@FreeBSD.ORG]On Behalf Of Maren S. Leizaola Sent: Sunday, February 24, 2002 11:04 AM To: Joe & Fhe Barbish Cc: FBSDQ; Rod Person Subject: RE: SQUEEEZING the most bandwidth out of a 33.6 modem On Sun, 24 Feb 2002, Joe & Fhe Barbish wrote: | The connection speed using a 56k enabled modem is a function of | phone line conditions and speed of PC (cpu mhz & bus mhz). | That being said, many people watch what the connection speed is | for each time they dial into their ISP. Because of line conditions | you do not connect at the same connection rate all the time. | You will get a spread of connection rates like 48000, 49666, 50660, | 52000, most users will just hangup the call and dial again until | they get the rate they want. This can be automated at the modem | hardware level. Lets say you have been watching and 60% of the time | you connect at 49666 or better, but the rest of the time you | hangup and dial again. Well you can use the hays AT commands to tell | the modem hardware not accept any connection speeds less that 49666 Question? Shouldn't V.90 modems be able to negotiate a speed fall forward if the link quality is there? Or did they forget to put that in the standard? If the answer is yes does forcing the modem 52K have much of a point? Also is there much point of pursuing 52K handshake as the modem will fall backward as required on speed and even if you got a 52K will go down to 49.6 or less and I doubt you will be able to query the modem speed. Is there any way of during a coonection disable PPP, kick the modem into command mode and find it what rate the connection is at? Maren. V.90 & V.92 have fall forward and fall backward to handle changing line conditions. I think you have missed the point of using s38. The conditions of each individual phone circuit vary greatly. If the circuit is so poor when you dial in to your ISP that you only get connected at 48000 the likely hood of it getting better during it's use life time is very unlikely to none. By setting s38 to some minimum value the modem hardware will hangup the poor circuit and get a completely new, different circuit path each time it redials until it gets a connect rate higher that the one you specified in s38. The key here is the new, different circuit path which may have better or worse line conditions. But the modem will keep trying until it finds a circuit the meets or surpasses the minimum connection speed you want. Once the connection is made I know of no way to see the connect rate on the fly. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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