Date: Fri, 29 Jan 1999 11:15:23 +0300 From: "Igor Sysoev" <igor@nitek.ru> To: <freebsd-questions@FreeBSD.ORG>, <robert@chalmers.com.au> Subject: Re: Turning off VJ compression. Is it necessary Message-ID: <199901290816.LAA23042@gate.nitek.ru>
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> From: Robert Chalmers <robert@chalmers.com.au> > Subject: Turning off VJ compression. Is it necessary > > I see from the archives that if modem compression is turned off, then VJ > compression operates more efficiently. Among other things.. > quote:............ > 3. Modem compression, as you have noticed, often interferes with VJ > compression used in SLIP and PPP implementations. I don't think so. > 2. Modem compression often interferes with, and lengthens transfer of, > compressed files such as .gz and .jpg. Yes, it's true. But besides compressed files there are HTML, mail, news. They have good compressed rates even with v.42bis. > 1. Modem compression slows down turn-around time -- terrible for > interactive sessions. As far as I know turn-around time slowed by v.42 because it uses blocks to transfer. Modem compression's impact is minor here. > pppctl indicates that VJ Compression is on, on the ppp link, although I know I > turned compression off in the modem (%C0 - Hayes Accura). > > But, is there any improvement in turning off VJ Compression as well, or is it > better left on? You better left VJ. In my ppp connection it reduces TCP/IP headers of 60%-100% packets from 40 bytes to 3-16 bytes. Igor Sysoev To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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