From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ed Wildgoose Date: Wed, 23 Jun 2004 08:15:59 +0000 Subject: Re: [LARTC] Modems: Cable or DSL digital blunders that lartc may Message-Id: <40D93C3F.9060707@wildgooses.com> List-Id: References: <20040622043359.75922.qmail@web11905.mail.yahoo.com> In-Reply-To: <20040622043359.75922.qmail@web11905.mail.yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: lartc@vger.kernel.org >Yes, SwFC is lame. Howerver it would be a good band-aid, to have router >and modem syncronisation take place. > =20 > You have got to consider that some devices are asynchronous and some are=20 synchronous >The router(PC) has no idea of the buffer fullness, this is the underlying >problem! The cable modem needs to triger a "pause" when it's buffer >reaches %80 full, regardless of any other rate limiting. Linux kernel can >do this with some cards, under heavy CPU strain(htb). > >CONFIG_NET_HW_FLOWCONTROL: net/Kconfig > =20 > Possibly, but this doesn't help you that much. If your http download is=20 whacking out packets then your SSH session will still effectively get=20 crowded out. You want something to queue for a bit and prioritise this extra traffic. ...you have read the LARTC Howto haven't you? >>You need something which works at IP level or above. TCP (level higher) >> =20 >> >No, the DEVICE is not > layer 3. It's simply a bridge, with a stoplight >on one end. The idea is to not make any cars crash, that has nothing todo >with the ball game a car might want to get too. > =20 > ?? >Yes, ECN will/should be used for routers attached to bridges. > =20 > Not as far as I am aware? (today) >>broadly unsupported. ICMP stuff is frequently dropped by=20 >>routers/firewalls making it problematic (look at how difficult it is=20 >>just to do MTU discovery!) >> >> =20 >> >ECN makes this a non-issue. > =20 > ??? Eh? >>What's your question though? Read the LARTC howto and the ADSL QOS=20 >>howto. They are both excellent docs. Also read up on some basic TCP=20 >>notes. There is nothing really clever that you can do - it's all in the >> >>docs you just have to work around the limitations of the protocols >> >> =20 >> >I would like to know is maby a ?$6000.00? Cisco cable mobem will not only >use HwFC but ECN as well? Thought i'd like to find a $150.00 modem that >will just do HwFC, maby an internal one? > =20 > No it won't. Well, even if it did, I don't think it would help. Unless=20 the rest of the world understands your protocol then you will still have=20 problems with incoming connections. You can get a =A3250 cisco adsl modem which looks rather powerful. Try=20 that if you want to experiment. Please, please read the LARTC-Howto and ADSL-qos howto. I think it has=20 everything that you need. > =20 > >>Ed W >> >> =20 >> > > > > =09 >__________________________________ >Do you Yahoo!? >New and Improved Yahoo! Mail - Send 10MB messages! >http://promotions.yahoo.com/new_mail=20 >_______________________________________________ >LARTC mailing list / LARTC@mailman.ds9a.nl >http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/ > =20 > _______________________________________________ LARTC mailing list / LARTC@mailman.ds9a.nl http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/