From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alan Goodman Date: Mon, 22 Sep 2014 23:02:57 +0000 Subject: Re: [Cerowrt-devel] Correctly calculating overheads on unknown connections Message-Id: <5420AAA1.70203@yescomputersolutions.com> List-Id: References: <6DF5DFA0-D88E-470E-ACB6-37703EA964E7@gmx.de> In-Reply-To: <6DF5DFA0-D88E-470E-ACB6-37703EA964E7@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: quoted-printable To: lartc@vger.kernel.org On 22/09/14 20:52, Sebastian Moeller wrote: >> >This test was ran on a BT Infinity VDSL/FTTC connection with the modem = plugged directly into a CentOS 6 machine which is doing PPPoE. The connect= ion is synced at 80mbit down and 20mbit up. BT restrict downstream speed t= o 77.44Mbps IP traffic. > Thank you very much this is the first data set on a VDSL line I have see= n, and clearly me hypothesis that overhead detection on PTM carriers will n= ot work with the current code is nicely demonstrated. I need to ponder this= a bit more and I might not be able to find a nice solution for those links= ... You're welcome. If you need any more data feel free to drop me a line. >>>I can run the test on a slower BT connection over the week end if anyone= is interested in the results? > I would love to see that especially if the other connection is much slow= er, as I see two possible issues with this data set: The other connection is actually ADSL2, we probably know what the=20 results there will be... I think I shall run the test on a really slow=20 ADSL connection later in the year to double check my overheads though.=20 It seems like a very useful tool. Also thanks for providing some example plots of how it should look.=20 That will allow me to better interpret results in future. > 1) Speed: It might be that your line is fast enough to hide the ATM quant= ization below another quantization (like the 4KHz symbol rate of the indivi= dual carriers) or two many concurrent carriers;) Would it be useful if I limited my upload speed with say hfsc to 1mbit=20 and re-ran the test? Given the above comments in Sebastian=92s very useful emails how would it=20 be best to shape these FTTC connections at present? Without overhead=20 set or something else? Alan