From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-x22f.google.com (mail-ig0-x22f.google.com [IPv6:2607:f8b0:4001:c05::22f]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 7E1E621F19C for ; Sat, 11 Jan 2014 12:23:01 -0800 (PST) Received: by mail-ig0-f175.google.com with SMTP id uy17so1269006igb.2 for ; Sat, 11 Jan 2014 12:23:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=7V2NN/V0a3Grbzw/KrYneDMNZs4Sk+Jp7DIL4qy+V/U=; b=FIA+0B9HX+sE/a2x5tZ5OtMR0vyBYUBdy3XCB1eCK6dnuKxr6VZ59+UGx88ppovnCA rTl60qCVZLh8NFQMLfzjb5XnCjqwCkSrNfMChDpeWBHg1t/JqVbkuODEbeiDNulOtUou +YNUfxNSk9RdvXn+4BAtgsdOyLMDOTeRsZHXt6xhpi1Rq7p+twjPuvC5i0l9/tpv1qxI 78WENeb4E604UncVWKHQM7lUeYf8nPh9Ww83zhA7jZTygkTmywKY1RdYFFI+wwbv0N3l 1hjjeoXiG6x9acuwReEJTSiKinA7cfgWmjYXTepBipQSe2H0Ck56/CwongT77UvELsiw Qkfw== MIME-Version: 1.0 X-Received: by 10.50.100.170 with SMTP id ez10mr10849625igb.15.1389471780725; Sat, 11 Jan 2014 12:23:00 -0800 (PST) Received: by 10.64.248.70 with HTTP; Sat, 11 Jan 2014 12:23:00 -0800 (PST) In-Reply-To: <10B5A5C1-A4D7-429D-A57D-21612B5169E1@gmail.com> References: <4B0976EC-5224-4E81-B5DF-96A85424FB6E@gmail.com> <49DBDBE7-BF76-4823-B723-670935A55833@gmx.de> <10B5A5C1-A4D7-429D-A57D-21612B5169E1@gmail.com> Date: Sat, 11 Jan 2014 21:23:00 +0100 Message-ID: From: Aaron Wood To: Rich Brown Content-Type: multipart/alternative; boundary=e89a8f3b9e5fea6c3a04efb79b77 Cc: cerowrt-devel Subject: Re: [Cerowrt-devel] VDSL X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 11 Jan 2014 20:23:11 -0000 X-List-Received-Date: Sat, 11 Jan 2014 20:23:11 -0000 --e89a8f3b9e5fea6c3a04efb79b77 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Rich, Sebastian, (and others), First, a hello. I've been lurking on the bufferbloat mailing list for a bit, and just joined here as well to better follow what's going on, and see if there's any way I can help. Next, I have an ADSL+ link in Paris (Free.fr), and am willing to run a number of tests using the various LLA options and overhead estimations. But 3 hours on a dead-quiet link could be hard to deal with. I'm happy to run an hour's worth of netperf tests to a nearby server, slowly working through the parameter space, and then comparing the results. My ad-hoc comparisons last week with various modes showed that too high of settings for the overhead (coupled with the already reduced bw limit in the shaper) killed the bulk upload/download performance (which I care about on a meager 18Mbps/1Mbps link). But I found that setting the bw shaper limit to the reported line speed (from the modem), and then adjusting the overhead parameters got me the same bulk performances, with the same latencies (or what appeared to be the same, I need to do more data crunching on the results, and run again in a quieter setting). It would also help if my target server was closer than it is. The only server I know of is in Germany, 55ms away (unloaded). OTOH, I can say that any changes here over the defaults are still gilding the lily (to an end user). But Free.fr's router/modem already uses codel, so it wasn't that bad to begin with (vs. Numericable on a docsis 3 Netgear router/modem). =3D=3D=3D I can also say that I found the current verbiage on that particular page a bit "clear as mud". Even knowing what my network is (to some degree, since the Free.fr modem can tell me), it was difficult to follow, and I quickly found myself at about 3/4 my previous speeds, with no visible improvement in latency (although that could have been a measurement tool issue, as I was doing 60-second runs using the rrul netperf loads). The main question I have is: - Should we both limit the bandwidth well below the reported line rate (or measured IP rate) AND use the link layer adaption settings? (85-90% of bandwidth) or - rely on the LLA settings to do the overhead, and shape to just a tiny bit under the reported line rate? (95-99% of bandwidth) Thanks, - Aaron Wood On Sat, Jan 11, 2014 at 8:06 PM, Rich Brown wrote= : > Hi Sebastian, > > >>> Well, that looks like a decent recommendation for the wiki. The > SQM configuration page still needs to expose all three values, atm, > ethernet, and none so that people can actually change things... > >> > >> So two questions really: > >> > >> 1) (From my previous note) What=92s the difference between the current > =93Ethernet=94 (for VDSL) and =93None=94 link layer adaptations? > > > > Currently, "none" completely disables the link layer adjustments, > "ethernet" enables them, but will only use the overhead (unless you speci= fy > an tcMPU, but that is truly exotic). > > > >> > >> 2) When we distinguish the Ethernet/VDSL case, I would really like to > use a different name from =93Ethernet=94 because it seems confusingly sim= ilar > to having a real Ethernet path/link (e.g., direct connection to internet > backbone without any ADSL, cable modem, etc.) > > > > On the one hand I agree, but the two options are called "ATM" > (well for tc "adsl" is a valid alias for ATM) and "ethernet" if you pass > them to tc (what we do), and I would really hate it to hide this under > fancy names. I see no chance of renaming those options in tc, so we are > sort of stuck with them and adding another layer of indirection seems too > opaque to me. This is why I put some explanation behind the option names = in > the list box=85 > > Now I see how it works. (I didn=92t understand that =93None=94 really mea= nt > NONE.) The following choices in the Link Layer Adaptation would have ease= d > my confusion: > > - ATM (almost every type of ADSL or DSL) > - Ethernet with overhead > - None (default) > > Then the text can say: > > =97 > You must set the Link Layer Adaptation options so that CeroWrt can perfor= m > its best with video and audio chat, gaming, and other protocols that rely > on short packets. The general rule for selecting the Link Layer Adaption = is: > > * If you use any kind of DSL/ADSL connection to the Internet (that is, if > you get your internet service through the telephone line), you should > choose the =93ATM (almost every type of ADSL or DSL)" item. Set the > Per-packet Overhead to 44. > > * If you know you have a VDSL connection, you should choose =93Ethernet w= ith > overhead" and set the Per-packet Overhead to 8. > > * If you use Cable modem, Fiber, or another kind of connection to the > Internet, you should choose =93None (default)=94. All other parameters wi= ll be > ignored. > > If you cannot tell what kind of link you have, first try using "None", > then run the [[Quick Test for Bufferbloat]]. If the results are good, > you=92re done. Next, try the ADSL/ATM choice, then the VDSL choice to se= e > which performs best. Read the **Details** (below) to learn more about > tuning the parameters for your link. > =97 > > Would that be better? Thanks. > > Rich > _______________________________________________ > Cerowrt-devel mailing list > Cerowrt-devel@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/cerowrt-devel > --e89a8f3b9e5fea6c3a04efb79b77 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable
Rich, Sebastian, (and others),

First, a= hello. =A0I've been lurking on the bufferbloat mailing list for a bit,= and just joined here as well to better follow what's going on, and see= if there's any way I can help.

Next, I have an ADSL+ link in Paris (Free.fr), and am w= illing to run a number of tests using the various LLA options and overhead = estimations. =A0But 3 hours on a dead-quiet link could be hard to deal with= . =A0I'm happy to run an hour's worth of netperf tests to a nearby = server, slowly working through the parameter space, and then comparing the = results.

My ad-hoc comparisons last week with various modes show= ed that too high of settings for the overhead (coupled with the already red= uced bw limit in the shaper) killed the bulk upload/download performance (w= hich I care about on a meager 18Mbps/1Mbps link). =A0But I found that setti= ng the bw shaper limit to the reported line speed (from the modem), and the= n adjusting the overhead parameters got me the same bulk performances, with= the same latencies (or what appeared to be the same, I need to do more dat= a crunching on the results, and run again in a quieter setting).

It would also help if my target server was closer than = it is. =A0The only server I know of is in Germany, 55ms away (unloaded).

OTOH, I can say that any changes here over the defau= lts are still gilding the lily (to an end user). =A0But Free.fr's route= r/modem already uses codel, so it wasn't that bad to begin with (vs. Nu= mericable on a docsis 3 Netgear router/modem).

=3D=3D=3D

I can also say that = I found the current verbiage on that particular page a bit "clear as m= ud". =A0Even knowing what my network is (to some degree, since the Fre= e.fr modem can tell me), it was difficult to follow, and I quickly found my= self at about 3/4 my previous speeds, with no visible improvement in latenc= y (although that could have been a measurement tool issue, as I was doing 6= 0-second runs using the rrul netperf loads).

The main question I have is:

-= Should we both limit the bandwidth well below the reported line rate (or m= easured IP rate) AND use the link layer adaption settings? (85-90% of bandw= idth)
=A0or
- rely on the LLA settings to do the overhead, and sha= pe to just a tiny bit under the reported line rate? (95-99% of bandwidth)

Thanks,

- Aaron Wood


On Sat,= Jan 11, 2014 at 8:06 PM, Rich Brown <richb.hanover@gmail.com>= ; wrote:
Hi Sebastian,

>>> =A0 =A0 Well, that looks like a decent recommendation for the = wiki. The SQM configuration page still needs to expose all three values, at= m, ethernet, and =A0none so that people can actually change things...
>>
>> So two questions really:
>>
>> 1) (From my previous note) What=92s the difference between the cur= rent =93Ethernet=94 (for VDSL) and =93None=94 link layer adaptations?
>
> =A0 =A0 =A0 Currently, "none" completely disables the link l= ayer adjustments, "ethernet" enables them, but will only use the = overhead (unless you specify an tcMPU, but that is truly exotic).
>
>>
>> 2) When we distinguish the Ethernet/VDSL case, I would really like= to use a different name from =93Ethernet=94 because it seems confusingly s= imilar to =A0having a real Ethernet path/link (e.g., direct connection to i= nternet backbone without any ADSL, cable modem, etc.)
>
> =A0 =A0 =A0 On the one hand I agree, but the two options are called &q= uot;ATM" (well for tc "adsl" is a valid alias for ATM) and &= quot;ethernet" if you pass them to tc (what we do), and I would really= hate it to hide this under fancy names. I see no chance of renaming those = options in tc, so we are sort of stuck with them and adding another layer o= f indirection seems too opaque to me. This is why I put some explanation be= hind the option names in the list box=85

Now I see how it works. (I didn=92t understand that =93None=94 really= meant NONE.) The following choices in the Link Layer Adaptation would have= eased my confusion:

- ATM (almost every type of ADSL or DSL)
- Ethernet with overhead
- None (default)

Then the text can say:

=97
You must set the Link Layer Adaptation options so that CeroWrt can perform = its best with video and audio chat, gaming, and other protocols that rely o= n short packets. The general rule for selecting the Link Layer Adaption is:=

* If you use any kind of DSL/ADSL connection to the Internet (that is, if y= ou get your internet service through the telephone line), you should choose= the =93ATM (almost every type of ADSL or DSL)" item. Set the Per-pack= et Overhead to 44.

* If you know you have a VDSL connection, you should choose =93Ethernet wit= h overhead" and set the Per-packet Overhead to 8.

* If you use Cable modem, Fiber, or another kind of connection to the Inter= net, you should choose =93None (default)=94. All other parameters will be i= gnored.

If you cannot tell what kind of link you have, first try using "None&q= uot;, then run the [[Quick Test for Bufferbloat]]. If the results are good,= you=92re done. Next, =A0try the ADSL/ATM choice, then the VDSL choice to s= ee which performs best. Read the **Details** (below) to learn more about tu= ning the parameters for your link.
=97

Would that be better? Thanks.

Rich
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