[Codel] [Bloat] The challenge

[Jonathan Morton]

On 10 May, 2012, at 9:35 am, David Woodhouse wrote:

>>> So overall we have an AQM that provides a low-latency signal of appropriate magnitude to TCPs when the link is genuinely congested, and gets out of the way when it isn't.  Combined with a fair queueing discipline (eg. SFQ or QFQ), I think this will turn out to be an excellent default setting for all sorts of equipment.  What would it take to get this into a DSL modem (at either end of the link)?
>> 
>> David Woodhouse tossed a copy of the paper on his machine before
>> getting on a plane. He's been working on a ADSL device for quite some
>> time. I don't know if he and his box are together, or separated.
> 
> Separated by about five thousand miles right now; I'll be home on
> Monday; awake by Tuesday. OpenWrt supports a bunch of ADSL modems,
> including the shiny dual-port Traverse Geos that I'm using at home. It's
> running OpenWrt trunk, and it's simple enough for me to update the
> kernel.

I want to buy a modem that I can put Linux on, and that supports ADSL2+ Annex M.  Where can I get one?

Vaguely acceptable solutions include CardBus or PCI/PCIe slot modems to put in a PowerBook or a PC.  I have enough spare hardware to make that work, and the lines here are underground and so not susceptible to lightning.

> As for the *ISP* end of the link, we could talk to the ISP about that.
> Their LNS isn't running Linux though; it's their own code.

I suppose the downstream side of ADSL is less vexing for now.  Eventually AQM and FQ needs to be in the DSLAM and cell tower by default, though.

I might have mentioned previously what my local cell tower is like - 30+ seconds (at 500Kbps) of tail-drop FIFO.  Yuck.

 - Jonathan Morton