6 weeks of backlogged news

Posted on Apr 17, 2011 by Dave Täht.

I’d intended to write up summaries of bufferbloat related activity once a month, but am running a bit behind. Both JG and I have been travelling heavily.

There’s been a lot going on under the covers!

Probably the biggest news is that we are working with Georgia Tech on their bismark project.[1] They are out to diagnoise the Internet and we are out to fix it. The two goals seemed compatible. In particular: we are trying to de-“heisenbug” the test routers so they can accurately test the upstream services.

We’ve also taken the wraps off the “uberwrt” project[2], which is an attempt to get the debloating work TESTED in realistic situations at the edge and also into openwrt. (Some work from this also flows into bismark)

I was going to write formal joint press releases on these but have been too busy traveling, talking and hacking. (if anyone wants to step up to handle PR?)

Although traffic on the bloat mailing list has been slow of late, the bismark-devel list has been hopping. Feel free to join bismark/uberwrt projects and/or the mailing list[3], especially if you are interested in embedded hardware.

Moving on to other topics…

Based on the early difficulties in getting debloat-testing to be a useful base for the eBDP and A* algorithms, we started looking around for ONE driver to work with and have settled on ath9k hardware (for now) as a base for routers and wireless cards. [10] We need to do a little testing of the laptop cards, but things are looking good. the WNDR3700v2 is AWESOME, actually. 16MB of flash. LUXURY.

Other Patches:

Dan Siemon’s pfifo_fast fix for ECN has been backported into 2.6.37.X for openwrt’s git head as of Saturday. It’s also now part of 2.6.39 and 2.6.38 stable.

SFB is in mainline Linux 2.6.39-RCX and woefully undertested in its current incarnation.

Felix Feitkeu has some patches more fully instrumenting the ath9k driver (when mildly more complete, these should get slammed into debloat-testing as well) [4]

Dan Siemon has improved both his TC shaper test scripts and ping-exp [5]

Media: There were a couple articles on bufferbloat that went by this month, I think they were all covered on this list…

There are 236 members of the bloat list now.


We are moving a ton of work to a new build server and also moving the lists machine to that. Regrettably as I write, “huchra” is down due to finger-foo. It should be back up again Monday.

Multiple other servers in other locations are in the queue. I hope to get that sorted out with isc while I am in California.

Upcoming Travel:

JG will be in California April 25-30. I will also be in California April 25-30 (in at least one of the same places as JG), and am available for additional talks/coding/consulting/etc along the western seaboard in early May if anyone wants me and can cover my expenses. (Sort of scheduled: Byte and Atheros U) I’ll also be visiting Seattle at some point in May, too.

Travel last month:

JG spent spent several weeks in Europe, first attending the Wireless BattleMesh conference[6], then the IETF, giving a shorter version of his bufferbloat talk[7].

I spent a week in florida gathering strength for my world tour. Then I spent a week with Georgia Tech helping get their Bismark project off the ground and hammering out workflow issues.

I was tickled pink when I gave an introductory talk on bufferbloat to a class there, only to discover when Q&A rolled around that everyone participating was already up to speed on bufferbloat and queueing disciplines, and peppered me with questions on SFB, RED, eBDP and other algorithms we are playing with. 3 months ago I would have been met with blank looks, now it’s a struggle to keep up!

I then spent a week with esr getting one of the first near-complete builds of the wndr3700 working well, working on gpsd (wanted accurate time on openwrt) and rsnapshot and split dns and a host of semi-bufferbloat.net-and-uberwrt issues… And we also got a revised version of the intro to bufferbloat document up on the wiki [8].

I’m very happy to see thyrsus.com go ipv6 enabled.

The bufferbloat wiki is still in dire need of love, see the Todo list for more details [9] -


And that’s all the news I can remember this late Sunday evening. It’s my hope that SFB will make it into bismark/uberwrt this week so we can test SFB a little more while it is still a RC in 2.6.39. I’d VERY MUCH like to make sure SFB works when it is released to millions of users worldwide. That will be in 4 weeks or so… I’m feeling a little schedule pressure here… See dan siemon’s scripts… [5]

[1] http://www.bufferbloat.net/projects/bismark/wiki Georgia Tech’s project
[2] http://www.bufferbloat.net/projects/uberwrt/wiki [3] https://lists.bufferbloat.net/listinfo/ (bismark, bismark-devel)
[4] http://www.bufferbloat.net/projects/uberwrt/wiki/Experimental_patches [5] http://git.coverfire.com/ PLEASE PLAY WITH TC, SFB, and PING-EXP![]()![]()
The bandwidth you save may be your own.
[6] http://battlemesh.org/ has summaries and videos from the battlemesh
[7] http://mirrors.bufferbloat.net/Talks/PragueIETF/ [8] The original of the bufferbloat introductory piece was extensively discussed on this mailing list. This versions incorporates most of those changes. If you don’t like this version… It’s a wiki document now! Please feel free to fix, extend, and add links! http://www.bufferbloat.net/projects/bloat/wiki/Introduction [9] LOTS of writing left http://www.bufferbloat.net/projects/bloat/wiki/ToDo

[10] After evaluating multiple routers, http://www.bufferbloat.net/projects/uberwrt/wiki/Hardware_evaluation

the http://www.bufferbloat.net/projects/bismark/wiki/Wndr3700v2 seemed like the best choice

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