[Cerowrt-devel] some of the advanced stuff (sort of) in cerowrt

Dave Taht dave.taht at gmail.com
Tue Apr 10 13:58:08 EDT 2012

It occurs to me that jim and I haven't talked about one of the side
goals of cerowrt that much.

We spent a lot of time, early on, trying to find bits of network
research that seemed promising, make them more usable, and more
available to a wider audience to play with, on something that cost 100

Simply getting to where we had a reliable, well understood, base
platform for real world day to day use - AND research - has taken all
year, and along the way we had to solve a lot of niggling problems.

So here's a list of extra stuff that we felt was potentially useful
and interesting.

And until now, although we'd made the packages more or less work, we
didn't always build them - the build takes long enough as it is! - but
the intent was to make them available as options. I plan to make as
many of these available as possible in the next builds, and
installabblevia the opkg utility.

To me, this is the interesting stuff! Getting to use - understand -
and leverage these fascinating new technologies could eat my entire
life, and darn it, I have another build to do...

I'm always up to adding (or hearing about!) more. There's a huge list
of stuff on the onboard web pages we ship by default and think is
stable and are willing to support, but this is the bleeding edge stuff
that we'd hoped people would try out in the longer run.

* HIP. Boeing uses this to control industrial machinery inside of
other peoples' lans. It holds great potential as  means to keep your
refrigerator updated and safe, as well as provide a useful abstraction
for separating a host's location, from it's identity.
I'd hoped to try this for things like snmp monitoring.

regrettably openhip has a tough problem right now with puzzle
generation in the D1 crypto step on mips and while fascinated by
problems like that normally, ENOTIME. I'm going to build it, merely to
find out if I can get someone else to connect to me on the same arch
and have puzzles fail or succeed...

* Kerberos Kerberos is one of the few universal single signon
facilities that actually works. It's amazing how much nicer my life is
when I'm at a facility that has it on. I don't ever have to login to
anything. While I build the package, convincing the universe to go to
kerberos seems difficult, but as an example of what could be done, if
we get fed up with dealing with capcha I wanted it out there.

* VPN technologies. IPsec is supposed to be an intrinsic part of any
ipv6 implemention. It usually is not, as it's rather thoroughly
over-engineered (and underthought-out when it was developed), but
Strongswan has been part of cerowrt since day one. Convincing people
to try it (and get past the hurdles of cert generation, which is a
PITA) has been a problem.

I ran into so many problems trying to get it to work inside of
corporate firewalls that I gave up on it, but that doesn't mean it's a
problem on the edge in the home. Yet. But I do note that it will work
much better over ipv6 in that you have nearly infinite address space
available, and it does, by default, work with ipv6.

I note that people keep trying to make tcp do everything, and it
can't. UDP based applications can be made work much better, with a
crypto assist...

Frustrated with ipsec, I got openvpn to work, over both udp and tcp.
As it turned out, the only thing I could get through the firewall in
france was openvpn over tcp, and working through that was a profound,
painful demonstration of the benefits of e2e connectivity over udp!

Both are built into cerowrt at present.

* TCP fast open. We've been tracking this work closely, but patches
are not going to land for a month or two more, and will need to bake a
bit. You can look up this topic on the web - it looks promising to cut
10% or more of the typical latency of a short tcp connection.

* CCNX: Both jim and I are huge fans of this project, check it out.

Steve walker got previous version of ccnx to build, I updated to the
latest release and broke it. :(

* Openflow: Stanford in particular is doing research into making
multiple switches act as one big switch, with a common configuration
language. It's interesting, especially if you think bridging can

* Mesh routing protocols: While the default in cerowrt is babel, we've
been tracking the progress of quagga-re closely, which includes bgp,
ripng, ospf, ospfv6, isis, and babel. We also make available olsr, and
xorp - which is roughly a superset of quagga, with additional support
for multicast routing that I haven't explored, because xorp is kind of
large. It is however widely used.

Regrettably the xorp package is mildly broken at present (just needs
love from someone) and someone needs to fix it, if they care. At the
moment, quagga gets most of the other interesting protocols available,
so I don't care. That much.

* tcp-ledbat: ledbat is the underlying protocol of current bittorrent,
and it has problems.TCP-ledbat is an implementation for tcp, and is
available by default.

* Test tools: One of the things I'm happiest about now is that the
netperf tool now has the ability to change socket priorities,
tcp congestion control algorithms, and TOS/Diffserv settings on the
fly - for both sides of the test - via remote control.
Interestingly - Diffserv settings don't generally survive an ipv4
connection across the internet, ipv6 settings do.

There are innumerable test tools that we have available (shaperprobe,
ditg, lft traceroute, etc)

* Multicast: Multicast was a hot topic in the 90s and nearly dead now,
except for those few critical applications where it's absolutely
required. (which is a broader category than most people think. Without
multicast dns, dhcp, and radvd, none of our networks would work at
all) Being able to use it again, at a higher level application, seems
like a useful avenue to explore in the context of a home. Available
since the first cerowrt boot camp has been a version of multicast ftp
(uftp), pimd is on by default, mrd6 is there but too buggy to use...

That about covers all the sexy stuff that I can remember.

I've finished adding these all back in the build that I could, for my
next attempt at a release late this week.

happy hacking.

Dave Täht
SKYPE: davetaht
US Tel: 1-239-829-5608

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