Comcast's IPv6 CPE selection

[Ted Mittelstaedt]

I will chime in on this as I've had a lot of experience with
this firmware.  For starters there is no "v26" there is only
V24 and "V24 pre-SP2"

First thing to realize with dd-wrt is that the biggest reason
(IMHO) that people use it is that it's rock-solid stable compared
to the vendor firmware.  So new releases take a long time.

Since there's many routers out there with crummy firmware there is
much clamoring for dd-wrt to be ported to ever new platforms, and
a lot of the maintainer's time is spent doing this.

The second thing to realize is that VERY FEW consumer-grade routers
that support 802.11g came with MORE than 4MB of flash.  Originally
many DID come with 4MB - but then later they went to 2MB (such as
the later Linksys WRT54G units) of flash.

The problem here is that the newer DD-WRT firmware using the newer
Linux kernel consumes more space.  Thus, the DD-WRT developers have
spent a huge amount of time figuring out how to delete things from
the newer Linux loads to get them to run on the 2MB flash units.
(Just about all Belkin units for example use 2MB flash)  IPv6
is one of those things.

This means essentially that NO Broadcom-based 54G router with 2MB
and NO Atheros based 54G router with 4MB flash will run a dd-wrt load
that will do IPv6.

The current dd-wrt load is a so-called "beta" of v24 (they call it
pre-SP2 but the new releases have been called that for almost the last 2 
years) it's SVN# 13064, this came out about 4 months ago.  The 
"official" dd-wrt release does NOT contain good IPv6 support.

Because of this, a user crushedhat decided about 2 years ago to fork
off SVN# 10070 and made a huge boatload of changes to it to
support IPv6 properly.  This is detailed here:

http://www.dd-wrt.com/phpBB2/viewtopic.php?p=196058#196058

crushedhat is NOT one of the dd-wrt developers.  He DID post
a set of instructions on how he setup the build environment.

The rapid intro of draft-N routers into the market has changed
dd-wrt development as the developers now appear to mainly be
concerned with expanding the footprint of dd-wrt onto more
hardware.  This is good and bad.  The good part is that many
of the newer draft-N routers (such as the Linksys 160N) shipped
with 4MB of flash or 8MB (Linksys 300N, Netgear WNR3500L, etc.)
but it is bad because the developers never really integrated
CrushedHat's IPv6 changes and probably won't until V24 SP2 is
a reality - and that seems to be in the distant future as they
really aren't working on getting SP2 out the door.

The reality of IPv6 on dd-wrt is you either run the developer
released standard loads (which require 4MB flash minimum)
and have a lot of things missing from IPv6 (traceroute6, etc.)
but are the current SVN#, or you run the 2-year-old Crushedhat
SVN fork which has a complete IPv6 implementation but is not
the current SVN, or you use the Crushedhat instructions and
setup a development environment and pull down the current
SVN source, apply the crushedhat mods, then build that one.

The 2 year old crushedhat release is stable and reliable and
so a lot of people run it.  But it's clear that we are a ways
off from "official" support of IPv6 from the dd-wrt developers
for 4MB flash units.  However, in the long run this may not matter
IF the wireless market jumps en-mass onto the 802.11 N standard.
That is (IMHO) what the dd-wrt developers are betting on, and it's
why they are focusing most of their effort on porting DD-WRT as
quickly as possible to the widest number of N routers that are
on the market, instead of doing what's needed to get a v24 SP2
release out the door.

And all of this also applies only to the command-line interface
to dd-wrt.  The GUI interface would have to be modified to support
all of the IPv6 utilities (like traceroute6) before you could
point to DD-WRT and call it "grandparent ready" and that is not easy
as it's written in an obfuscated manner (to prevent copying, the
GUI is NOT under the GPL like the rest of DD-WRT is)  However, this
isn't any different than OpenWRT, which while it has a good
command-line implementation of IPv6, none of the GUIs that
are out there for OpenWRT support it. (although, those ARE
easily modified)


Ted


On 4/24/2010 7:12 PM, Frank Bulk wrote:
> Ack on that -- hopefully it can be grandparent ready in a few months.
>
> Frank
>
> -----Original Message-----
> From: Doug Barton [mailto:dougb at dougbarton.us]
> Sent: Saturday, April 24, 2010 9:10 PM
> To: frnkblk at iname.com
> Cc: ipv6-ops at lists.cluenet.de
> Subject: Re: Comcast's IPv6 CPE selection
>
> On 04/24/10 18:50, Frank Bulk wrote:
>> And note the "[5]" behind IPv6 feature that says "Apparently, IPv6-related
>> features DO NOT work by default in DD-WRT v24. See IPv6 on v24.", and
>> clicking throught "IPv6 on v24" I see all kinds of "insmod" commands.
>
> The v24 firmwares are all getting pretty long in the tooth, and v26 is
> the recommended version on all routers that support it (which is most of
> the ones that have been manufactured in the last 5 years or so).
>
> And if you read the forum post I included the link to you can see that
> there IS a bit of manual configuration that has to be done, but unlike
> in the past where you had to create numerous boot scripts, install
> packages by hand, ssh into the router, etc. etc.[1] modern versions of
> dd-wrt (except for the very smallest firmwares) already include
> everything you need, and allow you to configure the two things you need
> to get IPv6 working (radvd and the startup commands for the tunnel) from
> the gui.
>
> I'm not saying I'd turn my grandfather loose on this, rather that a
> reasonably capable tech-oriented person could go from stock linksys
> firmware to having their router as a tunnel endpoint and RA on their
> local network in a few hours ... maybe a little more if their
> forum/wiki/google search fu is not up to par.
>
>
> hth,
>
> Doug
>
> [1] Compare http://www.tunnelbroker.net/forums/index.php?topic=106.0
>