[mdlug] OT: the great IPv6 debate

[Adam Tauno Williams]

On Thu, 2010-04-22 at 16:26 -0400, Aaron Kulkis wrote:
> Dan Pritts wrote:
> > On Thu, Apr 22, 2010 at 03:28:35PM -0400, Adam Tauno Williams wrote:
> >> Nah, working multicast and mobile IP support are a big deal.
> > IPv4 SSM works more or less as well as IPv6 multicast does.
> > Mobile IP support, yeah, that's cool.
> >> And I hardly call the radical reduction of CPU resources to perform
> >> routing to be 'gravy' for backbone routers.  Think about it: IPv4
> >> requires a CRC check at each hop,  do that on every packet in a ^&*^&*@
> >> YouTube video stream for every &^&*# YouTube user at every hop and that
> >> adds up to a lot of processing, ASIC or no ASIC.  Just dispensing with
> >> that is a big deal.
> > somehow, all the packets get moved. 

???  Slower than they could have otherwise.

>  It's a lot less effort to do this in
> > the network than it is to change absolutely everything 

So, just use IPv4 forever?  And there will be protocol overlap for at
least a decade.  Rebuilding all those apps to support filenames longer
than 8 characters was hard too.   And moving from green screens to GUIs.
And transitioning local networks from NetBIOS and IPX to IP.  Somehow we
managed.

> Only for the first packet delivered by IPv6 via that node
> (topologically) within your network.
> After this one-time cost is paid, the benefits of lower costs
> accrue both immediately, and forever.
> >>> Probably the biggest problem is that application software often
> >>> does not handle things gracefully when a supposedly dual-connected
> >>> site is v4-reachable but not v6-reachable.
> >>> Try an experiment; put a bad AAAA record in your DNS for a test web
> >>> server, try to connect using a browser on a v6-configured host.
> >>> (put in a good A record, too).
> >> Eh.  Seriously, that is your complaint?  Fix your DNS.  I don't expect a
> >> client application to compensate for incorrect information.
> > My complaint isn't what happens when DNS is broken.  My problem is 
> > what happens when:
> >   My system has a v6 and v4 address

If there was no IPv6 connectivity your client should not have acquired a
routeable IPv6 address.