nanog mailing list archives

Re: IPv6 mistakes, was: Re: Looking for an IPv6 naysayer...


From: Scott Helms <khelms () ispalliance net>
Date: Fri, 11 Feb 2011 15:29:35 -0500


Comcast, nor the other large MSOs, are not as monolithic as they may appear from the outside.  In most cases the large MSOs are 
divided into regions that are more or less autonomous and that doesn't count the outlier properties that haven't been 
brought into the fold of the region they are in for various, usually cost related, reasons so don't expect a large block of any 
of those guys to suddenly be at 60% of their users can get IPv6 addresses.

I think you'll be in for a surprise here.
We'll see, I have reasons to be (deeply) skeptical, but I hope you're right. Care to speculate on a time frame for when we might get a pleasant surprise?

While Facebook working over IPv6 will be a big deal you won't get all of their traffic since a significant fraction of 
that traffic is from mobile devices which are going to take much longer than PCs to get to using IPv6 in large numbers.  
Also, Netflix is even more problematic since the bulk of their traffic, and the fastest growing segment as well, is coming 
from Xboxes, Tivos, other gaming consoles, and  TVs with enough embedded brains to talk directly.  Those devices will also 
seriously lag behind PCs in IPv6 support.

I think you'll be in for a surprise here, too. The 4G transition is already underway. For the vendors where 4G means 
LTE, IPv6 is the native protocol and IPv4 requires a certain amount of hackery to operate.
LTE won't be "real" for the vast majority of subs until the they have an LTE handset, which won't happen until they replace their existing 3G phone. That won't happen unless Verizon and AT&T decide to suddenly give people upgrade credits before their contract would allow. What's worse the whole LTE isn't really 4G and will be replaced by LTE+ makes this worse. If you're a phone maker you're likely trying to decide if you've gone to far to delay your product launch or if you can wait for LTE+ chipsets before releasing your new phone.
In the WiMax case (Gee, thanks, SPRINT), things are a bit murkier, but, I think you will see WiMax go IPv6 pretty 
quickly as well.

Yes, it will take a little longer to retire the 3G system(s) than many other parts of the internet, but, I think you 
will see most of it going away in the 5-7 year range.
3G will be around in substantial amounts for at least 10 years outside of the top 20 metro markets.
You misunderstand how getaddrinfo() works under the hood. The code itself first does an AAAA lookup and then does an A 
lookup. DNS does not return both record sets at once. If there is an AAAA record, it will return first.

Some OS have modified things to resort the getaddrinfo() returns based on the perceived type of IPv6 and IPv4 
connectivity available as an attempt to reduce certain forms of brokenness. However, even in those cases, you should 
get the AAAA first if you have real IPv6 connectivity.
I haven't looked at the code so that it is entirely possible, but I am more concerned with what the content providers do. Does MS implement the POSIX function? I don't know, but if not whatever Win(XP-7) does is much more important to traffic than what all of the BSD and Linux variants do.

Right now you can have a completely working dual stack set up and if your ISP's name server isn't on Google's (and a host of others) white list you'll never get the AAAA record no matter what order your client resolver code asks for the addresses in.

http://tools.ietf.org/html/draft-ietf-v6ops-v6-aaaa-whitelisting-implications-02

http://arstechnica.com/web/news/2010/03/yahoo-wants-two-faced-dns-to-aid-ipv6-deployment.ars


The point here is that there are multiple hoops that have to navigated and if any one of them is missed the client will work over v4 and that will keep the ramp up of v6 traffic modest for a long time to come. BTW, I don't want to be right here but I know intimately how ISPs, CPE vendors, and customers behave.




--
Scott Helms
Vice President of Technology
ISP Alliance, Inc. DBA ZCorum
(678) 507-5000
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http://twitter.com/kscotthelms
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