IPv6 woes - RFC

Sun Sep 19 20:53:44 UTC 2021

> On Sep 10, 2021, at 00:21 , Bjørn Mork <bjorn at mork.no> wrote:
> 
> Owen DeLong via NANOG <nanog at nanog.org> writes:
> 
>> The addresses aren’t the major cost of providing IPv4 services.
>> 
>> CGN boxes, support calls, increasing size of routing table = buying new routers, etc.
> 
> You're counting dual-stack costs as if IPv4 was the optional protocol.
> That's a fantasy world.  Time to get out of la-la land now.

No, I’m counting them as if they are the increasing cost of continuing to support IPv4.

> Your edge routers can do CGN for all connected users just fine. Yes,
> there is still a cost both in resources and management, but you'll have
> to weigh that against the cost of doing dual-stack on the same box.  I'm
> not convinced dual-stack wins.

It does. At least in my environments.

> Don't know what you're thinking of wrt support calls, but dual-stack has
> some failure modes which are difficult to understand for both end users
> and support.  NAT is pretty well understood in comparison.

Single layer NAT, sure. But double-layer NAT has some oddities that you
might not have encountered yet…

1.	Products which are built on really strange assumptions about everyone
	having the same NAT environment.

	For example, Philips Hue makes an assumption that if you are in the
	same household, your Hue Gateway and your phones and laptops will
	all have the same public IP address.

	This has two unexpected ramifications:

	1.	You cannot actually complete their registration process for their
		cloud services if you don’t NAT everything to the same address
		or proxy it all through a common proxy address.

	2.	If you are behind CGN, you and your neighbors are going to be
		considered a single household (at least everyone behind the
		same CGN address). Of course, this assumes that you get a
		consistent single public CGN address for everything in your
		house. If you don’t, then you get a combination of this problem
		with problem 1 above and life gets very interesting.

2.	NAT Traversal technologies that don’t cope well with an added layer.

3.	Added and inconsistent latency through CGN boxes degrading
	several online experiences, including voice, interactive video,
	and most of all several types of gaming.

There are many more and each of them generates additional support calls
to the ISP about “The internet is broken”.

> Your routing tables won't grow with IPv4 or CGN.  They grow when you add
> IPv6.

Um, please review the IPv4 routing table report over the past few years
and tell me that again.

For your convenience: https://www.cidr-report.org/cgi-bin/plota?file=%2fvar%2fdata%2fbgp%2fas2.0%2fbgp%2dactive%2etxt&descr=Active%20BGP%20entries%20%28FIB%29&ylabel=Active%20BGP%20entries%20%28FIB%29&with=step

> 
>> Increased cost of developers having to work around NAT and NAT
>> becoming ever more complex with multiple layers, etc.
> 
> And this can be avoided by reconfiguring the local network somehow?  Or
> are we talking about an Internet without IPv4?  This is even more
> fantastic than the idea that IPv4 is optional in the local network.

We are talking about internet where IPv4 prevalence continues to drop. Whether
it can be avoided or not, however, it is a factor in the ever increasing cost of IPv4.

> 
>> All of these are the things driving the ever increasing cost of IPv4
>> services, not just the cost of the addresses.
> 
> Yes, the cost of addresses is not prohibitive, and there is no
> indication it will be.

Agreed… But the other costs are also continuing to increase. None of these
costs exist in IPv6 save a one-time deployment cost.

> The consolidation of hosting services have reduced the need for globally
> routable addresses.  You don't host your own mail server and web server
> anymore, even if you're a large organisation.

Lots do, actually.

>  Most ISPs haven't yet
> taken advantage of this.  They are still giving globally routable IPv4
> addresses to customers which have no need for that.  These addresses can
> be re-allocated for CGN if there is a need. This is obviously still not
> free, but it does limit the price of fresh IPv4 addresses.

Lots of things you don’t expect break when you stop giving at least one IPv4 GUA
to your customers.

> The other costs you list will not affect an IPv4 only shop at all.

This simply isn’t true.

Owen