[arin-ppml] IPv6 Heretic thoughts

Cliff Bedore cliffb at cjbsys.bdb.com
Sat Sep 6 13:35:09 EDT 2008

Iljitsch van Beijnum wrote:
> On 4 sep 2008, at 19:40, Cliff Bedore wrote:
>> Having been reading this group for approaching a year or so now, I think
>> I've seen the problem with adopting IPv6.  Nobody really wants it.
> I don't think that's true.
> Most people don't know enough to either want it or not want it. Of the 
> people who know, I'm pretty sure a decent number want it, but the 
> trouble is that if you're the only one running IPv6, it doesn't do 
> much for you. Other people have to run it, too.
> As someone how used to configure routers for a living, I want IPv6, 
> because it makes my former job easier. (But few people configure 
> routers, let alone for a living.)

OK Let's say there's great apathy for IPv6.  Based on adoption rates, 
those in a position to "make it happen" don't care enough to make it 
happen. (Don't care can be taken to mean "won't spend the money" in many 
>> The problem:  There is no compatibility bit in IPv6 that says I'm just
>> like IPv4 but I have 96 more address bits.
> Although it doesn't seem like it, the current situation is as good as 
> it gets. For the details:
> http://www.bgpexpert.com/article.php?article=106
>> The backbone for the Internet will have to
>> be IPv6, DNS will have to be IPv6
> Not a problem. I already get 10 - 20 % IPv6 hits on my DNS server and 
> 25 - 50 % of the big backbone networks have some kind of IPv6 running 
> today.

I'm saying no more IPv4 backbone anywhere.
>> and IPv4 will be treated as IPv6 on
>> the Internet and translated through the "converter box (CB)".  This
>> means that the CB will have to do both translation and DNS lookups for
>> the v4 hosts.
> I'm not sure what you have in mind. The problem is that at some point 
> within the next years, there won't be enough IPv4 addresses to 
> continue current practices. So ISPs will have to figure out a way to 
> connect new customers without being able to give these customers their 
> own address. NAT can solve the immediate problem, but you can't slice 
> and dice public IPv4 addresses forever by adding more NATs.

If at this point, we had the conversion boxes (CBs), there would be no 
further need for IPv4 addresses.  All new addresses would be IPv6.  I 
would have IPv6 addresses issued to me that the outside world would 
point to.  The conversion box would do a one-to-one conversion of my 
outside IPv6 addresses to my IPv4 inside addresses   To the outside 
world, I would be running IPv6.  The big ISPs would have gazillions of 
IPv6 addresses (remember those 128 bits) that could reach my IPv4 web 
page through the CB. They would also have lots of IPv6 address space to 
provide the same one-to-one mapping of IPv6 to IPv4 addresses for their 
existing customers if they needed it..  In this scenario, I would expect 
that organizations like Google, Yahoo, eBay etc would have IPV6 
addresses so all those Comcast, Cox, Charter, ATT and other ISP's 
customers can get to them directly and to me through my CB.
> So at some point end-users will gradually have to start running IPv6. 
> At that point, translation becomes useful because these people can 
> then talk to people who are still IPv4-only. But translation in and of 
> itself doesn't solve anything, and it also incorporates NAT so most of 
> the downsides of IPv4 NAT are still there.

NAT as a method of saving addresses would go away.
>> Since there are 64 bits per subnet in IPv6, there will
>> never be a subnet that can't split off IPv4 addresses through the CB for
>> translation.
> Not sure what you mean and no idea what CB is. (Citizen's band?)

As defined in the original email and above, it is the conversion box (or 
translator) that does the one-to one mapping of IPv6 to IPv4.

>> That's a short summary of a big problem but I think it's obvious that
>> there has been little real adoption of IPv6.
> We don't need IPv6 today. So the fact that we don't see IPv6 today 
> doesn't mean all that much. There's still time.
>> We really need a program
>> that accomplishes what the US HDTV program did.  Tell people that "on
>> MM/DD/YY, the Internet backbone will be IPv6 only.  If you want to run
>> IPv4, you will need one(or more) of the converter boxes for your IPv4
>> addresses.  If you don't do this, you will lose Internet connectivity"
> Ah, but our technology is much more advanced than that. Unlike digital 
> TV (which may or may not be HD) versus analog TV, we can run both IP 
> versions side by side, and even when IPv4 runs out of steam because of 
> lack of addresses, the people who already have an address can keep 
> using it.

As they can in mine but my proposal doesn't require dual stacking
>> 1.  All IPv4 space effectively becomes PI space since you can tuck your
>> IPv4 into any IPv6 subnet
> Unfortunately, this only works in the outgoing direction. In other 
> words: you can put hundreds or thousands of clients behind a single 
> public IPv4 address and translate from their public IPv6 address or 
> private IPv4 address to that public address when they initiate an 
> outgoing session, but receiving incoming sessions is much harder: then 
> the translator needs to know how to map the sessions and the rest of 
> the world needs to know which port number to use (no "80 for web, 25 
> for mail" shortcuts).

As per above, we're not address hiding, we're one-to-one translating.  
Every 64 bit subnet can hold 4 billion different copies of the current 
IPv4 space.(I hope I did that math right.)  All we need to do is say 
something like "If the first bit of the subnet is 1, this is really an 
IPv4 address so ignore the next 31 bits and feed the packet to the CB."  
Or just have 2 subnets, one for native IPv6 and one for translated 
IPv4.  As everybody keeps pointing out, IPv6 has lots and lots of 
address space.  Sure it might be a waste to use 64 bits for an IPv4 /24 
but we've effectively done that anyhow with the 64 bit subnet business.

I'm sure that there are companies who are running something on Windows 
98, SCO Xenix or something similar who may not ever want to update to 
IPv6.  The CB lets them talk to the world via IPv6 for as long as they 
need to run that application.

I guess you could do all kinds of things in the CB to tell it which of 
the upper 32 bits of IPv6 subnet space define IPv4 translation requirements.

I had been thinking of the CB as a standalone box but it could certainly 
be part of a router if that's easier.

Another meaning of CB by the way is Cliff Bedore or the last half of my 
ham radio call of W3CB.  So needless to say "Citizens Band" is fighting 
words to us hams. :-)

Cliff Bedore

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