What it will take to shift the Net
page 4: The promise of V6

Cerf: V6 has been around for quite a while. The IETF [Internet Engineering Task
Force] standardized it some time ago, but it hasn't rolled out in any
production sense, because the people who consume Internet resources -- the
ISPs and their customers -- have not been beating up on the equipment
vendors, demanding V6. 
So, Cisco (CSCO) was very reluctant to spend a lot of time and energy trying
to get the production of V6 going until they heard an ISP saying, "I need
it, I will pay for it, I won't buy your stuff anymore if it doesn't have
it." 
So I finally went over to Cisco, not too long ago, at the invitation of
their CTO, and we just sat down and we all talked about what the situation
was, where VG6 was, what the pressure points were, and why this was an issue
for me. I came away feeling as if I had officially raised the attention.
They said, "Nobody's asking for this," and I said, "I am. I'm an ISP and I'm
asking." 
UpsideToday: What must happen for V6 to be deployed? 
Cerf: It's deployed in experimental form or sort of a test form in a number
of places. We run it in something called the VBNS, which is a very high
performance backbone network service. We built that for the National Science
Foundation in October 1994. That network caters to mostly the R&D and
university communities. 
So we run V6 in that network using Cisco software. A number of other vendors
and ISPs are participating in something called the Six-Bone, which is sort
of a spin-off of the M-Bone. The M-Bone is the multicast backbone and the
Six-Bone is the IPV6 backbone. So a bunch of us have been running V6 for a
while. 
But it's one thing to run V6. It's something else to figure out a transition
strategy that actually lets people run in mixed modes, lets V4 and V6
interwork, and lets you spread more and more V6 as time goes on. 
I've asked my engineers to start working on transition strategies and
interoperability tests to see how well we can actually handle the V4 to V6
exchanges. Much to my surprise, in June of last year, the Internet
Architecture Board invited a group to look at IP Version 6 and to see what
the scenarios might be in the future. 
UT: Is one service provider going to have to step forward and say, "We're
going to do this. We're going to go to V6." 
Cerf: I think that there's going to have to be one of those. Everybody's
standing around waiting for somebody to jump in the pool, and I think that
the pressure will build. 
The thing that's going to push us over the hump, I think, will be cable
set-top boxes and cell phones that are Internet-enabled, you know. When
Nokia starts cranking out 80 million cell phones, and then somebody else
starts cranking out 80 million set-top boxes, and they all want to be
IP-enabled, where are they going to get the address space? 
Even if they don't run out, the guys who hand out IPV4 address space are
really parsimonious about it, because the IETF community has given them a
set of guidelines that allows them to be parsimonious, so we don't run out
of address space too quickly. 
So what's the natural reaction? Well, ICANN [Internet Corp. for Assigned
Names and Numbers], the organization that oversees this whole domain name
and IP address allocation process, has officially turned on IPV6
allocations, so now you can go and get a V6 address space allocation, which
we've done, for example, for VBNS. So the process has begun. 
There's a group called the IPV6 Forum that is trying to sound the alarm, so
to speak, to say it's time to get busy preparing for IPV6. So at some point
the vendors will hear that, and, I hope, will start releasing
production-quality V6 code. 
And I hope that Microsoft will go beyond its current experimental
implementation of V6 in an NT framework and go all the way to Windows, I
don't know what, 2001 or 2002 production implementation of V6. And of course
many other people will have to do the same thing. I believe that it's
inescapable that we have to do something. 
UT: Will people wait until it's more difficult than it need be? 
Cerf: It's hard to say. I think that if you wait, you just increase the long
period of time over which you have to do translations back and forth. 
UTe: If all the ISPs are competing for address space, won't ISPs that want
to offer always-on DSL or cable modem have a business incentive to go to V6?

Cerf: That's a good point, and I hadn't thought about making that point to
the ISPs in fact, but that's a good one. You know, generically it's clear
that you use up more address space with all these on. But it didn't occur to
me until you just mentioned it that maybe that would be a good way of
persuading other ISPs to go to V6. 
UT: So, hypothetically, if one of them says, "We've made a commitment to V6,
so we're in a better position to support broadband customers...." 
Cerf: Yeah. It's fair to point out, though, that if you've got a V6 address
and you want to be able to talk to anyone on the Internet, somewhere the V6
address has to convert into V4. So the ISP may be motivated, as you say, but
the customer may have to buy or the ISP may have to supply an NAT [network
address translation] box to be compatible with everybody else. 
In time there'll be enough V6 out there that at some point it will make
sense for a backbone network to flip from running V4 to running V6, and when
they do that, the same NAT boxes will be needed to help the V4 guy
communicate with the V6 world. None of this is going to be easy, and getting
stuff going back and forth between the V4 and V6 networks is going to be an
interesting challenge.