Subject: Re: Deployment vs the IPv6 community's ambivalence towards large providers

From: Vernon Schryver <[email-masked]>
Date: Tue, 22 Aug 2000 07:48:11 -0600 (MDT)

> From: Robert Elz <[email-masked]>

>   | Funny, that's EXACTLY what an ATM fan said to me in 1995!
>
> ATM was never rational competition for IP, it competes with FDDI,
> ethernet, frame relay, ...
>
> I understand that some ATM advocates thought it could replace everything
> but that was never rational.   On the other hand, IPv6 and IPv4 are
> essentially the same.   Except IPv6 has enough addresses for everyone.
> As soon as there's an application which requires global addresses for
> lots of devices (and IP phones just might be that application, if they're
> not, something else will be) the continued life of IPv4 with NAT to make
> its apparent address space bigger is doomed.

That's unfair to the ATM advocates or too generous to the IPv6 advocates.
The hope that ATM to the desktop would replace IP was a telephant hope
of a dream of a delusion, but consider the parallels:

Both IPv6 and ATM-to-the-desktop-and-replacing-IP
   - claim more host addresses than humanity will ever need
   - claim much better QoS mechanisms
   - involve tunneling IPv4 until the transition is complete
   - require major changes to applications, hosts TCP code, and the boxes
       that connect hosts.
   - claim to be desert toppings AND floor waxes
   - suffer standards committee bloat and silliness, such as the typical
      standards committee doubling of the IPv6 address from 64 to
      128 bits, the lunacy of 48 byte cells and the 54 flavors of AAL.
   - no one yet understands how to really make IPv6 or AAL work or even
       play nice with IPv4 during a transition.  (The big unknowns I see
       with both are in application code.  I have some application code
       that is supposed to do both IPv4 and IPv6, but ....)

The differences are
    - IPv6 is tolerates applications that want datagram-like service
    - some relatively minor technical details such as cell overhead
       and stupid ATM switches that didn't drop entire upper layer
       packets when one cell is lost.
    - ATM switches were supposed to be unlike IPv4 routers, or infinitely
       fast and too cheap need purchase orders because the telcos would
       be buying so many of them, but turned out more like telco CO's.
      IPv6 routers are supposed to be just like IPv4 routers.
    - non-technical forces that might actually cause IPv6 to replace IPv4.
       They can be summarized as IPv6 came from the IETF while ATM was
       from the other guys

Vernon Schryver    [email-masked]

---

From: Robert Elz <[email-masked]>
Date: Wed, 23 Aug 2000 00:11:00 +1000

Date:        Tue, 22 Aug 2000 07:48:11 -0600 (MDT)
    From:        Vernon Schryver <[email-masked]>
    Message-ID:  <[email-masked]>

  | Both IPv6 and ATM-to-the-desktop-and-replacing-IP
  |    - require major changes to applications, hosts TCP code, and the boxes
  |        that connect hosts.

The IPv6 changes range between fairly minor and non-existant, depending upon
the application (and when done, result in code that still works over IPv4).

  |    - claim to be desert toppings AND floor waxes

No, IPv6 claims only to be a (really fairly minor) enhancement of IPv4

  |    - suffer standards committee bloat and silliness, such as the typical
  |       standards committee doubling of the IPv6 address from 64 to
  |       128 bits, the lunacy of 48 byte cells and the 54 flavors of AAL.

There were reasons for the address size increase - it should allow just
about anything to autoconfigure successfully - but note we already (still)
have people who claim it isn't big enough.

  | The differences are

ATM requires new hardware (everywhere), IPv6 runs just fine on ancient
hardware (my main stable IPv6 node is a 486 from about a decade ago...
It is stable because it is too slow to do a lot with, I also have it
running on ancient Sun boxes that date from the (late) 80's).  Even assuming
I wanted to run ATM to my desk, I'm not sure it is possible to buy an
interface card that would work for my workstation, I'm certain it wouldn't
be economic.

The two aren't comparable at all in terms of what they're attempting to do,
or what is involved in upgrading from one to another.

kre

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From: Brian E Carpenter <[email-masked]>
Date: Tue, 22 Aug 2000 11:00:57 -0500

Robert ELz made most of the points I'd want to make, but for:

Vernon Schryver wrote:
...
>    - claim much better QoS mechanisms

IPv6 doesn't. IPv6 offers *exactly* the same QOS mechanisms as IPv4,
namely IP Integrated Services and IP Differentiated Services. (There
is also the flow label field in IPv6, but there are as yet no detailed
specs of how it will be used and no false claims either).

...
>       128 bits, 

This was very specifically to enable an adequate (64 bit) locator
component and an adequate (64 bit) identifier component in the address.
And this was based on experience with several datagram network architectures
of the past. The only realistic alternative was variable length addresses.
But since we settled this in 1994, it seems somewhat beside the point.

  Brian

the lunacy of 48 byte cells and the 54 flavors of AAL.

-- 
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Brian E Carpenter 
Program Director, Internet Standards & Technology, IBM 
On assignment for IBM at http://www.iCAIR.org 
Board Chairman, Internet Society http://www.isoc.org
Non-IBM email: [email-masked]

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From: Masataka Ohta <[email-masked]>
Date: Fri, 25 Aug 2000 10:17:14 +0859 ()

Brian;

> namely IP Integrated Services and IP Differentiated Services.

Once, you have been carefully avoiding to say Diffserve offer QoS,
because it does not.

Why are you hyping now?

							Masataka Ohta