Subject: [RRG] LISP, IPv6 and 6to4

From: "Templin, Fred L" <[email-masked]>
Date: Thu, 6 Dec 2007 18:55:35 -0800

I am wondering why there hasn't been more discussion about
using LISP as the vehicle to get us to IPv6, e.g. by having
EIDs as IPv6 addresses and RLOCs as IPv4 addresses from the
onset. A hallway discussion brought up the subject of
incremental deployment, but why can't we just use 6to4
as the bootstrapping vehicle to get us to LISP/IPv6?

By this, I mean that nodes having 2002::/16 EIDs are handled
using 6to4 and have the same deployment profile as for 6to4
today. Then, we require that nodes having non-6to4 EIDs be
deployed behind ETRs. If we then also say that 6to4 relay
routers must configure themselves as ITRs and do the necessary
map-and-encaps, we have an incremental deployment profile.

Any thoughts on this?

Fred
[email-masked]

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From: Tony Li <[email-masked]>
Date: Thu, 6 Dec 2007 22:56:58 -0800

> map-and-encaps, we have an incremental deployment profile.

Fred,

Could such a host access IPv4 sites?

Tony

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From: "Templin, Fred L" <[email-masked]>
Date: Fri, 7 Dec 2007 09:28:06 -0800

Tony,

> Could such a host access IPv4 sites?

Sure; IMHO, leave the IPv4 Internet in-place and (as someone
once articulated to me) "build a second story" on top of the
existing foundation.

Fred

> -----Original Message-----
> From: Tony Li [mailto:[email-masked]] 
> Sent: Thursday, December 06, 2007 10:57 PM
> To: Templin, Fred L
> Cc: [email-masked]
> Subject: Re: [RRG] LISP, IPv6 and 6to4
> 
>

---

From: Tony Li <[email-masked]>
Date: Fri, 7 Dec 2007 09:33:19 -0800

Fred,

Where did you hide the NAT-PT box?  And, once you have the NAT-PT  
box, why do you need LISP involved?

Tony

---

From: "Templin, Fred L" <[email-masked]>
Date: Fri, 7 Dec 2007 09:44:10 -0800

Tony,

> Sent: Friday, December 07, 2007 9:33 AM
> To: Templin, Fred L
> Cc: [email-masked]

I'm not sure it needs to be NAT-PT due to dual stack and/or
IPv4-in-IPv6 tunneling, but if NAT-PT were used then I don't
know why it wouldn't be co-located on the ITR.

There was an entire discussion session in v6ops yesterday
on tunneling vs translation that involved much more-informed
individuals than myself, and AFAICT there were no conclusions.
So, it would be wrong for me to hazard a guess as to which way
is better at this point.

Thanks - Fred

---

From: "Templin, Fred L" <[email-masked]>
Date: Fri, 7 Dec 2007 10:16:12 -0800

Tony,

I guess I will have just one more word on this. If the LISP
sites are organized as dual-stack nodes that have IPv6 addresses
that appear as EIDs for LISP, but use IPv4 private addresses for
the site-internal organization, then there is dual-stack and no
need for NAT-PT.

This is exactly the use case scenario for ISATAP.

Fred

> From: Templin, Fred L 
> Sent: Friday, December 07, 2007 9:44 AM
> To: Tony Li
> Cc: [email-masked]
> Subject: RE: [RRG] LISP, IPv6 and 6to4
> 
> Tony,
>

---

From: "Templin, Fred L" <[email-masked]>
Date: Fri, 7 Dec 2007 10:52:05 -0800

Tony,

> know why it wouldn't be co-located on the ITR.

So then another final remark, NAT-PT boxes belong on the
site border routers of IPv6-only sites. That's about it,
I think.

Thanks - Fred

---

From: Brian E Carpenter <[email-masked]>
Date: Sun, 09 Dec 2007 08:46:24 +1300

> map-and-encaps, we have an incremental deployment profile.

(Having also read your exchanges with Tony.)

I'm not sure why we would need to do this. Sure, it maintains
the 6to4 primary goal of *not* importing IPv4 DFZ entropy
into the future DFZ, but why does it help us deploy IPv6,
compared with just deploying IPv6? When we run out of IPv4
prefixes three years from now, the incentive to use 6to4 as
a deployment mechanism will fade, and the incentive will be
the availability of native IPv6 prefixes. (I have little doubt
that LISP will be able to enfold IPv6 easily enough when
the time comes.)

     Brian

---

From: "Templin, Fred L" <[email-masked]>
Date: Mon, 10 Dec 2007 10:30:28 -0800

Brian, 

> From: Brian E Carpenter [mailto:[email-masked]] 
> Sent: Saturday, December 08, 2007 11:46 AM
> To: Templin, Fred L
> Cc: [email-masked]
> compared with just deploying IPv6?

Consider that incremental 6to4 deployment is already under
way under the 2002::/16 prefix space. The deployment includes
6to4 relay routers that relay traffic from the 2002::/16 prefix
space to reach nodes in sites that configure non-2002::/16
prefixes. With this incremental deployment already under way,
we could say that:

  - new sites that deploy native IPv6 prefixes (i.e., prefixes
    other 2001::/16 and 2002::/16) must also deploy ITR/ETRs
    at their outermost borders and must support a map/encaps
    scheme like LISP/APT
  - 6to4 relay routers must be configured to also act as ITRs
    so that nodes in 6to4-only sites will be able to reach
    nodes in non-6to4 sites, i.e., they must be configured
    as LISP/APT proxy tunnel routers
  - 6to4-only sites should begin to deploy ITR/ETRs, at which
    point they can begin to deploy native IPv6 prefixes and
    phase out 6to4

So, as you say below, 6to4 use would eventually fade, and
a full LISP/APT IPv6 Internet would result with ITR/ETRs
everywhere. (All of this IMHO, of course.)

Fred
fred.l.templin@boeing.

> When we run out of IPv4

---

From: Dino Farinacci <[email-masked]>
Date: Mon, 10 Dec 2007 10:56:58 -0800

> everywhere. (All of this IMHO, of course.)

Fred, as we mentioned in the Tutorial and RRG meetings, we could use  
IPv6 EIDs and IPv4 locators and have site-based IPv6 packets get  
encapsulated in IPv4. We could do a mapping lookup to translate from a  
IPv6 EID to a IPv4 locator, or to be 6to4 address aware get the IPv4  
locator from the 2002::/16 prefix and avoid the mapping lookup.

Having said that, it would not give us multi-homing support for the  
IPv6 destination site, but if you used the 2002::/16 locator as an  
anycast address for more than one ETR at the destination IPv6 site,  
then closest entrance policy would be used by any source IPv6 site.

But if you have a mapping database deployed, you may as well use it  
and get the features that come along with it. So I see little value in  
using the 2002::/16 embedded IPv4 address as a locator.

Dino

---

From: "Templin, Fred L" <[email-masked]>
Date: Mon, 10 Dec 2007 12:18:37 -0800

Dino,

> using the 2002::/16 embedded IPv4 address as a locator.

I think we agree, and all I am saying is that legacy
6to4 sites that do not yet have ITR/ETR nor a mapping
capability can continue to use 6to4 until they do.
With the 6to4 relay router acting as proxy ITR/ETR, I
still see 6to4 as an incremental deployment vehicle
toward full native IPv6 LISP/APT/etc. (Thereafter,
6to4 can fade away as you and Brian have said.)

Fred