Subject: Re: AAAA/A6 thing

From: "David R. Conrad" <[email-masked]>
Date: Mon, 30 Apr 2001 21:04:07 -0700

Jim,

At 10:22 PM 4/30/2001 -0400, Jim Bound wrote:
>With all due respect IPv6 is far superior to IPv4 for renumbering.
>Have you looked in depth at Neighbor Discovery, Stateless
>Autoconfiguration, and Router Renumbering RFCs.  Then put them all
>together.

My understanding that all of these were in a significant state of flux with 
no significant deployment even possible at this time.  I'm glad to hear my 
understanding was mistaken.  Need more time to read...

>Nothing I mean Nothing exists like this in IPv4.

True.  However, IPv4 does, at least, have deployed DHCP which seems to be 
of more interest to larger sites than stateless autoconf.

>We have never said we solved all the renumbering problems.

I don't believe anyone has claimed the problems have been solved.  They are 
difficult problems.  I was under the impression, however, that A6 was 
considered a significant portion of the answer to the renumbering 
problem.  If it is not considered such, then it should be dropped 
immediately as the additional complexity it imposes on the DNS is far too 
high to justify its deployment.

>Nor did we say we would.

For what it is worth (not much, I know), my personal belief is that trivial 
renumbering is key to IPv6's success.  Without it, NAT will have a 
significant advantage, despite NAT's acknowledged problems (no intention of 
sparking yet another NAT flamefest, yes NAT is a blecherous hack).

>The reason IPv6 will be and has begun
>deployment is because of "address space".  Its the primary motivator.

This is worrisome.  By and large, I believe the main reason people are 
unhappy with the current situation with IPv4 is end user sites are normally 
rejected for address allocations of provider independent address space, 
forcing those sites to be dependent on their service provider for address 
space.  The reason for rejection is typically _not_ a lack of address 
space, but rather the RIRs have been put into the position of trying to 
limit the number of provider independent prefixes which enter the routing 
system.

Given the current IPv6 addressing and routing architectures (as I 
understand them -- I'm sure I'll be "gently" corrected if I'm wrong), those 
same end user sites should get rejected for IPv6 space as well -- they 
should go to their service provider for their address space.  Without 
trivial renumbering, those sites that transition to IPv6 will find 
themselves in _exactly_ the same place they are with IPv4, if not 
worse.  They must renumber their site to their new provider's address 
space.  All IPv6's bigger addresses would mean is that they have more to 
renumber.  At that point, why fight the IPv4 inertia?  Why not simply go 
with IPv4 NAT solutions, despite their warts (yes, I know what those warts 
are, but note that I can go down to Office Depot and buy a 56Kbps asynch 
NAT router off the shelf _today_)?

I believe A6 provides a useful generalization that can support greatly 
simplified renumbering.  I also believe a significant amount of operational 
deployment experience is necessary to determine whether or not the 
complexity it imposes on the DNS is justified by the benefits it 
brings.  At least at this point, there are implementations that will permit 
experimentation.  Those experiments should be the focus of efforts, not 
attempts to derail the existence of A6 without supporting evidence.

Rgds,
-drc

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---

From: Bill Manning <[email-masked]>
Date: Mon, 30 Apr 2001 23:38:31 -0700 (PDT)

% 
% Dave,
% 
% With all due respect IPv6 is far superior to IPv4 for renumbering.
% Have you looked in depth at Neighbor Discovery, Stateless
% Autoconfiguration, and Router Renumbering RFCs.  Then put them all
% together.  Nothing I mean Nothing exists like this in IPv4. 

	And it was hell to fix.   Six routers sharing a broadcast domain.
	All running ND & all running RA.  Which Address do the BGP peer
	on?
	The Fix?  Turn off ND & RA and statically configure the interfaces.

-- 
--bill

---

From: Jim Bound <[email-masked]>
Date: Tue, 1 May 2001 08:32:40 -0400 (EDT)

Hi Bill,

> 	The Fix?  Turn off ND & RA and statically configure the interfaces.

Why is BGP affected by ND and RAs.  ND is not for Router-to-Router
communications?

/jim

---

From: Jim Bound <[email-masked]>
Date: Tue, 1 May 2001 08:30:26 -0400 (EDT)

Hi David,

> understanding was mistaken.  Need more time to read...

No flux here.  Router Renumbering is still being built.  But the specs are
very solid.  
 
> of more interest to larger sites than stateless autoconf.

I do agree that Sateful Addrconf must be deployed and folks fought many of
early IPv6 people pretty hard on it.  In DHC WG we hope DHCPv6 will be
wrapped up for London to move to PS status and that will get it done. As
you know there are implementors addressing that requirement now in the
industry and your on that list.  

But this discussion was the abstract regarding Renumbering.  

If your arguing IPv4 is OK and all is well.  Hmmm.  I see not point of
that argument and won't participate as it simply is not OK anymore. 

 > >We have never said we solved all the renumbering
problems. > 
> sparking yet another NAT flamefest, yes NAT is a blecherous hack).

I don't disagree that renumbering is an advantage.  NAT cannot support 3
billion Wireless devices and except for the U.S. none have the address
space to support key end-to-end solutions.  Thats why IPv6 will be
deployed.  There are next steps to renumbering no one is saying there is
not.  But how about a draft instead of just complaining from someone.
I just don't see the benefit of such a discusion for me anyway.

> limit the number of provider independent prefixes which enter the routing 

Same thing.  THe RIRs are trying to manage a scare commodity.
 
> NAT router off the shelf _today_)?

People are free to do that.  We must be talking to different customers the
ones I talk to have had it with this present world and want IPv6 and not
NAT.  But I don't just talk to U.S. Customers either :----) 
But there are some very large U.S. customers that want IPv6 yesterday.

We should fix Multihoming.  But that is not an addressing or routing issue
with IPv6 but something that was not fixed in IPv4 either.  If we fix it
in IPv6 thats another advantage and I think we can.

What exactly in technical terms have you heard is wrong with IPv6
addresses and routing?  Hard for me to defend inuendo......
 
> attempts to derail the existence of A6 without supporting evidence.

I am not arguing about A6 anymore.

regards,
/jim

---

From: Bill Manning <[email-masked]>
Date: Tue, 1 May 2001 05:54:47 -0700 (PDT)

% 
% Hi Bill,
% 
% > % With all due respect IPv6 is far superior to IPv4 for renumbering.
% > % Have you looked in depth at Neighbor Discovery, Stateless
% > % Autoconfiguration, and Router Renumbering RFCs.  Then put them all
% > % together.  Nothing I mean Nothing exists like this in IPv4. 
% > 
% > 	And it was hell to fix.   Six routers sharing a broadcast domain.
% > 	All running ND & all running RA.  Which Address do the BGP peer
% > 	on?
% > 	The Fix?  Turn off ND & RA and statically configure the interfaces.
% > 
% 
% Why is BGP affected by ND and RAs.  ND is not for Router-to-Router
% communications?
% 
% /jim

	BGP is bound between two IP addresses. When the IP addresses change
	the BGP peering is lost.

---

From: Jim Bound <[email-masked]>
Date: Tue, 1 May 2001 08:57:21 -0400 (EDT)

So your saying this happens with router-renumbering?  It should not with
ND.  ND should not alter a peer routers address.  So still why is this an
ND problem.  ND and Router Renumbering are two distinct but compatible
specs?

thanks trying to understand,

/jim

---

From: Bill Manning <[email-masked]>
Date: Tue, 1 May 2001 05:59:06 -0700 (PDT)

Just reporting what happend.  I'll reproduce it when I get back home.

% 
% So your saying this happens with router-renumbering?  It should not with
% ND.  ND should not alter a peer routers address.  So still why is this an
% ND problem.  ND and Router Renumbering are two distinct but compatible
% specs?
% 
% thanks trying to understand,
% 
% /jim
% 
% On Tue, 1 May 2001, Bill Manning wrote:
% 
% > % 
% > % Hi Bill,
% > % 
% > % > % With all due respect IPv6 is far superior to IPv4 for renumbering.
% > % > % Have you looked in depth at Neighbor Discovery, Stateless
% > % > % Autoconfiguration, and Router Renumbering RFCs.  Then put them all
% > % > % together.  Nothing I mean Nothing exists like this in IPv4. 
% > % > 
% > % > 	And it was hell to fix.   Six routers sharing a broadcast domain.
% > % > 	All running ND & all running RA.  Which Address do the BGP peer
% > % > 	on?
% > % > 	The Fix?  Turn off ND & RA and statically configure the interfaces.
% > % > 
% > % 
% > % Why is BGP affected by ND and RAs.  ND is not for Router-to-Router
% > % communications?
% > % 
% > % /jim
% > 
% > 	BGP is bound between two IP addresses. When the IP addresses change
% > 	the BGP peering is lost.
% > 
% > 
% > -- 
% > --bill
% > 
%

---

From: "Matt Crawford" <[email-masked]>
Date: Tue, 01 May 2001 08:49:16 -0500

> 	All running ND & all running RA.  Which Address do the BGP peer

Where does the spec say that routers configure addresses based on
received RAs?  Nowhere.  It says that "Routers respond to Router
Solicitations sent to the all-routers address and verify the
consistency of Router Advertisements sent by neighboring routers."
RFC 2461 section 6.2.7 details the consistency checks and concludes
with "Any other action on reception of Router Advertisement messages
by a router is beyond the scope of this document."

It sounds like someone sold you a bum router implementation.

> 	The Fix?  Turn off ND & RA and statically configure the interfaces.

I do not think you really meant you turned off Neighbor Solicitations
and Neighbor Advertisements and staticly configured the Neighbor
Caches.  You could do that, but I can't imagine such a necessity.
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---

From: Bill Manning <[email-masked]>
Date: Tue, 1 May 2001 07:31:42 -0700 (PDT)

% with "Any other action on reception of Router Advertisement messages
% by a router is beyond the scope of this document."
% 
% It sounds like someone sold you a bum router implementation.

	Sold? Not so. Still working with early release code
	from a number of vendors. Looks like more work still needs
	to be done to declare this "cooked".

---

From: [email-masked]
Date: Wed, 02 May 2001 02:14:13 +0900

>> 	All running ND & all running RA.  Which Address do the BGP peer

	from the above I don't know if Bill have autoconfigured routers...
	did you?

	anyway, i guess there's a separate issue - what is the best address
	to be used for BGP peering at random IXes.  is it what you are
	talking about?

	my bet is that link-local address (for tcp endpoint address) has
	the best resistance against renumber or other events, however,
	there are implementations that cannot do this.  also it may conflict
	with Francis' BGP4+ RFC (but the RFC is not too clear about separation
	between tcp/179 endpoint address, and nexthop values - at least for me)

	there also are IXes that use globally-reachable IPv6 prefix, curved
	out from one of the adjacent ASes.  for example, NSPIXP6 uses
	a /64 prefix from WIDE.

	there are people using addresses that are not reachable from outside,
	as i have pointed out in the following.  PAIX is using a /32 got from
	ISI, however, the prefix used at PAIX is not reachable from outside
	if we filter routes based on 6bone routing guideline.
	not sure if it is a real problem or not.

To: [email-masked]
Subject: reachability issue with 3ffe:80a::/32 (PAIX IX segment)
From: Jun-ichiro itojun Hagino <[email-masked]>
Date: Wed, 17 Jan 2001 21:13:59 +0900
Message-Id: <[email-masked]>
Sender: [email-masked]

itojun

---

From: "David R. Conrad" <[email-masked]>
Date: Tue, 01 May 2001 12:54:54 -0700

Jim,

At 08:30 AM 5/1/2001 -0400, Jim Bound wrote:
>If your arguing IPv4 is OK and all is well.  Hmmm.

No, and I'm not sure how you'd come to this conclusion from what I 
said.  I'm arguing that renumbering is "Very Important" and is one area in 
which IPv6 could conceivably provide a reasonable justification for the 
pain of undertaking the transition.  More address space ain't gonna do it 
if the ISPs of the world say "I can't route your prefix, renumber into 
mine" as they MUST if we expect IPv6 to scale beyond what IPv4 scales to.

>Same thing.  THe RIRs are trying to manage a scare commodity.

No.  The statement Itojun made was that larger address space was the 
primary justification for IPv6.  Larger address space CONTRIBUTES to the 
problem that the RIRs are trying to help manage, namely the proliferation 
of globally routable prefixes.  IPv6, as it is currently defined, does NOT 
address the _REAL_ problem, namely routable prefix growth.  It threatens to 
exacerbate the problem greatly as the swamp of end-user globally routed 
IPv6 address is so much larger.

Having workable renumbering would help greatly in reducing routable prefix 
growth.  Whereas A6 supports renumbering, it is a good thing and 
experiments should be undertaken to determine if it actually helps (and 
just how it can be made to help).

>addresses and routing?

Nothing that isn't wrong with IPv4, and that's sort of the 
point.  Renumbering is hard and multi-homing implies de-aggregation.  IPv6 
routing and addressing as it is currently defined does nothing to solve 
these problems as far as I can tell.

Rgds,
-drc

---

From: Francis Dupont <[email-masked]>
Date: Wed, 02 May 2001 09:16:48 +0200

In your previous mail you wrote:

=> this (link-local address idea) has two restrictions:
 - it doesn't work with off-link peers (i.e. with iBGP and multi-hop
   eBGP)
 - it doesn't work if the same address is used on more than a link
   (i.e. you have no scope ID to distinguish peers).

=> no, BGP4+ is clear and flexible: it addresses only the real issue
(next-hop), not the transport issue (which needs only  simple properties
like reachability and local unicity of the peer address).

=> this discussion occurs one more time yesterday at the RIPE meeting.
There was no general concensus but it seems that global addresses are
strictly better than local scoped addresses. Of course the problem to
get these global addresses was (i.e. is :-) still open. Personally
I think an address has no value by itself so the key is to route
the addresses and a solution is to get addresses from ISPs (IXP members)
which accept to announce/route IXP addresses (i.e. the IXP is a  special
case  of a multi-homed routing domain). Some others wanted a special block
of independent addresses for IXPs...

Regards

[email-masked]

---

From: Jim Bound <[email-masked]>
Date: Wed, 2 May 2001 06:49:54 -0400 (EDT)

Bill,

As you check this out further please make sure the early adopter systems
are in fact running the new product versions shipped from several of us.
If they are broken send in a QAR or Bugreport as IPv6 is now "product" on
a lot of boxes.  We also have implementors list for this too.

thanks

/jim

---

From: Paul A Vixie <[email-masked]>
Date: Tue, 01 May 2001 00:28:21 -0700

> 	The Fix?  Turn off ND & RA and statically configure the interfaces.

the idea of using any kind of stateless automatic *anything* with bgp speaking
routers....... terrifies me.  at paix, for ipv6, we statically allocate.

---

From: "Matt Crawford" <[email-masked]>
Date: Wed, 02 May 2001 18:27:01 -0500

> the idea of using any kind of stateless automatic *anything* with
> bgp speaking routers....... terrifies me.  at paix, for ipv6, we
> statically allocate.

I have already pointed out the parts of the ND spec that say that
routers should not be autoconfiguring addresses from received router
advertisements.  Bill was just suffering a little early-adopter pain
with unfinished router implementations.

---

From: Jim Bound <[email-masked]>
Date: Thu, 3 May 2001 00:17:52 -0400 (EDT)

Dave,

We drift.  I will agree that we need further work on renumbering.  I will
agree that we need further work on the partitioning of the 128bits.  We do
need to some new things for Multihoming.  As far as autonconfiguration in
IPv6 that has been preached say one and I also implemented that code and
its shipping in a product.  

Just don't tell me we have nothing now cause that is simply false.

As far as address space I hear you.  But your arguing from the operator
view.  The end user view for 3G wireless and a few other industries I
cannot mention do want global address space and are large enough to be
their own Providers.

I think we are in violent agreement.  Other stuff I got to say I will say
privately thats between you and me.

thanks

/jim

---

From: Bill Manning <[email-masked]>
Date: Thu, 3 May 2001 05:41:11 -0700 (PDT)

% 
% > > 	The Fix?  Turn off ND & RA and statically configure the interfaces.
% > 
% > the idea of using any kind of stateless automatic *anything* with
% > bgp speaking routers....... terrifies me.  at paix, for ipv6, we
% > statically allocate.
% 
% I have already pointed out the parts of the ND spec that say that
% routers should not be autoconfiguring addresses from received router
% advertisements.  Bill was just suffering a little early-adopter pain
% with unfinished router implementations.

	Matt, writing a spec does not an implementation make.
	While a static delegation may be made by the manager of
	the exchange address space, they do not control the 
	software load of the client... and thats the part that
	gives me the willies.

---

From: Bill Manning <[email-masked]>
Date: Mon, 7 May 2001 03:43:00 -0700 (PDT)

% 
% >> 	And it was hell to fix.   Six routers sharing a broadcast domain.
% >> 	All running ND & all running RA.  Which Address do the BGP peer
% >> 	on?
% 
% 	from the above I don't know if Bill have autoconfigured routers...
% 	did you?

	Yes. This involved a number of boxes. (see the recent thread on
	host/router)  
 
% 	anyway, i guess there's a separate issue - what is the best address
% 	to be used for BGP peering at random IXes.  is it what you are
% 	talking about?

	Not really. Although there is discussion on what constitutes 
	appropriate RIR policy for IX use. 

% 	my bet is that link-local address (for tcp endpoint address) has
% 	the best resistance against renumber or other events, however,
% 	there are implementations that cannot do this.  also it may conflict
% 	with Francis' BGP4+ RFC (but the RFC is not too clear about separation
% 	between tcp/179 endpoint address, and nexthop values - at least for me)

	Too many problems there. IX'en really need global space.

% 	there are people using addresses that are not reachable from outside,
% 	as i have pointed out in the following.  PAIX is using a /32 got from
% 	ISI, however, the prefix used at PAIX is not reachable from outside
% 	if we filter routes based on 6bone routing guideline.
% 	not sure if it is a real problem or not.

	The 6bone routing guideline is oriented toward ISPs, as are the RIR
	delegations practices. IX'en are different than ISPs and so the ISP
	rules applied to IX'en often break.

% 
% To: [email-masked]
% Subject: reachability issue with 3ffe:80a::/32 (PAIX IX segment)
% From: Jun-ichiro itojun Hagino <[email-masked]>
% Date: Wed, 17 Jan 2001 21:13:59 +0900
% Message-Id: <[email-masked]>
% Sender: [email-masked]
% 
% itojun
%

---

From: [email-masked]
Date: Mon, 07 May 2001 20:12:04 +0900

>	Yes. This involved a number of boxes. (see the recent thread on

	(as there were many comments) RFC2462 is just for hosts, not for
	routers.

>	Too many problems there. IX'en really need global space.

	could you list some of the problems?  the only issue I see is the
	possible non-uniqueness of 128 bit address (as pointed out by Francis).

>	rules applied to IX'en often break.

	...therefore I tried to propose a written rule for IX prefix assignment
	in the following email (like "you should accept /32 routes under
	3ffe:800::/24").  do you have any comments?

itojun

---

From: Bill Manning <[email-masked]>
Date: Mon, 7 May 2001 11:20:30 -0700 (PDT)

% 
% >% 	from the above I don't know if Bill have autoconfigured routers...
% >% 	did you?
% >	Yes. This involved a number of boxes. (see the recent thread on
% >	host/router)  
% 
% 	(as there were many comments) RFC2462 is just for hosts, not for
% 	routers.

	But, as the discussion pointed out, the IPv6 concept of "host"
	vs "router" may be done on a per-interface basis. As you mentioned,
	you found this to be a bit too flexable and refined this based on
	operational issues.

% >	The 6bone routing guideline is oriented toward ISPs, as are the RIR
% >	delegations practices. IX'en are different than ISPs and so the ISP
% >	rules applied to IX'en often break.
% 
% 	...therefore I tried to propose a written rule for IX prefix assignment
% 	in the following email (like "you should accept /32 routes under
% 	3ffe:800::/24").  do you have any comments?

	This is an active area of discussion, at least in the RIPE and
	ARIN communities and I expect that we should divert further discussion
	there. (for ARIN,  <[email-masked]> is the venue)