Subject: RE: draft-ietf-ipv6-ula-central-02.txt

From: <[email-masked]>
Date: Sun, 1 Jul 2007 15:00:02 +0100

> My main question about ULA-C still stands: how is it 
> different from PI?

To understand the difference between PI and ULA-C you need to understand
the difference between the public Internet and an IP internetwork. Any
set of networks that use the Internet Protocols are an IP internetwork.
However there is only one public Internet and that is the subset of IP
internetworks which have chosen to connect together so that end hosts
can communicate without prior arrangements.

PI addresses are public Internet addresses which end hosts can use to
communicate without prior arrangements. ULA-C addresses can only be used
to communicate between end hosts where both ends have made prior
arrangements to enable communication between the two ULA-C blocks from
which the end-hosts are numbered. Any IP internetwork managed by a
single authority can make use of ULA-C addresses because the single
authority presumably is in charge of making things work. When two or
more authorities who manage internetworks wish to enable inter-authority
(inter-AS) communication, they need to make specific arrangements either
bilaterally or unilaterally. 

These arrangements are a lot like Internet peering arrangements
although, technically, it is not necessary to use ASes and BGP4 to do
this, just hook things up with circuits or tunnels. What is missing in
this ULA-C picture is transit. On the public Internet there is the
assumption that packets will be carried across as many autonomous
networks as necessary to reach their destination. However, when the
source address or destination address is ULA-C, the transit assumption
breaks down. There is no "assumed" interconnectivity with ULA-C
addresses which makes them quite different from PI addresses.

There will be some groups of organizations who find the requirement for
making prior arrangements to be very useful. They may not want any
packets from sources who have not signed a mutual agreement. These
Community Of Interest Networks exist today in the IPv4 world and they
are thriving. Examples are the auto industry with ANX and ENX, the air
transport industry with Aeronet and the global financial services
industry with RadianzNet. 

I am not suggesting that any of these existing networks would use ULA-C
but that they represent real-world use-cases for globally unique
registered address space that is explicitly *NOT* routed on the public
Internet. The big question here is whether ULA-C presents any advantage
over simply using PI and selectivly shutting off the characteristics
which are not desirable. For instance, if you never announce your PI
prefix on the Internet, then you will never receive any packets without
prior arrangement.

--Michael Dillon

P.S. if anyone has other examples besides automotive, air transport and
financial services idustries, I would be interested in hearing about
them.

--------------------------------------------------------------------
IETF IPv6 working group mailing list
[email-masked]
Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6
--------------------------------------------------------------------

---

From: <[email-masked]>
Date: Sun, 1 Jul 2007 16:53:34 +0100

> A site is a network of computers with a single 
> administration, this can mean indeed a major corporation (who 
> maybe even require multiple /48's which is why rfc4193 is a 
> bit off to cover those cases)

Where has the IETF redefined the meaning of the word "site"?
In plain English, this word refers to a distinct physical location such
as an office or building or campus.

--Michael Dillon

---

From: Brian E Carpenter <[email-masked]>
Date: Mon, 02 Jul 2007 10:59:12 +0200

> as an office or building or campus.

That's true, in plain English. However, as the agonising over
deprecating site-local showed, it doesn't quite work in the
Internet since corporate intranets arose. So it has certainly
been used in IPv6 discussions for anything from a dentist's
office network up to a corporate network with multiple
physical sites and multiple interconnects to the Internet.
I think that's why the word "site" is not part of the
name of a ULA. It creates confusion.

     Brian

---

From: "Stephen Sprunk" <[email-masked]>
Date: Thu, 12 Jul 2007 12:41:32 -0500

Thus spake <[email-masked]>
>> A site is a network of computers with a single administration,
>> this can mean indeed a major corporation (who maybe even
>> require multiple /48's which is why rfc4193 is a bit off to cover
>> those cases)
>

This has been a longstanding problem in the IETF; in fact, the inability to 
agree on what "site" means was one of the reasons SLAs were deprecated.  The 
word "site" is often abused to mean "administrative domain" rather than 
"physical location" due to the ISP-centric nature of the IETF and RIRs. 
It's virtually impossible to tell, in any particular context, which meaning 
an author meant.  We need to stop using the word entirely...

S

Stephen Sprunk      "Those people who think they know everything
CCIE #3723         are a great annoyance to those of us who do."
K5SSS                                             --Isaac Asimov

---

From: Roger Jorgensen <[email-masked]>
Date: Fri, 13 Jul 2007 12:04:16 +0200 (CEST)

On Thu, 12 Jul 2007, Stephen Sprunk wrote:
> "physical location" due to the ISP-centric nature of the IETF and RIRs. It's 
> virtually impossible to tell, in any particular context, which meaning an 
> author meant.  We need to stop using the word entirely...

why does it mather if it is physical site, administrative domain (eh how 
can anyone interprent that as a site?!) or a room, company etc... why not 
leave that upto those that try to use it?

-- 

------------------------------
Roger Jorgensen              | - ROJO9-RIPE  - RJ85P-NORID
[email-masked]           | - IPv6 is The Key!
-------------------------------------------------------

---

From: Paul Vixie <[email-masked]>
Date: Fri, 13 Jul 2007 14:24:56 +0000

> >>> A site is a network of computers with a single administration, ...

> >> Where has the IETF redefined the meaning of the word "site"? ...

> > This has been a longstanding problem in the IETF; in fact, the inability
> > to agree on what "site" means was one of the reasons SLAs were ...

> why does it mather if it is physical site, administrative domain ...

indeed, from the rfc that was quoted at me when i asked about this a month
ago, it appears that "site" is meant as "usually the same thing as an
autonomous system but can mean something else if you want it to."

---

From: Jeroen Massar <[email-masked]>
Date: Fri, 13 Jul 2007 15:41:04 +0100

[cross cc'd to v6ops as this sounds more like a ops thing]

> autonomous system but can mean something else if you want it to."

From what I understand at least RIPE NCC is using the meaning along the
lines of "A network with the same administrative domain confined to a
single or a group of buildings".

As such a site could be (amongst others):
 - a host in a datacenter which provides VPN's to other sites
   over its own link.
 - a home network, eg where a DSL or cable line or a PPP link terminates
 - an office in a home network where a VPN/PPP/DSL terminates
 - a big office complex, where the network is run by an admin group
   who have an incoming 1Gbit/s link
 - multiple buildings around a city/country/world all linked
   together with VPN using one single /48, but eg a /56 per building.

And various other cases. Note that I add the way the network gets
connected to the rest of the world. Of course there are cases where one
does not link up to the Internet or even to other sites.

I am pretty sure that the various RIR's are well known enough with a
definition that they handle consistently in their region, which in one
way or the other most likely matches the above.

Maybe somebody should write a mini-RFC labeled "What is a site" and
include some examples to show exactly how/what? Guess it would fit in
perfectly for the v6ops WG (cross cc'd for that purpose).

Greets,
 Jeroen

---

From: "Templin, Fred L" <[email-masked]>
Date: Fri, 13 Jul 2007 08:19:53 -0700

In 'draft-templin-autoconf-dhcp-08.txt', I define site as:

   "Mobile Ad-hoc Network (MANET)
      a connected network region of MANET routers that maintain a
      routing structure among themselves over MANET interfaces.  A MANET
      may be as large as an Autonomous System (AS) or as small as a
      single MANET router, and may also be a subnetwork of a larger
      MANET.  A MANET router (and its attached networks) is a "site"
      unto itself, and a MANET is therefore a "site-of-sites".  (Note
      that this document considers the terms "MANET" and "site" as
      functional equivalents.)"

Thanks - Fred
[email-masked] 

> -----Original Message-----
> From: Jeroen Massar [mailto:[email-masked]] 
> Sent: Friday, July 13, 2007 7:41 AM
> To: Paul Vixie
> Cc: IETF Ops; [email-masked]
> Subject: What is a site (Re: draft-ietf-ipv6-ula-central-02.txt)
> 
> administration, ...

---

From: "Stephen Sprunk" <[email-masked]>
Date: Fri, 13 Jul 2007 11:16:58 -0500

Thus spake "Roger Jorgensen" <[email-masked]>
>> This has been a longstanding problem in the IETF; in fact,
>> the inability to agree on what "site" means was one of the
>> reasons SLAs were deprecated.  The word "site" is often
>> abused to mean "administrative domain" rather than "physical location" 
>> due to the ISP-centric nature of the IETF
>> and RIRs. It's virtually impossible to tell, in any particular
>> context, which meaning an author meant.  We need to stop
>> using the word entirely...
>
> why does it mather if it is physical site, administrative domain
> (eh how can anyone interprent that as a site?!) or a room,
> company etc... why not leave that upto those that try to use it?

It matters because there are a lot of protocol and policy documents that 
refer to "sites".  For instance, one of the current qualifications for 
getting an IPv6 LIR allocation require that one have a plan to make 
assignments to 200 "sites".  Obviously the meaning of that is significantly 
changed depending on whether you consider a single company with 200+ 
locations sharing a single uplink to be one "site" or 200+ "sites".

Also, in the case of SLAs, the utility of the addresses is impacted greatly 
by whether you consider a "site" to be a single administrative domain, where 
there would not be internal collisions, vs. considering each distinct 
location to be a "site", which could lead to hundreds or thousands of 
internal collisions.

As far as why "site" has been abused to mean "administrative domain", that 
comes from the IETF and RIRs being very ISP-centric, as I said; a single 
downstream connection denotes a single "site" regardless of how complex the 
internal network behind it is or how many other locations it serves.  Or 
maybe it doesn't, depending on who's talking; that's the problem.

S

---

From: Roger Jorgensen <[email-masked]>
Date: Fri, 13 Jul 2007 21:24:05 +0200 (CEST)

On Fri, 13 Jul 2007, Stephen Sprunk wrote:
>>> abused to mean "administrative domain" rather than "physical location" due 
>>> to the ISP-centric nature of the IETF

if you refair to RIPEs policy it has just been changed,
"Consensus has been reached on the proposal described in 2006-02 and
it is accepted by the RIPE community.

This proposal is to change the IPv6 Initial Allocation criteria and
the End Site definition in the "IPv6 Address Allocation and
Assignment Policy".

You can find the full proposal at:

    http://www.ripe.net/ripe/policies/proposals/2006-02.html
"

> location to be a "site", which could lead to hundreds or thousands of 

I can not see how SLAs are any of this wg's business, or ietfs businness. 
thought SLA was something for the laywers that write the contracts 
governing any SLAs to fight out between them?

> maybe it doesn't, depending on who's talking; that's the problem.

that downstream connection is ONE site for the upstream provider, will 
probably never be anything else. Why should it be anything else really? If 
the same "site" bought two connection to an ISP on different location they 
would still be one huge site, with several internal parts, two that the 
ISP need to know about.

What I'm not sure you realize is that the moment anyone define a site to 
be something very specific... there will come alot of exceptions to that 
list, not to forget discussion on how to interprent whats written there. 
It is way easier to say site and leave it with that... and maybe, just 
maybe list a few examples and leave it upto those that have to use the 
word site to agree between them.

--

---

From: <[email-masked]>
Date: Fri, 13 Jul 2007 20:28:32 +0100

> As far as why "site" has been abused to mean "administrative 
> domain", that comes from the IETF and RIRs being very 
> ISP-centric, as I said; a single downstream connection 
> denotes a single "site" regardless of how complex the 
> internal network behind it is or how many other locations it 
> serves.  Or maybe it doesn't, depending on who's talking; 
> that's the problem.

I have always believed that the definition of a site in IPv6 is tied in
with the idea that if every "site" has a /48 subnet assignment, then
migration to a different provider only requires changing the prefix
bits. The existing subnet topology hidden inside the /48 remains
unchanged.

By this definition an apartment or family home is a site. An office in
big buidling is a site. A company building is a site. A campus-like
collection of buildings is a site. Here is where definitions need to be
precise and relate back to original goals.

A single company may own several buildings and those buildings may be
next to each other. I believe that each separate building should be
considered to be a site. A campus is more than a collection of buildings
because it is difficult, or impossible to separate one building from the
group. On a campus there is centralization of utilities, even going so
far as to connect all buildings by tunnel systems and heat all buildings
via hot water from a central steam plant.

Why is the definition of a site so important? Because a "site" is
mobile. It can change providers and it can change ownership indpendent
of neighboring sites. By that definition, airplanes, trucks and train
carriages are also sites. They are just mobile more frequently than
sites in buildings.

I think it is important for the IETF to have clear documentation of the
interconnectedness of "sites", /48 prefixes, mobility, and freedom of
choice.

At least one RIR now allows ISPs to assign shorter /56 prefixes to
consumer sites, i.e. family homes and apartments. This is not
necessarily a bad thing since it is rare for a family home to turn into
an office without significant infrastructure change. But if there is to
be a special size for the family home, it too should be the same
worldwide. And it too should be documented by the IETF.

--Michael Dillon

---

From: "Stephen Sprunk" <[email-masked]>
Date: Sat, 14 Jul 2007 10:18:35 -0500

>> Also, in the case of SLAs, the utility of the addresses is
>> impacted greatly by whether you consider a "site" to be a
>> single administrative domain, where there would not be
>> internal collisions, vs. considering each distinct location
>> to be a "site", which could lead to hundreds or thousands
>> of internal collisions.
>
> I can not see how SLAs are any of this wg's business, or ietfs
> businness.  thought SLA was something for the laywers that
> write the contracts governing any SLAs to fight out between
> them?

Site-Local Addresses, the predecessor to Unique Local Addresses.

>> domain", that comes from the IETF and RIRs being very ISP-
>> centric, as I said; a single downstream connection denotes a
>> single "site" regardless of how complex the internal network
>> behind it is or how many other locations it serves.  Or maybe
>> it doesn't, depending on who's talking; that's the problem.
>
> that downstream connection is ONE site for the upstream
> provider, will probably never be anything else. Why should it
> be anything else really? If the same "site" bought two
> connection to an ISP on different location they would still be
> one huge site, with several internal parts, two that the ISP need to know 
> about.

No, that's one interpretation of the word.  Others (notably the person I was 
responding to) consider every physical location to be a "site" even if a 
large set of locations all share a single internal network and single 
uplink.

> What I'm not sure you realize is that the moment anyone define
> a site to be something very specific... there will come alot of
> exceptions to that list, not to forget discussion on how to
> interprent whats written there.

We already have extensive disagreement on interpretation due to lack of any 
agreed-upon definition.

S

---

From: Brian E Carpenter <[email-masked]>
Date: Mon, 16 Jul 2007 09:53:30 +0200

On 2007-07-13 18:16, Stephen Sprunk wrote:
...
> As far as why "site" has been abused to mean "administrative domain", 
> that comes from the IETF and RIRs being very ISP-centric, as I said; a 
> single downstream connection denotes a single "site" regardless of how 
> complex the internal network behind it is or how many other locations it 
> serves.  Or maybe it doesn't, depending on who's talking; that's the 
> problem.

I think another reason we've often expanded the meaning of 'site' is
because the IETF has never come to grips with the fact that most
multi-site companies (in the geographical sense) have intranets that
interconnect those sites and are multiply connected to the Internet.
Since we don't have an IETF term for such topologies, apart from AS,
we confuse ourselves.

On 2007-07-13 21:28, [email-masked] wrote:
...
> interconnectedness of "sites", /48 prefixes, mobility, and freedom of

We should certainly provide technology that allows freedom of choice,
but the IETF can't do more than that.

> worldwide. And it too should be documented by the IETF.

Actually the IAB tried (RFC 3177) and the RIRs chose another
approach, which is where /56 comes from.

     Brian