Subject: [RRG] Consensus check: renumbering

From: "Tony Li" <[email-masked]>
Date: Fri, 22 Aug 2008 17:41:26 -0700

Hi all,

The discussion surrounding renumbering has slowed a bit, so I'd like to get=
 a sense of where we stand.

Assuming current renumbering technology, what amount of renumbering can be =
required in the RRG's recommended routing architecture?

Please respond here:
http://www.doodle.ch/participation.html?pollId=3Dziu439pxxpcx33da

Thanks,
Tony

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From: [email-masked] (Noel Chiappa)
Date: Fri, 22 Aug 2008 20:52:14 -0400 (EDT)

> From: "Tony Li" <[email-masked]>

    > Assuming current renumbering technology, what amount of renumbering
    > can be required in the RRG's recommended routing architecture?

I think you need to be a little more specific in here, specifically, in
which namespaces? I think the answer will be rather different for location
and identity namespaces. Did you want to modify your question to be "what
amount of renumbering _in the identification namespace_ can be required"?

	Noel

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From: "Tony Li" <[email-masked]>
Date: Fri, 22 Aug 2008 18:26:52 -0700

|I think you need to be a little more specific in here, specifically, in
|which namespaces? I think the answer will be rather different 
|for location
|and identity namespaces. Did you want to modify your question 
|to be "what
|amount of renumbering _in the identification namespace_ can be 
|required"?

Noel,

I don't think that end users will care one whit about which namespace
they're renumbering.  The work's the same.  ;-)

I also don't want to get into the entire debate about whether map-n-encap
really uses an inner identifier or whether it's just a VPN address...

Tony

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From: [email-masked] (Noel Chiappa)
Date: Sat, 23 Aug 2008 11:40:20 -0400 (EDT)

>> Did you want to modify your question to be "what amount of renumbering
    >> _in the identification namespace_ can be required"?

    > they're renumbering. The work's the same. ;-)

Well, no it's not, actually - which is one of the chief points of having more
than one namespace.

(Since we all agree that a site which is only a small piece of the entire
connectivity graph needs to renumber its location-names when it switches to a
different ISP^H^H^H connectivity point to the graph, then if it were equally
easy to renumber location-names and identity-names, then one might as well
just go ahead and renumber the identity-names, right?)

The exact details of _how_ much easier/harder it will be depend on the exact
details of the scheme, of course.

E.g. as someone (Iljistch? - sorry in advance if my memory is failing me on
that) pointed out, NAT allows you to avoid renumbering _inside_ the site, but
still require renumbering everything _outside_ the site. With LISP and
similar schemes, you have to update the mapping table, but depending on what
external stuff is configured to use, you may be able to avoid any other
changes (e.g. if other sites filter on the EID and not the RLOC - I hope I
got that jargon right - you could avoid updating foreign filters). Etc, etc.

	Noel

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From: Olivier Bonaventure <[email-masked]>
Date: Sat, 23 Aug 2008 21:19:56 +0200

Tony,
> they're renumbering.  The work's the same.  ;-)

I agree with Noel. The answer to your poll will not be the same if we 
consider identifiers or locators. I expect that renumbering locators 
will be much easier than renumbering identifiers.

Olivier

-- 
http://inl.info.ucl.ac.be , UCLouvain, Belgium

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From: "Tony Li" <[email-masked]>
Date: Sat, 23 Aug 2008 15:39:17 -0700

Hi Noel,

|    > I don't think that end users will care one whit about 
|which namespace
|    > they're renumbering. The work's the same. ;-)
|
|Well, no it's not, actually - which is one of the chief points 
|of having more
|than one namespace.

Let me come at this from a different perspective: the truly painful event
that is the large issue for folks like Eric is the prospect of having to
reconfigure each and every host within the site.  This is work that scales
linearly or super-linearly with the size of the site.

To the site administrators, whether they are changing IPv4 addresses, IPv6
addresses, FQDN's or public/private key pairs, the pain is pretty much the
same.  Touching everything *hurts*.

That said, yes, for most schemes this event happens when you renumber the
identifier namespace.  However, I really don't want to get hung up on which
namespace it is that causes this level of pain.

Is this sufficient clarification?  If not, care to propose a wording change?

Tony

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From: Scott Brim <[email-masked]>
Date: Sun, 24 Aug 2008 09:12:37 -0400

> linearly or super-linearly with the size of the site.

Well,

  - changing the locator on an individual device is easy.

  - changing locators for a whole site is hard and must not be depended
    on (one time seems tolerable but is still undesirable).

  - if there is an identifier, independent of topological location, that
    is used for authentication, then it is probably in databases all
    over the place and changing it will be hard even for an individual
    device.

> same.  Touching everything *hurts*.

Certainly true for a whole site, because the problem is instantiation of
policy.  Changing addresses for individual devices is easy.

> namespace it is that causes this level of pain.

Which meaning of identifier are you using?

Scott (starting to catch up)