Subject: Re: draft-ietf-ipngwg-site-prefixes (Fwd)

From: Erik Nordmark <[email-masked]>
Date: Thu, 9 Dec 1999 22:55:15 -0800 (PST)

Robert accidentally left off the ipng list.

>----------------Begin Forwarded Message----------------<

Date: Fri, 10 Dec 1999 15:14:29 +1100
From: "Robert Elz" <[email-masked]>
Subject: Re: draft-ietf-ipngwg-site-prefixes 
To: "Erik Nordmark" <[email-masked]>

    Date:        Thu, 9 Dec 1999 18:50:51 -0800 (PST)
    From:        Erik Nordmark <[email-masked]>
    Message-ID:  <Roam.SIMC.2.0.6.944794251.247.nordmark@jurassic>

  | You seem to be saying that this might not be the case - that the internal
  | view of the site (the scope over which a site-local applies) might be
larger
  | than the external view of the site (the global prefixes assigned to the
site).
  | Is this the case?

Yes.

Or smaller, or just not related in any way that you can rationally discern
from looking at global addresses assigned.

  | As an aside, one can avoid the introduction of "external view" and
"internal 
  | view" of a "site" by instead stating that the site is where a site-local 
  | address is unique and routable,

Sure.

  | but that various parts of the site use different global prefixes

Yes.

  | I'd prefer using that terminology to avoid introducing
  | different views of a "site".

Fine.

  | The only issue is the total size of the advertisement.
  | If there will be 15 site prefixes and 3 subnet prefixes each router
  | advertisement would have 15*64=832 bytes of prefix options.
  | But if there are 100 site prefixes each logical router advertisement would
be 
  | split over 6 packets each carrying a subset of the prefix options. This
  | seems obsessive.

And if, regardless of the number of global prefixes, the only way to
specify what is the site is to enumerate the prefix of every subnet in the
site?  (maybe 10's of thousands of them)   (And then aggregate where that
works, making note of there not being any kind of hole punching mechanism,
so you cannot say "all but")

kre
>----------------End Forwarded Message----------------<

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---

From: Erik Nordmark <[email-masked]>
Date: Thu, 9 Dec 1999 22:55:46 -0800 (PST)

>----------------Begin Forwarded Message----------------<

Date: Thu, 9 Dec 1999 22:32:41 -0800 (PST)
From: "Erik Nordmark" <[email-masked]>
Subject: Re: draft-ietf-ipngwg-site-prefixes 
To: "Robert Elz" <[email-masked]>
Cc: "Erik Nordmark" <[email-masked]>

> so you cannot say "all but")

Do you have a case where this might actually be useful?

While solving that problem might be interesting I don't have any information
to tell me that it would be relevant.
In practise I expect a site to be representable to the outside world
using aggregatable routes. This same aggregation can be used internally
when advertising the site prefixes.

  Erik

---

From: Erik Nordmark <[email-masked]>
Date: Thu, 9 Dec 1999 22:56:08 -0800 (PST)

>----------------Begin Forwarded Message----------------<

Date: Fri, 10 Dec 1999 17:47:22 +1100
From: "Robert Elz" <[email-masked]>
Subject: Re: draft-ietf-ipngwg-site-prefixes 
To: "Erik Nordmark" <[email-masked]>

    Date:        Thu, 9 Dec 1999 22:32:41 -0800 (PST)
    From:        Erik Nordmark <[email-masked]>
    Message-ID:  <Roam.SIMC.2.0.6.944807561.8220.nordmark@jurassic>

  | Do you have a case where this might actually be useful?

Not immediately, but since I have no idea how site addressing might end
up being useful, I don't want anything to restrict it.

  | In practise I expect a site to be representable to the outside world
  | using aggregatable routes.

I expect "objects" (not sites any more, as you defined site in a particular
way) to be representable that way.

  | This same aggregation can be used internally
  | when advertising the site prefixes.

Only if there is some kind of correspondence between the external
connectivity (giving the global addresing) and the internal notion
of the site.   I don't know that there will necessarily be any such
thing (though I wouldn't be surprised if it was often the case), and
don't want to start defining things now which depend upon that.

kre

ps: if I didn't send my previous message to the list, that was not
intentional.  I don't have a copy, so if I left out the cc header, and
you feel inclined, please forward it - your Reply-To header kills
me every time, my mailer will generally send only to addresses in a
Reply-To when such a header exists.