Subject: Re: [lisp] Fwd: Anybody can participate in the IETF (Was: Why is IPv6 broken?)

From: [email-masked] (Noel Chiappa)
Date: Mon, 18 Jul 2011 21:28:37 -0400 (EDT)

> From: Jeff Wheeler <[email-masked]>

    >>  Why will multi-homing of more sites on the network increase the number
    >>  of distant sites (whether those sites are multi-homed or not) which the
    >>  _average_ site communicates with?

    > Note that I am asking about _sites_, not routing entries, mapping
    > entries, or any other low-level mechanistic things. Once we're straight
    > there, we'll work on into lower-level issues like state, etc.

    > Today you may perceive a "site" as an entry in the BGP DFZ, which may
    > encompass several tens of thousands of end-users.

Ah, no. I _definitely_ do not perceive a 'site' as anything to do with
routing table entries, etc. To me a 'site' is an organization - a company, a
university, whatever.

How _those_ translate into routing table entries, etc, (both at the moment,
and going forward in time - and also into other mechanisms such as mappings)
is of course a necessary (but later) stage in any analysis - but I want to be
methodical, and start with the first step first.

So let's try it this way:

  Why will multi-homing of more organizations on the network increase the
  number of distant organizations (whether those are multi-homed or not)
  which the _average_ organization communicates with?

Note that there have historically been developments (e.g. the increase in
embedded content on web pages) which _have_ had an effect on "the number of
distant organizations ... which the _average_ organization communicates
with", so it's not like that _cannot_ change. What I'm after though, is
whether _multihoming_ will change it.

    > When a "site" becomes a SOHO network, a cell tower, a public wireless
    > hot-spot, etc. the average number of end-users per "site" decreases

At least two of those (the cell tower and wireless hot-spot) would be named
out of what I think of as RLOC space, and would not influence calculations on
the number of mappings, etc at all.

    > what it boils down to is the number of units of routing state will
    > increase to serve the same number of end-users.

It depends on what you mean by 'routing state'. Do you mean 'forwarding table
entries' - or to be more precise, 'things nameable in a forwarding table
entry', or 'elements in the global path selection process' (aka 'routes')? At
the moment they are the same, but since LISP is trying to break that
association, it's necessary to think of them separately.

Anyway, if you meant 'elements in the global path selection process' I would
definitely disagree.

	Noel