[RRG] Moving the problem to the global mapping system

[Robin Whittle <rw@firstpr.com.au>]

In "Re: [RRG]", responding to Tony's message of 22 March:

  http://psg.com/lists/rrg/2008/msg00964.html

Michael Meisel wrote, in part:

> (1) Is the mapping function successful in preventing edge 
>     network reachability from being propagated into the
>     global routing system?
> 
> (2) If yes, does it do so without simply moving the problem 
>     to the global mapping system?
> 
> Note that proposals that both (a) put reachability information into the
> mapping system and (b) involve any sort of push model start to look a
> lot like BGP, and therefore are going to have a hard time answering
> "yes" to (2) convincingly.

I think a good proposal should provide a Yes answer for (1) and may
well provide Yes for (2), as Ivip does.

Ivip's mapping information is a single ETR address.  If that ETR
becomes unreachable, the end-user (or some system they nominate)
uses the global fast hybrid push-pull mapping distribution system to
change the mapping to point to another ETR.

If Ivip's mapping distribution system was as costly, slow and
generally problematic as BGP's way of communicating route changes
globally, then a Yes answer to 2 would indicate that nothing of
great value had been achieved.  (BGP has to do it this way, since
each router in the system needs to make its own decisions, which
depend on the decisions of other routers.)

However, Ivip's mapping distribution system is completely different
from how BGP works and is optimised to handle much greater flows of
information, faster and more reliably than BGP.

  http://tools.ietf.org/html/draft-whittle-ivip-db-fast-push-00

When trying to frame questions about something like the "mapping
function", as we get down to questions which provide meaningful
answers regarding important principles and implementation details, I
think the questions only tend to make sense if certain architectural
attributes can be assumed.

I find it hard to think of common questions which tell us anything
meaningful about the five current map-encap schemes - LISP-NERD,
LISP-ALT, APT, Ivip and TRRP.

My message a week ago:

   http://psg.com/lists/rrg/2008/msg01091.html
   Taxonomy: 25 questions

had several questions which teased out commonalities and differences
in the mapping systems of these proposals.

  - Robin             http://www.firstpr.com.au/ip/ivip/


--
to unsubscribe send a message to rrg-request@psg.com with the
word 'unsubscribe' in a single line as the message text body.
archive: <http://psg.com/lists/rrg/> & ftp://psg.com/pub/lists/rrg