[lisp] Mapping system observations

[Damien Saucez <[e-mail]>]

Hello,

We finally had no time to briefly present a measurement
campaign we made on the mapping system.

The slides are on 
http://www.ietf.org/proceedings/84/slides/slides-84-lisp-8.pdf
and I invite you to comment.

As you certainly know, the mapping system has been migrated
to LISP-DDT with success on 3/14/2012. As the migration was
planed, we have decided to measure it! To do so, we used
vantage points around the world in different network types (EID
space, commercial Internet, research Internet...). These vantage
points have measured for a period of about one month the
mapping system. To do so, they have send a Map-Request
for all the EID prefixes with lig, and this every 15 minutes.
We expected to observe a big difference of delay and mappings
between ALT and DDT. However, the result we obtain is that
the change is not very significant. There is no particular loss
of map-Request/Map-Reply during the transition and the delay
is not significantly increased or reduced. However, we observe
a much more variable delay now with DDT than before where 
delays were very stable with time.

After these measurements, we looked at the long term trends in
the mapping system thanks to lispmon. The general trend is that
the number of mapping increases (and more particularly the
negative mappings) and that very few mappings use several
RLOCs. Looking at this.

This work is very brief and only show basic results, however, it
raises two interesting questions. First, how can we make the DDT
retrieval delay more stable (maybe it is just a question of
organisation and trafic). Second, can we imagine to simplify the
mappings such a way that all the complexity of mappings with
the priority, weight, R-bit... is there only when necessary?

I am looking forward for your comments,

Damien Saucez