[Ns-developers] Cooperative ns-3 simulation with third party software via JSON-RPC

[Mathieu Lacage]

hi,

On Fri, 2009-01-09 at 18:09 +0100, Sébastien Vincent wrote:

> Last summer at the University of Strasbourg, we began a new extension 
> for ns-3 which allows external applications to
> interact with ns-3. Initially those functionalities were needed to 
> interconnect a mobility simulator with ns-3. The
> goal is that a mobility simulator do all mobility stuff while ns-3 
> realizes network (L2, L3, transport and application)
> stuff.

I have to confess that I am a bit curious: since you seem to have
implemented your own mobility simulator from scratch, why did you not
just add new mobility models to ns-3 rather than create a separate
project and deal with the communication between the 2 ? Are you re-using
the mobility simulator with another network simulator ? I am merely
curious :)

> We decided that this ns-3 extension should be as generic as possible and 
> that any external applications could "connect" to ns-3 via
> the network. So we decided to use JSON format [1] and its remote 
> procedure call version JSON-RPC [2]. We chose JSON

I am also curious about this: since ns-3 has a python binding, it should
be fairly trivial to use XML-RPC to remotely instanciate and control a
network topology simulation. Was it impossible to use XML-RPC from your
C++ application ?

> because it is more lightweight compared to XML (which is a very verbose 

Or maybe this is because you were worried about the XML part in XML-RPC.

[snip lots of interesting API and implementation details]

> To conclude we would like to know if this kind of features is 
> interesting to the community. If so, we have several questions we

I am not sure a lot of people would find these new features useful but I
don't see why we could not merge your code if it does not have a
negative impact on the existing codebase and if you maintain it.

> would like to discuss with you regarding the implementation of node 
> mobility in ns-3. We would be glad to discuss and improve our
> design solution.

If you have comments on the ns-3 mobility support, they are more than
welcome, regardless of whether you want or can merge your own code in
ns-3.

Anyway, this looks pretty cool and interesting so, thanks for releasing
all this code and taking time to let us know about it.

regards,
Mathieu