[ns] bidirectional elements

[Nimrod Mesika <nimrodme@bezeqint.net>]

Is it possible to create a node (or any other object) that receives all
traffic going through this node in BOTH directions? (and can tell
whether its going in one direction or the other).

I want to create an object that receives all TCP traffic passing through
a certain node in the network (in both directions). That object should
be able to drop packets, delay packets etc., and of course must handle
multiple flows with different source nodes and destinations.

I have been unable to find anything resembling this behaviour in ns as
it seems the simulator uses internally unidirectional links (except for
LANs and wireless object which I'm not interested in right now). The
Snoop module might be similar to what I'm looking for but it's WAY too
complicated and I don't even have a simple tcl example for snoop...

Can anyone point me to the right direction?

Thanks,
-- Nimrod.