[ns] still can't simulate IVS

[Hanus Joel <jhanus@student.fsa.ucl.ac.be>]

Hello dear NS users,

I'd like to simulate IVS, but don't know if I must use IVS with other agents.

SO, if you have old scripts with IVS (even for ns-1), you can send them to me
or show me a guideline.
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HANUS Joel, ELEC23