[ns] QoS management simulation with NS

["Mark Janssen" <M.P.C.Janssen@phys.uu.nl>]

I would like to simulate a Quality of Service management solution over NS.
What I would like to do is add several hosts which exchange messages
requesting for instance bandwidth.
So for instance a node should be able to send a request to another node
requesting 100 Mb/s and the receiving node should then use some logic to
determine whether this is possible. These messages would ideally be the
payload of a lower protocol (eg TCP)
After that one of the nodes should instruct a router to change for instance
it's queue settings.
After reading the docs of NS I get the impression that NS is mostly meant
for lower protocol layers without giving much attention to the application
layer (at least not in a TCL script). So I was wondering, can a simulation
as above be done in NS? And how should I implement such an infrastructure.
Any pointers/hints would be greatly appreciated,

Thanks,

Mark