title: How to implement application layer behaviour in ns-2 using Tcl
body: <p>Clumsy title, apologies.</p>
  
  <p>I'm quite new to ns-2, well by that I mean I can create simulations fine as long as I don't need to do anything outside of the core functionality.</p>
  
  <p>I want to make a very simple SNMP model (as there is no SNMP model that I can find for ns-2), that is literally a case of 1 node polling all other nodes on a subnet, and the other nodes responding. This will happen every n seconds according to the polling rate.</p>
  
  <p>It's easy enough to set up a CBR UDP agent with an interval parameter to model the polling, but what is the best way to get the other nodes to respond upon receiving a packet? Or is this even the best way to do it?</p>
  
  <p>I ask this not in the spirit of expecting someone to plaster a massive C++ script here to help me, but because from what I can find by googling, it's hinted that this sort of thing should be quite straightforward using the Tcl interface.</p>
  
  <p>Does anyone have the faintest idea what I'm on about and if so any useful pointers?</p>
  
  <p>Thanks alot,
  Duncan</p>