Real packet in NS (next)

[Nguyen Tuan Hung <Nguyen.Tuan.Hung@eth.ericsson.se>]

Hi,
    In ns Node and Documentation, Part VIII Emulation is writen "Tag
egents embed live network data into simulates packet and vice-versa".
   Questions:
    1. How do I know to connect Simulator agent with Tap agent, example
udpTap [new Agent/TAP] and udpAgent [new Agent/UDP] ?
    2. If I attach udpCBR [new Application/Traffic/CBR] with udpAgent.
It really generate UDP packet?
    3. How look a simulator's IP packet in bytes?

Thanks
Hung