[ns] About the packet type

[Jianyu Dong <dongj@ee.eng.ohio-state.edu>]

HI, friends:
	I found Video and Audio packet types are defined
in the NS2. However, what 's it the packet format? Where
can I find the exact format of the defined packets?
	I want to use twp RTP sessions to transmit video
and audio at the same time. How can I attach Video and audio
packet to RTP session? I also find if I use the following 
program, I can't control the size of packet. The packet
size is always 210 byte. Does this mean the size of RTP 
packet is fixed? However, the size of RTP packet should not 
be fixed according to the protocol. Could you tell me
how to control the size of packet?
 
set src1 [new Agent/RTP]
set sink1 [new Agent/LossMonitor]
$ns attach-agent  $n0 $src1
$ns attach-agent $n1 $sink1

set ss1 [new Application/Traffic/CBR]
$ss1 set packetSize_ 100
$ss1 set rate_ 100kb
$ss1 attach-agent $src1
$ns connect $src1 $sink1
	Thank you very much!

Jianyu