[ns] incoming queues???

[Kaleelazhicathu R R Kumar <iscp9133@nus.edu.sg>]

hi all,
   is there a concept of both incoming and outgoing queues in ns??as far as
i could see from the manual,the queues on the links simulate the output
buffers in a router ie, the outgoing queues...so considering a simple
topology as shown below:

                 L1                  L2
       n1-----------------n2------------------n3
                            |  
                            |
                            |   L3
                            |
                            n4

if traffic from nodes n1 and n4 gets aggregated at n2, how can i apply an
incoming queue at n2?? or is it that the queue at L2 act as the aggregating
queue??? hope that i made my question clear...i will appreciate your help in
this regard.
    thanks.
    Renjish...