[ns] buffer size reaches to thousands of packets!

[le hang]

Hi all!
anybody has a problem similar to me? i used queue monitor agent to get
number of packets which are available in buffer, the result i got is the
number of packets reached to thousands, and sometime it droped to negative
number, where is error, somebody told me that interactivity of modules in NS
has a problem, it's true? currently,i use NS-2.31, i have had no any problem
before. would somebody please to help me?
thanks in advance!
Hang
-- 
khicon
the FET of HUT