[ns] NS - Multicast

[Chirdeep Chhabra <Chirdeep.Chhabra@dimail.epfl.ch>]

Hi all,
I need to simulate a multicast in NS. I have been trying to look into
some examples in /tcl/ ex
I tried to run srm-demo.tcl after making the changes of using dst_addr_
and dst_port_  instead of dst_.
I get an error which is below.

ns: reset-rcvr: can't unset "ack_": no such variable
    (Object unset line 1)
    invoked from within
"$rcvr($k) unset ack_"
    (procedure "reset-rcvr" line 4)
    invoked from within
"reset-rcvr"


Could someone tell me how I can change the reset-rcvr to avoid this
error. please let me know what is wrong.
thanks a lot
-chirdeep