[ns] where is the definition of "Node alloaddr"

[HEI Xiaojun <heixj@ee.ust.hk>]

Dear ns users

In the multicast example ~/ns-2/tcl/ex/mcast.tcl, there is the following
command:

set group [Node allocaddr]

Would you please help me find the definition of "Node allocaddr" in the
ns source codes?

thanks for your help.

yours
sean