The "Simulator" object has member functions that do the following:
Create compound objects such as nodes and links (described later)
Connect network component objects created (ex. attach-agent)
Set network component parameters (mostly for compound objects)
Create connections between agents (ex. make connection between a "tcp" and "sink")
Specify NAM display options
Etc.
Most of member functions are for simulation setup (referred to as plumbing functions in the
Overview section) and scheduling, however some of them are for the NAM display. The
"Simulator" object member function implementations are located in the " ns-lib.tcl" file.
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$ns color fid color:
is to set color of the packets for a flow specified by the
.
This member function of "Simulator" object is for the NAM display, and has no effect on the
actual simulation. (设置标记颜色)
$ns namtrace-all file-descriptor:
This member function tells the simulator to record
simulation traces in NAM input format. It also gives the file name that the trace will be written to
later by the command $ns flush-trace. Similarly, the member function trace-all is for recording
the simulation trace in a general format.
proc finish {}:
is called after this simulation is over by the command $ns at 5.0 "finish". In this
function, post-simulation processes are specified.
set n0 [$ns node]:
The member function node creates a node. A node in NS is compound
object made of address and port classifiers (described in a later section). Users can create a node
by separately creating an address and a port classifier objects and connecting them together.
However, this member function of Simulator object makes the job easier. To see how a node is
created, look at the files: "ns-2/tcl/libs/ns-lib.tcl" and "ns-2/tcl/libs/ns-node.tcl".
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