1. http://nile.wpi.edu/NS/ Jae Chung and Mark Claypool
NS2 by example
Jae Chung and Mark Claypool

2. OTcl Linkage adding a new basic network object an example
working around making OTcl linkage from C++ code
an example
creating a simple and dull agent called "MyAgent“
no behavior of an agent (i.e. no packet creation and transmission)

3. Export C++ class to OTcl
MyAgent
C++ Network Component
Derived from Agent
OTCL的物件
Linkage object between C++ and OTCL
OTCL
Agent/MyAgentOtcl
The Linkage Objec

4. 啟動時就會產生負責建立C++的object, 只會有一個
How it works
NS started
 executes static variable "class_my_agent"
the "Agent/MyAgentOtcl" class and its appropriate methods (member functions) are created in OTcl space )
create an instance in OTcl space by "new Agent/MyAgentOtcl"
"MyAgentClass::create" that creates an instance of "MyAgent" and returns the address.
啟動時就會產生負責建立C++的object, 只會有一個

5. Export C++ class variables to OTcl
configure (or change) variables in C++ from OTcl using the input simulation script.
binding functions are placed in the "MyAgent" constructor function
- bind(): real or integer variables - bind_time(): time variable - bind_bw(): bandwidth variable - bind_bool(): boolean variable

6. Export C++ Object Control Commands to OTcl
defining a "command" member function of your C++ object ("MyAgent")

7. Execute an OTcl command from C++.
Example: to print message in OTcl space
Get the address of “Tcl::instance()”
Then you can use function in OTcl

8. Compile and Run
Download "ex-linkage.cc" file, and save it under the "ns-2/common" directory.
Open "Makefile", add “common/ex-linkage.o" at the end of object file list (OBJ_CC = ).
Re-compile NS using the "make" command.
Download the "ex-linkage.tcl" file that contains "MyAgent" testing OTcl commands. (see Figure 22 for the input script and the result)
Run the OTcl script using command "ns ex-linkage.tcl".

9. Example
argc = 2, argv[0], argv[1]

10. Add New Queue Objective priority 15 to Q1 Others to Q2
Total queue size (Q1+Q2) <=PQ
Serve Q1 and Q2 in turn

11. Constructor
物件建立時會執行

13. Compile and Run
Download “dtrr-queue.h“ & “dtrr-queue.cc” files, and save it under the "ns-2/queue" directory.
Open "Makefile", add “queue/dtrr-queue.o" at the end of object file list (OBJ_CC = ).
Re-compile NS using the "make" command.
Download and run the "ex-dtrr-queue1.tcl” file

14. ex-dtrr-queue1.tcl 修改成根據flow id (fid)來判斷
Fid=1 to queue 1, high priority
Otherwise, to queue 2, low priority
Observe that no loss at CBR flow if it is set to fid=1.