ROUTING TABLE GENERATION

We all know that there was no automatic provisioning to generate a routing table for the nodes  in ns2. One of the way to solve this is by analyzing trace file generated by using some high level scripts like awk script, perl script or some other scripts.But it is little complex and also we have good knowledge in that and another way is to generating routing table is by modifying the existing routing protocol.

Here, we are going to generate routing tables for tcl scripts by modifying AODV protocol. For that we have to modify following files in the AODV directory[for AODV directory look at ns2.35 folder];

1. aodv.h 
2. aodv.cc

1. aodv.h modification

First display aodv.h file and then add the following lines inside the class AODV in the protected scope Add the line after the rt_down() function.

void rt_print(nsaddr_t nodeid);

Save the aodv.h file and

2. aodv.cc modification

Now click on aodv.cc file and select display option,

Now add the following function rt_print to the aodv.cc file probably below rt_down function.

void  AODV::rt_print(nsaddr_t nodeid) {

FILE *fp;

fp = fopen("route_table.txt", "a");

aodv_rt_entry *rt;

for (rt=rtable.head();rt; rt = rt->rt_link.le_next) {

fprintf(fp, "NODE: %i \t %f \t %i \t %i \n", nodeid, CURRENT_TIME, rt->rt_dst, rt->rt_nexthop);

}

fclose(fp);

}

This function records the routing table entry into the file route_table.txt

The above code ;

1. Creates a file pointer under append mode.
2. Creates a pointer to routing table entry.
3. Process the queue and finally print the values to the file with file pointer fp.
4. Close the file pointer.

Now finally we have to call the function that we written above,we can call it in any part of protocol. Here we are going to call inside recvReply() function.

For that we have to write following line inside if (ih->daddr() == index);

 rt_print(index);

After completing these steps.Open the terminal window and change the directory to the ns2.35 by using following command.

cd /home/user/Desktop/ns-allinone-2.35/ns-2.35 [change path as yours]

and now type 

                                                                     make clean 

then type

                                                                         make

then type

                                                               sudo make install

  

         

After successful completion of steps.Run a sample program.
For AODV,Click here
For sample program,click here  and run the program using command ns filename.tcl

Screen shot of a routing table

Note: File route_table.txt will be saved in the directory where program is located

This post is taken and modified from www.elmurod.net and www.nsnam.com