Computer Networks Lab (CS652) - Assignment 2

Submitted 
by -    Abhishek Das
on -    14-Feb-2017
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Files:  
        1. README file
        2. DOS ova files from VirtualBox
        3. Source code of programs
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DOS Setup:  The VMs using just dostalk program are configured to use 
        PCnet-Fast III virtual network adapter and make use of PCNTPK packet 
        driver. Their setup is identical to the the setup used in first 
        assignment.

            The VM used to run the router program is configured with two 
        PCnet-Fast III virtual adapters each bridged with a different physical 
        adapter on the host machine. Here the original PCNTPK driver cannot be 
        used, since it is unable to detect more than one network interfaces in 
        DOS. This problem is solved by a DOS program 'fixpcnt.com', provided by
        VMWare. After copying this program in the same directory as the 
        'pcntpk.com' driver when it is executed, it creates a patched copy of 
        the driver named 'pcntpk2.com'. Now this copy can be used to load 
        multiple copies of the driver associating each copy with a different 
        network adapter.
            PROMT> PCNTPK2.COM INT=0X61 IOADDR=0
            PROMT> PCNTPK2.COM INT=0X62 IOADDR=1
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Program usage:  

router.exe: It is executed with no arguments. 
                PROMPT> router.exe

            There is an interactive prompt which reads one character; 
            if 'y' or 'Y' is pressed the program terminates otherwise the prompt
            is repeated.

talk.exe:   It expects two arguments. The first being the IIP address of that 
            host and second is the IIP address of the router interface in the 
            same network. The IIP addresses are two hexadecimal numbes in the 
            range from 00 upto FF (both inclusive), separated by a colon. 
                PROMPT> talk.exe 1:2 1:1

            After starting the program, destination IIP address is asked for. It
            is to be provided in the same format as above. At any point in the 
            conversation the destination IIP address can be changed by pressing
            the key combination 'Ctrl-D'. The rest works just as in the dostalk 
            version for assignement 1.

Both of the above programs relies on one (in case of router, two) file(s) 
containing list of IIP addresses with corresponding MAC addresses. Name of the 
files in the current DOS setup are 'iiplist1' for network 1 and 'iiplist2' for 
network 2.
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Routing: pending...