The objective of this assignment is the simulation of the routing process in a router. You may use Java, C, C++ or Python as the language for building your program.

Download the associated text file RoutingTable.txt and RandomPackets.txt (given next to the Assignment link).

Exercise: You will write a program to simulate the routing decision taken at a router that we discussed in the lectures. You are given a text file (RoutingTable.txt) containing a routing table for a router (the five column generic routing table with mask, destination address, next hop, flag and interface).  You will notice that this is almost the same routing table as the one that we discussed in the lectures. The first few lines of the text file are shown below:

192.168.1.0/24  à Destination address/Number of ones in the mask

-               à - means no next hop E0              à Outgoing interface

192.168.2.0/24  à Destination address/Number of ones in the mask

192.168.4.2     à Next hop

S0              à Outgoing interface

Etc.

Notice that three rows are sufficient to capture the information in the five columns of the routing table. The type of entry (direct, network specific, host specific or default) is not given but you can determine that from the given information.

You are given another text file (RandomPackets.txt) that contains a list of packets with random destination addresses that arrive at this router. The first few lines of the text file are shown below:

192.168.1.1

192.168.3.2

200.56.45.89

255.0.0.0

127.0.0.1

etc.

If you check the above packets with the given routing table, you will notice that packet #2 is a host specific packet, packet #3 should take the default route, packet #4 does not belong to class A, B or C and should be discarded, packet #5 has a loopback address and should be discarded.

Your program should read the two text files and decide what to do with each packet, displayed as follows:

192.168.1.1 will be forwarded on the directly connected network on

interface E0.

192.168.3.2 will be forwarded to 192.168.5.2 out on interface S1

200.56.45.89 will be forwarded to 192.168.4.2 out on interface S0

255.0.0.0 is malformed; discarded

127.0.0.1 is loopback; discarded