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3 Using Verkkoke as Student

As mentioned in Introduction, Verkkoke 1.1 is designed for use in conjunction with a programming assignment.

To do the programming assignment, the student takes the following steps:

  1. The student logs in to the Learning Management System (LMS) to read assignment instructions, to commence the assignment and retrieve assignment results.
  2. Externally, the student makes the client program, then logs back into the LMS to start the assignment.
  3. The system generates a random topology for the student.
  4. The student has the client program contact the simulation server. The simulation server sends routing messages to the client based on the topology generated for the student.
  5. The client builds its routing table based on the routing messages and sends that routing table to the server. The simulation server checks whether the routing table is correct and stores the result in the LMS. The student goes back to step 1, to see the result. If the routing table is not correct, the student is allowed to submit again.
steps.png

Step 3 in the above process description can be reached in two different modes, practice mode and submission mode. When in practice mode, the student can choose the size of the generated topology. A picture of the topology is shown when it has been generated. The student has the option to generate a new topology, if desired. When in submission mode, the system will always generate a new topology of certain, teacher configurable number of nodes, and the topology is not shown to the student.

The student's client builds its routing table based on routing messages sent by the server. The format and content of these messages depend on the simulated routing protocol. Verkkoke 1.1 simulates two routing protocols which are abstractions of real routing protocols. The abstractions are called DV (which stands for Distance Vector) and LS (which stands for Link State), and they are loosely based on the real protocols RIP and OSPF, respectively.

The student's client sends its routing table to the server using a separate submission protocol which uses TCP. The server then compares the submitted routing table with the routing table of the student's node in the simulation.