There is some confusion as to the exact layer in which RIP / OSPF works. It is generally taught that these works in the network layer.
However, in Netsim we interpret RIP & OSPF as applications that modify the route tables.
RIP runs over UDP 520 while OSPF has its own transport mechanism.
Routing is done in the IP layer(layer 3 of the router), whereas RIP/OSPF helps in table formation by running in the application layer.
NetSim's Event Trace can be used to understand the events related to the different layers. one would notice that events would be occurring the application layer followed by the network layer for OSPF. There would no transport layer events