IP address and network mask identify the destination network, the distance shows the number of routers between the transmitter and receiver, and the last column shows which router advertised this route. With the 'Time', the dynamic table shows how old the route is. The value in this column acts as a multiplier for the interval at which the RIP packets arrive, so a '1' stands for about 30 seconds, a '5' for about 2.5 minutes, and so on. When new information about a route arrives, this route is considered to be directly accessible and receives the time '1'. The value in this column is automatically incremented when the corresponding amount of time has elapsed. After 3.5 minutes, the distance is set to '16' (route unavailable), and after 5.5 minutes the route is deleted.
If the router now receives an IP RIP packet, it must decide whether or not to include the routes it contains in its dynamic table. This is done as follows:
- The route is included if it is not yet listed in the table (if there is enough space in the table).
- The route is present in the table with the time from '5' or '6'. The new route will be used if it has the same or a better distance.
- The route is present in the table with the time from '7' to '10', so it has the distance '16'. The new route will always be used.
- The route is present in the table. The new route comes from the same router that also communicated this route, but has a worse distance than the previous entry. If a device communicates the degradation of its own static routing table in this way (e.g. a disconnect increases the distance from 1 to 2, see below), the router accepts this and includes the poorer entry in its dynamic table.
