The routing table specifies exactly where the router (i.e. to which other router or computer) sends the data for any given IP addresses or IP address ranges. This type of entry is called a "route" since it is used to describe the path that the data packet should take. This procedure is also known as "static routing" since these entries are made manually and remain unchanged until you edit or delete them. In contrast to this, there is also "dynamic routing". Here, the various routers independently exchange information about the routes and keep this information up to date. Dynamic routing protocols include RIP, OSPF, BGP or LISP. When dynamic routing protocols are enabled, the router respects the static routing entries as well as the dynamic routing information.
The static unicast routes for IPv4 and IPv6 are each configured in separate tables. Multicast routes are configured using IGMP/MLD, PIM, and the tables for static multicast routes.
With the help of the static IPv4 routing table you also inform the router about the length of the route so that, in conjunction RIP, the most effective path is used where multiple routes exist to the same destination. The default setting for the RIP distance to another router is 0, i.e. the router is directly accessible. All locally accessible devices, i.e. other routers in the same LAN or workstations that are connected via proxy ARP, are entered with the distance 0. Setting a higher RIP distance (up to 14) reduces the "quality" of a route. These "unfavorable" routes will only be used if no other route to the corresponding remote site is available.
