together describe the Network identifier as mentioned earlier. For example, destination 192.168.0.0 and netmask 255.255.255.0 can be written as 192.168.0.0/24. The Gateway column contains the same information as the Next hop, i.e. it points to the gateway through which the network can be reached. The Interface indicates what locally available interface is responsible for reaching the gateway. In this example, gateway 192.168.0.1 (the internet router) can be reached through the local network card with address 192.168.0.100. Finally, the Metric indicates the associated cost of using the indicated route. This is useful for determining the efficiency of a certain route from two points in a network. In this example, it is more efficient to communicate with the computer itself through the use of address 127.0.0.1 (called localhost) than it would be through 192.168.0.100 (the IP address of the local network card). Forwarding table Routing tables are generally not used directly for packet forwarding in modern router architectures; instead, they are used to generate the information for a simpler forwarding table. This forwarding table contains only the routes which are chosen by the routing algorithm as preferred routes for packet forwarding. It is often in a compressed or pre-compiled format that is optimized for hardware storage and lookup. This router architecture separates the control plane function of the routing table from the forwarding plane function of the forwarding table. This separation of control and forwarding provides uninterrupted high-performance forwarding. See also Luleå algorithm Internet protocol suite References External links IP Routing from the Linux Network Administrators Guide Internet architecture Routing Data structures