IP forwarding also known as Internet routing is a process used to determine which path a packet or datagram

Datagram

A datagram is a basic transfer unit associated with a packet-switched network in which the delivery, arrival time, and order are not guaranteed....

 can be sent. The process uses routing information to make decisions and is designed to send a packet over multiple network

Computer network

A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....

s.

Ideally, algorithms

IP forwarding algorithm

The IP forwarding algorithm is related to the topic of routing and gives a more directed approach in forwarding datagrams over a network. In order to achieve a successful transfer of data the algorithm uses a routing table to select a next-hop router as the next destination for a datagram...

that are used for IP forwarding would take into account a packet/datagram's length, the type of service specified in the datagram's header, and the network load to determine the best path to send a packet to its intended destination. However, in general most routing software determines its route through a shortest path algorithm.