The next hop is among the series of routers that are connected together in a network and is the nextpossible destination for a data packet. When a packet destined for a remote network arrives at the router, the router matches the destination network to a route in the routing table. If a match is found, the router forwards the packet to the next hop address out of the identified interface. In computer networking, a hop is one portion of the path between source and destination.
More specifically, next hop is an IP address entry in a router’s routing table, which specifies the nextclosest/most optimal router in its routing path. Assume that either PC1 or PC2 has sent a packet destined for either the 10.1.1.0 or 10.1.2.0 network. When the packet arrives on the R1 Gigabit interface, R1 will compare the packet’s destination IPv4 address to entries in its routing table. Based on the content of its routing, R1 will forward the packet out of its Serial 0/0/0 interface to the next hop address 18.104.22.168.
Notice how directly connected networks with a route source of C and L have no next-hop address. This is because a router can forward packets directly to hosts on these networks using the designated interface.
It is also important to understand that packets cannot be forwarded by the router without a route for the destination network in the routing table. If a route representing the destination network is not in the routing table, the packet is dropped (that is, not forwarded). However, just as a host can use a default gateway to forward a packet to an unknown destination, a router can also include a default route to create a Gateway of Last Resort. The default route could be manually configured or dynamically obtained.