No packet can be forwarded without a route. Whether the packet is originating in a host or being forwarded by an intermediary device, the device must have a route to identify where to forward the packet.
--> If the destination network is directly connected, the router forwards the packet to the destination host. --> If no route exists for the destination network and a default route is present, the packet is forwarded to the next-hop router. --> If the originating host has a default gateway configured, the packet for a remote network can be forwarded using that route.
First, routing is the process a router performs when making forwarding decisions for each packet arriving at the gateway interface. To forward a packet to a destination network, the router requires a route to that network. If a route to a destination network does not exist on the router, the packet will be forwarded to the default gateway. Now, the destination network can be a number of routers or hops away from the default gateway. If the router has an entry for the network in its routing table, it would only indicate the next-hop router to which the packet is to be forwarded to and not the exact route to the final router. To sum it up, the routing process uses a routing table to map the destination address to the next hop and then forwards the packet to the next-hop address.
First, routing is the process a router performs when making forwarding decisions for each packet arriving at the gateway interface. To forward a packet to a destination network, the router requires a route to that network. If a route to a destination network does not exist on the router, the packet will be forwarded to the default gateway. Now, the destination network can be a number of routers or hops away from the default gateway. If the router has an entry for the network in its routing table, it would only indicate the next-hop router to which the packet is to be forwarded to and not the exact route to the final router. To sum it up, the routing process uses a routing table to map the destination address to the next hop and then forwards the packet to the next-hop address.
Neighboring routers are polled to find the best path. The packet will be forwarded to a default route if one is present.
ip packet header
A router would then consult its tables to determine what the next router address should be, and the best route.
The TTL (Time To Live) value is a number associated with network routing packets. An information packet will only be forwarded to a certain number of routers before the packet is dropped (deleted). The TTL is a counter decreased by 1 when the packet is forwarded to another router. When the TTL reaches zero, it will not be forwarded to another router.
When you send a packet to a host in a remote network, the packet is first forwarded to the default gateway of your local network. From there, the gateway routes the packet through various intermediary routers across the internet, using the destination IP address to determine the best path. Ultimately, the packet arrives at the target host's network, where it is directed to the specific device intended to receive it.
A packet will not go around networks endlessly because it has a field in the header called the TTL field. This is a number that limits the number of hops or networks a packet will be forwarded to.
The field in the IP header used to ensure that a packet is forwarded through no more than N routers is the "Time to Live" (TTL) field. The TTL value is decremented by each router that forwards the packet, and if it reaches zero, the packet is discarded. This mechanism prevents packets from circulating indefinitely in the network due to routing errors. By setting the TTL to a specific value, a sender can effectively control the maximum number of hops a packet can take.
The router discards the packet.The router forwards the packet out the interface indicated by the default route entry.
through the Fa0/1 interface