Routing tables are maintained either manually by a network administrator, or updated dynamically with a routing protocol.
Featured Success Stories. Finds its own IP address as the destination in the IP packet. Static vs. The router needs to create a frame to send the packet to the destination host.
There are three different methods for populating a routing table: directly connected subnets. Now, we are going to describe step by step what happens when Host A Network A wants to communicate with Host B Network B which is on a different network.
If not, drop the frame. R1 will do this and since this changes the IP header, we have to calculate a new header checksum. Dynamic routing uses special routing information protocols to automatically update the routing table with routes known by peer routers.
Host A is configured to send all packets destined for remote networks to router R1.
In general, most routing software determines a route through a shortest path algorithm. Interior gateway protocols are used to distribute routing information inside of an Autonomous System AS. First, the router looks in the ARP cache to determine whether the hardware address has already been resolved from a prior communication.
Within C, the routing module will know from the network number of each interface which one to use for forwarding IP packets.