k administrators or vendors to manually enter information into routing tables. It works best when bandwidth and large amounts of network traffic are not issues. RIP, IGRP, EIGRP, and OSPF are all examples of dynamic routing protocols because they allow this process to occur. Without dynamic routing protocols, the Internet would be impossible. 11.8.9How routers use RIP to route data through a networkYou have a Class B network that is divided into eight subnetworks that are connected by three routers. Host A has data it wants to send to host Z. It passes the data down through the OSI model, from the application layer to the data link layer, where host A encapsulates the data with information provided by each layer. When the data reaches the network layer, source A uses its own IP address and the destination IP address of host Z, because that is where it wants to send the data. Then, host A passes the data to the data link layer.At the data link layer, source A places the destination MAC address of the router, to which it is connected, and its own MAC address in the MAC header. Source A does this because it sees subnetwork 8 as a separate network. It knows that it cannot send data directly to a different network, but must pass such data through a default gateway. In this example, the default gateway for source A is router 1. The data packet travels along subnetwork 1. All hosts that it passes by, examine it, but do not copy it, when they see that the destination MAC address carried by the MAC header does not match their own. The data packet continues along subnetwork 1 until it reaches router 1. Like the other devices on subnetwork 1, router 1 sees the data packet, and picks it up, because it recognizes that its own MAC address is the same as the destination MAC address.Router 1 strips off the MAC header of the data and passes the data up to the network layer where it looks at the destination IP address in the IP header. The router then s...
