Introduction (1.0.1.1)
Networks allow people to communicate, collaborate, and interact in many ways. Networks are used to access web pages, talk using IP telephones, participate in video conferences, compete in interactive gaming, shop using the Internet, complete online coursework, and more.
At the core of the network is the router. A router connects one network to another network. The router is responsible for the delivery of packets across different networks. The destination of the IP packet might be a web server in another country or an email server on the local-area network.
The router uses its routing table to determine the best path to use to forward a packet. It is the responsibility of the routers to deliver those packets in a timely manner. The effectiveness of internetwork communications depends, to a large degree, on the ability of routers to forward packets in the most efficient way possible.
When a host sends a packet to a device on a different IP network, the packet is forwarded to the default gateway because a host device cannot communicate directly with devices outside of the local network. The default gateway is the destination that routes traffic from the local network to devices on remote networks. It is often used to connect a local network to the Internet.
This chapter will also answer the question, “What does a router do with a packet received from one network and destined for another network?” Details of the routing table will be examined, including connected, static, and dynamic routes.
Because the router can route packets between networks, devices on different networks can communicate. This chapter will introduce the router, its role in the networks, its main hardware and software components, and the routing process.
Class Activity 1.0.1.2: Do We Really Need a Map?
This modeling activity asks you to research travel directions from source to destination. Its purpose is to compare those types of directions to network routing directions.
Scenario
Using the Internet and Google Maps, located at http://maps.google.com, find a route between the capital city of your country and some other distant town or between two places within your own city. Pay close attention to the driving or walking directions Google Maps suggests.
Notice that in many cases, Google Maps suggests more than one route between the two locations you chose. It also allows you to put additional constraints on the route, such as avoiding highways or tolls.
Copy at least two route instructions supplied by Google Maps for this activity. Place your copies into a word processing document and save it for use with the next step.
Open the .pdf accompanying this modeling activity and complete it with a fellow student. Discuss the reflection questions listed on the .pdf and record your answers.
Be prepared to present your answers to the class.