Tag: Network Layer

Sometimes the network has problems and a router must find a way to route data around the problems. A common problem is that one of the outbound links fails. Perhaps someone tripped over a wire and unplugged a fiber optic cable. At this point, the router has a bunch of network numbers that it wants…

Now that we can move data across a single link, it’s time to figure out how to move it across the country or around the world. To send data from your computer to any of a billion destinations, the data needs to move across multiple hops and across multiple networks. When you travel from your…

In the previous section where we talked about Link layer addresses, we said that link addresses were assigned when the hardware was manufactured and stayed the same throughout the life of a computer. We cannot use link layer addresses to route packets across multiple networks because there is no relationship between a link layer address…

There is no place in the Internet that knows in advance the route your packets will take from your computer to a particular destination. Even the routers that participate in forwarding your packets across the Internet do not know the entire route your packet will take. They only know which link to send your packets…

Increasingly, computers are portable or mobile. We just pointed out how important it was for the IP layer to track large groups of computers using network numbers instead of tracking every single computer individually. But since these network numbers indicate a particular physical connection to the network, when we move a computer from one location…

If you know how to find the IP address on your laptop, you can do a little experiment and look at the different IP addresses you get at different locations. If you made a list of the different addresses you received at the different locations, you might find that many of the locations give out…

If you wanted to connect the network for a new organization to the Internet you would need to contact an Internet Service Provider and make a connection. Your ISP would give you a range of IP addresses (i.e., one or more network numbers) that you could allocate to the computers attached to your network. The…

The Internetworking Protocol layer extends our network from a single hop (Link layer) to a series of hops that result in packets quickly and efficiently being routed from your computer to a destination IP address and back to your computer. The IP layer is designed to react and route around network outages and maintain near-ideal…

core router: A router that is forwarding traffic within the core of the Internet. DHCP: Dynamic Host Configuration Protocol. DHCP is how a portable computer gets an IP address when it is moved to a new location. edge router: A router which provides a connection between a local network and the Internet. Equivalent to “gateway”.…

You can take this quiz online at http://www.net-intro.com/quiz/4.10 What is the goal of the Internetworking layer? a) Move packets across multiple hops from a source to destina- tion computer b) Move packets across a single physical connection c) Deal with web server failover d) Deal with encryption of sensitive data How many different physical links…