4.1 Revision of IP addresses

In this session we’ll be looking at routing. But firstly, a quick reminder of some of the work you did with IP addresses in earlier sessions – as we will be working with IP addresses in this part. You examined the PT Anywhere gateway’s IP address, which you found to be 192.168.0.1. You also saw how all devices on this network started with 192.168.0 with the final part used to identify a specific device on that network. The network itself would be allocated the IP address 192.168.0.0, which means all the devices could have a final digit between 2 and 254.

This type of address is one commonly used for private networks, specifically small home networks. Most of the networks we are concerned with at the moment will use addresses similar to this. They will also usually use the subnet mask 255.255.255.0. Remember the subnet mask shows the portion of the IP address that identifies the network.

Later, when we look at larger networks you will be using other types of IP address and subnet mask, such as those used in the next activity. Sometimes the network part is smaller and the host part bigger, so subnet masks such as 255.255.0.0 are used.

In this part we will be looking at how data is sent across different networks – looking at the IP addresses of source and destination devices is useful to determine whether two devices are on the same local network or whether they are on different networks.