Internet Protocol (IP) is a piece of software that operates at the Network Layer of the OSI Model. IP provides the following:
- Unique Addresses
- Connectionless Communication
- Routing
- Unicast, Broadcast and Multicast
UNIQUE ADDRESSES
Everything connected to the Internet must have a unique numerical address. Just like your house has a unique address, so does each computer attached to the Internet. These addresses are not fixed, and can be changed when necessary. These addresses are represented in what is called 'dotted-decimal notation' which means is that there are numbers with dots in between them that look like this: 204.25.183.4.
Always remember that computers use these dotted-decimal 'IP Addresses' to communicate and never use letters or names.
CONNECTIONLESS COMMUNICATION
IP communication is connectionless, and does not bother to set up dedicated end-to-end connections for communication. Upper layer protocols such as TCP are used for setting up connections and tearing them down, managing the recovery of lost data and other errors. These protocols function at the Transport layer of the OSI model or higher.
ROUTING
IP is aware when a computer's address is part of the local group of computers, or somewhere else. Routing is the part of IP that allows very intelligent and specialized routing devices (routers) to recognize that information is not part of the local group of machines, and needs to be forwarded to the destination. These devices are smart enough to 'figure out' how to get to destinations they aren't directly connected to. The process of forwarding the information is called routing. Routing is covered in detail in another section.