No matter which form of communication you’re using, if you wish to reach a specific contact, you have to know how to address them. Name, telephone number, postal address – they all help us to direct our information to the correct recipients. This is no different with network technology. The IP and MAC address help identify the recipients here.
In the OSI model, the unicast is on the network layer (layer 3) and is therefore a routing diagram. A header with the address data is added to the information that is to be sent, regardless of whether it is an e-mail, a file or a simple website request. For simple procedures, the address of the recipient in the network is located in the header. The packet will be sent in this direction.
However, communication does not always take place within a closed network only where the router can reach each end point directly. Unicasts can also be sent between different (sub-)nets. IP routing technology is relied upon for this. This ensures that every hub knows which path the data packet must take for it to reach the legitimate recipient. Routers (the network hubs) use routing tables for this. To create these, the OSPF and RIPv2 protocols are used in particular.
In contrast to the IPv4 addresses that have been used up to now, the new IPv6 has earmarked a special feature for unicast: specific address ranges are reserved for the various types of communication. Multicast addresses are located in a different address range to the unicast addresses. There is also differentiation between various types of unicast addresses, which are represented by a prefix at the start of the address.