Network communications involve many complex operations, but these operations can be grouped into four major categories:
For computers to communicate on networks, each must have an address. Just as postal services are unable to deliver a package without an address, computers are unable to communicate without an address. Since computers use numbers for addresses, but humans have an easier time distinguishing names, computers use protocols to match the number address to a name.
Once a computer has an address and/or name, it can start communicating with other computers. Its first communication is to let other computers know what services it has to offer. Then it must find out what services are being offered by other computers on the network. This is accomplished by using one of several service advertising and location protocols.
Having discovered other computers' addresses and the services they offer, a computer can start moving packets between itself and other hosts. To communicate efficiently, though, computers must know the fastest way to move data from point A to point B. Computers determine the best route from computer to computer with routing protocols.
Finally, network communication depends upon maintaining data integrity. NetWare® servers must coordinate time and NDS® replicas to ensure data integrity on the network. Time servers coordinate their time with other servers and relay the correct network time to NetWare clients. NDS replication is similar to time synchronization in that servers must keep and share accurate information to maintain fault tolerance and distributed access to the database.