The TCP/IP Guide  9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)       9  Name Systems and TCP/IP Name Registration and Name Resolution            9  Name System Issues, Concepts and Techniques

Name System Overview and Motivation 1 2 Name Spaces and Name Architectures (Flat and Hierarchical)

While the difference between numeric addresses and symbolic names is very significant to the users of network devices, it's important to remember that both numbers and names really serve the same basic purpose: device identification. Even when we use a name system to make devices easier to access, the computers themselves will still normally need to use the underlying numeric identifier. In essence, then, every device will end up with (at least) two identifiers: a number and a name.

The fact that devices end up with multiple identifiers is what allows both people and their machines to use the method of identification they prefer. However, it means that there must be ways of managing the assignment of names to devices, and of converting between them. A name system therefore involves more than just slapping names on computers. It must be, in fact, a complete system that allows names to be used by the humans while numbers continue to be used by the devices.

At the highest level, I consider a name system's jobs as encompassing these three basic functions:

• Name Space: The name system defines a name space for the networking system upon which it runs. The name space, also sometimes called a name architecture, describes the rules for how names are structured and used. It also defines how the name of one device is related to the names of other devices in the system, and how to ensure that no invalid names are given that would cause problems with the system as a whole.
  
  
• Name Registration: To implement the name system, a name must be assigned to each device on the network. Like any addressing system, a name system cannot work properly unless every name on the system is unique; we need some way of managing how the names are assigned so the result is sensible. The process of linking specific names to particular devices is usually called name registration.
  
  
• Name Resolution: As I mentioned above, even though humans like symbolic names, computers usually have little use for them. It is necessary to define a mechanism by which a device's symbolic name can be translated into its numeric address. This process is usually called name resolution.

Name System Overview and Motivation 1 2 Name Spaces and Name Architectures (Flat and Hierarchical)