Inside Macintosh: Networking With Open Transport / Part 1 - Open Transport Essentials

Chapter 13 - AppleTalk Addressing

About AppleTalk Addressing

Because AppleTalk assigns node IDs dynamically, a node's address on an AppleTalk network can change from time to time. The Name-Binding Protocol (NBP) provides a mapping of names (like those in the Chooser) to network addresses in such a way that if the node ID changes, you can continue to reliably identify your application. An endpoint's name is its NBP name, also sometimes called its entity name. You can access information about an endpoint's address through an NBP mapper provider, which you can also use to locate other endpoints on the network. Because AppleTalk supports dynamic name registration, NBP mapper providers can use the Open Transport name registration and deletion functions as well as the other mapper functions.

When you bind an AppleTalk endpoint, Open Transport associates the endpoint with an address, which can be in one of these formats:

• The DDP address supplies the network address of an endpoint.

• The NBP address supplies the user-friendly NBP name.

• The combined DDP-NBP address combines the endpoint's network address and its NBP name.

• The multinode address supplies the physical network address of a multinode endpoint.

The following several sections discuss each address format in more detail.