Specifications

26 Chapter 1

Directory Service Concepts

•

Service Location Protocol (SLP), an open standard for discovering file and print

services

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Server Message Block (SMB), the protocol used by Microsoft Windows for file, print,

and other services

In fact, Open Directory can provide information about network services both from

service discovery protocols and from directory domains. To accomplish this, Open

Directory simply asks all its sources of information for the type of information

requested by a Mac OS X process. The sources that have the requested type of

information provide it to Open Directory, which collects all the provided information

and hands it over to the Mac OS X process that requested it.

For example, if Open Directory requests information about file servers, the file servers

on the network respond via service discovery protocols with their information. A

directory domain that contains relatively static information about some file servers also

responds to the request. Open Directory collects the information from the service

discovery protocols and the directory domains.

When Open Directory requests information about a user, service discovery protocols

don’t respond because they don’t have user information. (Theoretically, AppleTalk,

Rendezvous, SMB, and SLP could provide user information, but in practice they don’t

have any user information to provide.) The user information that Open Directory

collects comes from whatever sources have it—from directory domains.

File server