SLP Release Notes

What’s in this Version
SLP Features
Chapter 110
How SLP Works
Consider the example of a user wanting to use the Printer services on a
network.
The following events occur on the server side:
As the printer is initialized and is in the ready mode the printer’s URL is
registered with the SA server and the DA server. The URL can have an
IP address or the domain name. Services advertise themselves by
registering with a Directory Agent. They can include in the registration,
a list of all the key-words and attribute value pairs that describe their
service. The registrations include a lifetime after which the service
information is to be removed by the Directory Agent. This is done in
order to avoid cases, where service hardware breaks but the service
continues to be advertised forever.
Explicit deregistration can also remove service information as part of a
Service Agent’s orderly shutdown procedure. Finally, Service Agents may
register current attribute information periodically, allowing User Agents
to ascertain their status, load, temperature, or other dynamic
characteristics.
The following events occur on the client side:
The client can query for a printer service with particular attributes, such
as Postscript printer, including the scope information. The client then
connects to the printer with the chosen attribute values within the scope
defined and processes the print instruction.
Defining Scopes
Services are grouped together using ‘scopes’. These are strings, which
identify services that are administratively identified. A scope could
indicate a location, administrative grouping, and proximity in a network
topology or any other category. Service Agents and Directory Agents are
always assigned a scope string. A User Agent is normally assigned a
scope string, through which the User Agent will be able to discover that
particular grouping of services. This allows a network administrator to
‘provision’ service to users. If the User Agent is configured with no scope,
it will discover all available scopes and allow the client application to
issue requests for any service available on the network.