slp - Service Location Protocol
The Service Location Protocol (SLP) is a dynamic service
discovery protocol that runs on top of the Internet Protocol (IP).
The protocol is specified by the IETF standard-track documents RFC
2165, RFC 2608, RFC 2609; the API is
documented in RFC 2614. .
There are two components to the SLP technology. The first
is a daemon, slpd(8), which coordinates SLP operations. The
second is a software library, slp_api(3SLP), through which processes
access a public API. Both components are configured by means of the
SLP configuration file, slp.conf(5).
The SLP API is useful for two types of
Services and service information can be requested from
the API. Clients do not need to know the location of a required
service, only the type of service, and optionally, the service
characteristics. SLP will supply the location and other information to
the client through the API.
Programs that offer network services use the SLP
API to advertise their location as well as other service information.
The advertisement can optionally include attributes describing the service.
Advertisements are accompanied by a lifetime; when the lifetime expires, the
advertisement is flushed, unless it is refreshed prior to expiration.
API libraries are available for both the C and Java
SLP provides the following additional features:
- slpd(8) can be configured to function as a transparent directory
agent. This feature makes SLP scalable to the enterprise. System
administrators can configure directory agents to achieve a number of
different strategies for scalability.
- SLP service advertising and discovery is performed in scopes.
Unless otherwise configured, all discovery and all advertisements are in
the scope default. In the case of a larger network, scopes can be
used to group services and client systems so that users will only find
those services which are physically near them, belong to their department,
or satisfy the specified criteria. Administrators can configure these
scopes to achieve different service provider strategies.
- Services may be registered by proxy through a serialized registration
file. This is an alternative to registering services through the
API. See slpd.reg(5) for more information.
See attributes(7) for descriptions of the following
slp_api(3SLP), slp.conf(5), slpd.reg(5),
Guttman, E., Perkins, C., Veizades, J., and Day, M., RFC 2608,
Service Location Protocol, Version 2, The Internet Society, June
Guttman, E., Perkins, C., and Kempf, J., RFC 2609, Service
Templates and Service: Schemes, The Internet Society, June
Kempf, J. and Guttman, E., RFC 2614, An API for Service
Location, The Internet Society, June 1999.
Veizades, J., Guttman, E., Perkins, C., and Kaplan, S., RFC
2165, Service Location Protocol, Network Working Group, 1997.