Portlets available from local sources provide most of a portal's base functions. Remote portlets allow administrators to provide content without installation effort and without code running locally on the consuming portal server.
Portal Server implements the Web Services for Remote Portlets (WSRP) 1.0 standard, a web services protocol for aggregating content and interactive web applications from remote sources. The implementation includes the following:
The WSRP consumer, a web service client (the portal)
Invokes producer-offered WSRP web services
Provides an environment for end users to interact with portlets that one or more WSRP producers offer
The WSRP producer, a web server
Offers just one portlet or provides a runtime (or a container) for deploying and managing several portlets
Implements various WSRP interfaces and operations
Portal Server's implementation of the WSRP producer supports publishing JSR 168 portlets for use by remote WSRP consumers. The JSR 168 portlets are deployed locally on a portal server. An instance of the WSRP producer can publish these portlets.
Before a portal that acts as a WSRP consumer can access a remote portlet, the portal must find the producer's web service definition language (WSDL). The producer can register the WSDL, as well as other information related to the producer, in the UDDI (universal description discovery interface) service registry. Registration makes the portlet available to the consumer.
For additional information, see the WSRP 1.0 standard set by the Organization for the Advancement of Structured Information Standards (OASIS):
http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=wsrp