user manual

Chapter 2: Borland Enterprise Server overview and architecture 11
BES services overview
the HTTP. protocol. The Apache web server is highly configurable and
extensible through the addition of third-party modules. Apache supports
clients with varying degrees of sophistication and supports content negotiation
to this end. Apache also provides unlimited URL ailing.
Borland has added an IIOP Plug-in to the Apache web server. The IIOP Plug-
in allows Apache and the Borland web container to communicate via Internet
Inter-ORB Protocol (IIOP), allowing users to add the power of CORBA with
their Web applications in new ways. In addition, IIOP is the protocol of the
VisiBroker ORB, allowing your Web applications to fully leverage the services
provided by the object-request-broker provided by Borland.
JMS
Borland Enterprise Server provides support for standard JMS pluggability, and
currently bundles the Tibco messaging service. Additionally, BES is certified to
support SonicMQ. Refer to Chapter 24, “JMS provider pluggability” for vendor-
specific information on JMS services.
Smart Agent
The Smart Agent is a distributed directory service provided by the VisiBroker
ORB used in BES. The Smart Agent provides facilities used by both client
programs and object implementations, and must be started on at least one
host within the local server network.
Note Users of the Web Edition do not have to use the Smart Agent if they expect
their Web server and Web containers to communicate through HTTP or
another Web protocol. To leverage the IIOP Plug-in (and, by extension, the
ORB provided with the Web Edition), however, the Smart Agent must be
turned on.
More than one Smart Agent can be configured to run on your network. When a
Smart Agent is started on more than one host, each Smart Agent will
recognize a subset of the objects available and communicate with the other
Smart Agents to locate objects it cannot find. In addition, if one of the Smart
Agent processes should terminate unexpectedly, all implementations
registered with that Smart Agent discover this event and they will automatically
re-register with another Smart Agent. It should be noted that If a heavy
services lookup load is necessary, it is advisable to use the Naming Service
(VisiNaming). VisiNaming provides persistent storage capability and cluster
load balancing whereas the Smart Agent only provides a simple round robin
on a per osagent basis.
For more information, go to the VisiBroker for Java Developer's Guide Using
the Smart Agent section.