NonStop Server Guide for BEA WebLogic Server 8.1

Using the WS Plug-in
HP NonStop Server Guide for BEA WebLogic Server 8.1—529891-001
8-3
Requirements
useful when an application server is configured, for security reasons, to use
TCP/IP addresses that are not visible to external clients. Using passthrough mode
also has advantages in load balancing. Requests to stateless applications can be
routed to the least busy server on a per-request basis. Requests to session-based
applications are routed to the server in which the session was created. However, if
that server fails, the WS Plug-in can redirect the request to an alternative member
of the WebLogic Server cluster. Furthermore, if the application is configured for
session replication, the WebLogic Server replicates session state to a separate
server in the cluster. This means that the alternate server can restore the user’s
session state.
Requirements
iTP Secure WebServer requires HP NonStop™ SQL/MP. Therefore, to use the WS
Plug-in you must have NonStop SQL/MP installed and running on the same system (in
addition to HP NonStop™ SQL/MX required by the WebLogic Server). Use a D43
release version update (RVU) or later of NonStop SQL/MP.
Compatibility
The WS Plug-in is backward compatible; it supports all the functions provided by the
iTP Secure WebServer version of the RLS. For migration information, see Migration
Considerations.
Background
Web applications can include static and dynamic content. Static content includes
applets, HTML documents and image files. Web servers can support static content
more efficiently than Java-based web containers.
To process dynamic content, such as servlets and JavaServer Pages (JSP), you must
have a web container. Servlets and JSPs usually require access to database tables or
Enterprise Java Beans (EJB) applications. Therefore, requests with dynamic content
can require significantly more system resources than requests with static content
(which is simply transferred to the client). This contrast is the basis of the need for the
enhanced load balancing function in the WS Plug-in.
For example, you can use iTP Secure WebServer on a NonStop server in conjunction
with a WebLogic Server application server that has multiple target application server
processes. The iTP Secure WebServer services the static content and provides user
authentication (either Digital Certificate or HTTP-based). Requests for dynamic content
(which are not supported by iTP Secure WebServer) are sent to the WS Plug-in, which
forwards them to the appropriate target application server process in the WebLogic
Server cluster. The WS Plug-in selects the target application server process using the
following criteria:
•
If a WS Plug-in cookie is present, the request is associated with an existing
session and must be routed to a specific target application server process.