You can select an intermediary to provide
session affinity, failover support, and workload balancing for your WebSphere® Application Server topology.
- TheWebSphere Application Server web server plug-in provides an interface between a web server
and an application server. The web server plug-in determines the server
to which a client request, such as servlets, needs to be routed.
- The WebSphere DataPower appliance is an advanced proxy
server that offers enhanced functionality, such as WS-Addressing,
custom advisors, QOS, and SLA.
You can also use the following stabilized components
as a reverse proxy between an HTTP client and a clustered application,
or a partitioned application.:
See the WebSphere DataPower Information Center at http://www.ibm.com/software/integration/datapower/library/documentation for more information about using WebSphere DataPower.
Use your web server of choice and the corresponding
web server plug-ins, unless you want to use the enhanced capabilities
of a WebSphere DataPower appliance, such as WS-Addressing, custom
advisors, QOS, and SLA.
The following tables compare the core application
server frontend functionality, and the non-core functionality of a
web server plug-in running in a modern web server, such as the IBM
HTTP Server, based on Apache HTTP Server (with and without Intelligent
Management), the on demand router, a WebSphere Application Server proxy server,
a DMZ Secure Proxy Server for IBM WebSphere Application Server, and a WebSphere
DataPower Service Gateway.
Table 1. Core functionality. Functionality |
Web server plug-in used with either
the IBM HTTP Server or the Apache Web Server |
Web server plug-in used with
either the IBM HTTP Server or the Apache Web Server with Intelligent
Management |
WebSphere DataPower Service
Gateway |
On Demand Router (ODR) |
DMZ Secure Proxy Server for IBM WebSphere Application Server -OR- WebSphere Application Server proxy server |
Session affinity |
Yes |
Yes |
Yes18, |
Yes1, 2 |
Yes (for DMZ proxy only) 1, 2 |
DMZ ready |
Yes |
Yes |
Yes |
No |
Yes (for DMZ proxy only) |
Custom advisors are supported |
No |
No |
Yes |
No |
No |
Service Level Agreement (SLA) |
No |
No |
Yes |
Yes |
No |
SIP proxy |
No |
No |
No |
Yes |
Yes |
ESI dynamic Caching |
Yes |
Yes |
No |
Yes 3 |
Yes 3 |
Managed from the administrative console |
Yes |
Yes |
Partial19 |
Yes |
Yes4 |
Stream caching (large response caching) |
Yes |
Yes |
No |
Yes |
Yes |
Dynamically receive management events5 |
No |
No |
Yes18 |
Yes6 |
Yes6 |
Multi cells routing |
No |
No |
Yes20 |
Yes8 |
Yes8 |
Performance monitoring |
Yes9 |
Yes9 |
Yes |
Yes10 |
Yes10 |
Load Balancing (weighted round-robin) |
Yes11 |
Yes11 |
Yes |
Yes11 |
Yes11 |
Routing rules are configurable |
No12 |
No12 |
Yes |
Yes |
Yes |
Interoperability with WLM |
Yes13 |
Yes13 |
Yes18 |
Yes |
Yes |
Web service affinity and failover (WS Addressing) |
No |
No |
Yes18 |
Yes |
Yes |
Rule expression and custom routing |
No |
Yes |
Yes21 |
Yes15 |
Yes15 |
Generic server cluster (GSC) affinity and failover |
No |
No |
Yes |
Yes16 |
Yes16 |
Per Request Trace |
No |
Yes |
Yes |
Yes |
No |
Weighted Least Outstanding Request (WLOR) |
No |
Yes |
Yes |
Yes |
No |
Health Policy Support |
No |
Yes |
Yes |
Yes |
No |
Table notes: - Session affinity is supported for WebSphere Application Server managed resources.
However, some session management custom properties, such as HttpSessionCloneId,
are not supported.
- For generic server routing, where the resources are not WebSphere Application Server managed resources,
active session affinity and passive session affinity need to be configured
under generic server routing action.
- WebSphere Application Server proxy
servers and DMZ Secure Proxy Servers for IBM WebSphere Application Server do not support
fragment caching. Only whole page caching, and the ESI invalidation
servlet are supported.
- Secure proxy profile on a DMZ installation can only be managed
using scripting or an administrative agent. Configuration-only secure
proxy profile can be managed through scripting or the administrative
agent console. If you use an administrative agent console, you must
register a proxy profile with the administrative agent.
- As performed by ODR in a WebSphere Extended Deployment environment.
- Static routing needs to be turned off and core group bridge tunneling
needs to be enabled for both the DMZ Secure Proxy Server for IBM WebSphere Application Server, and the core
group bridge interface for the WebSphere Application Server, Network Deployment cells.
- Requires core group bridge setup between the proxy cell and other
cells.
- Static routing needs to be turned off and core group bridge tunneling
needs to be enabled for both the DMZ Secure Proxy Server for IBM WebSphere Application Server, and the core
group bridge interface for the WebSphere Application Server, Network Deployment cells.
- The web server plug-in statistics are obtained from request metrics.
- WebSphere Application Server proxy
server statistics and DMZ Secure Proxy Server for IBM WebSphere Application Server statistics can
be retrieved from Tivoli performance viewer, ARM, and performance
mBeans.
- Random Load balancing is supported in addition to weighted round
robin.
- Web server plug-in can only do static routing.
- A web server plug-in indirectly has interoperability with WLM
through the exchange of dynamic workload manager (DWLM) Partition
Tables between the web server plug-in and WebSphere Application Server. The plug-in uses
these tables for dynamic routing and failover scenarios within a cluster.
- The proxy server uses the WebSphere Application Server WLM even if the
proxy server is running on a z/OS operating system.
- The DataPower appliance manager provides faster web service affinity
and failover service than Java proxy provides.
- Rule expression and custom routing allows administrators to override
default WebSphere Application Server routing
behavior. For example, you might not want requests forwarded to server1
in a cluster between 11:00 PM and 12:00 PM because you regularly apply
maintenance to that server during that time interval.
- Proxy server supports load balancing and failover for generic
server clusters with passive and/or active affinity.
- Requires WebSphere DataPower AO module.
- Configuration with regards to cluster members, weights, session
affinity, and application edition support is performed via the WebSphere
Application Server ISC Console, but it is retrieved and acted upon
by WebSphere DataPower.
- Multi cell routing is based on policy and rule configuration within
DataPower. This is independent of the WebSphere Application Server
configuration.
- Content-based routing is provided via WebSphere DataPower configuration
policy and stylesheets.
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Table 2. Functionality provided outside of the web server plug-in. Functionality |
Web server plug-in used with either
the IBM HTTP Server or the Apache Web Server with or without Intelligent
Management |
WebSphere DataPower Service
Gateway |
On Demand Router (ODR) |
DMZ Secure Proxy Server for IBM WebSphere Application Server -OR- WebSphere Application Server proxy server |
Common Gateway Interface (CGI) |
Yes |
No |
No |
No |
Request URI rewriting |
Yes |
Yes |
No |
No |
Efficient static file serving |
Yes |
No |
Basic1 |
Basic1 |
Compression |
Yes |
Yes |
Yes |
Yes |
Response filtering |
Yes |
Yes |
Yes2 |
Yes2 |
SSL termination |
Yes |
Yes |
Yes |
Yes |
Cryptographic Accelerator3 |
Yes |
Yes |
Yes4 |
Yes4 |
FIPS |
Yes |
Yes |
Yes |
Yes |
Third-party/customer-written plug-ins |
Yes |
Yes8 |
No |
No |
Logging |
Yes |
Yes |
Yes5 |
Yes5 |
Custom logging |
Yes |
Yes |
Yes |
No |
Disk caching |
Yes |
No |
Yes |
Yes |
Asynchronous request handling |
none or partial6 |
Yes |
Yes7 |
Yes7 |
Table notes: - WebSphere Application Server proxy
servers support basic static file serving.
- WebSphere Application Server proxy
servers support HTML link rewriting.
- This functionality only applies to Cryptographic Accelerators
that WebSphere Application Server supports.
See the Supported hardware and software web page .
- The support is provided by IBM JDK/JCE.
- Only NCSA common format is supported.
- The connection between a web server plug-in and an application
server is synchronous and consumes a thread while reading/writing
or waiting for data. See your web server documentation for information
about how your particular web server handles client connections.
- Proxy server is optimized to handle AJAX long polling requests
under large scale deployments.
- Sophisticated rules and custom processing can be achieved using
Extensible Stylesheet Language Transformations (XSLT).
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