WAS Topology: Front Ends

WAS Topology: Front Ends

WAS web server plug-in
Interface between a web server and an application server, determining server to which a client request, such as servlets, needs to be routed.

WebSphere DataPower
Secure appliance-based proxy server offering enhanced functionality, including WS-Addressing, custom advisors, QOS, and SLA.

WAS proxy server
Routes HTTP requests to content servers. Can be the initial point of entry for requests to servers in the enterprise. Not safe for DMZ deployment. Typically fronted by a web server, or used in internal only environments where stringent host security requirements are not required.

On Demand Router (ODR)
Intelligent router that is aware of the dynamic state of the cell. If one server in the cell fails, the requests are routed to another server. The configuration of the ODR in the DMZ is not supported.

DMZ Proxy Server for IBM WAS
Designed to be safely installed on a stand-alone node in a DMZ. Provides session affinity, failover support, and workload balancing for the WAS topology. The DMZ is a safe zone between firewalls, typically located between a client and a backend server. Accepts requests from clients on the Internet, and forwards the requests to servers in the enterprise environment.

Front end functionality

Functionality Web server plug-in used with either IHS or Apache Web server plug-in used with either IHS or Apache with Intelligent Management DataPower Service Gateway ODR DMZ Secure Proxy Server for IBM WAS -OR- WAS proxy server
Session affinity Yes Yes Yes^18, Yes^1,² 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
Route 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 WAS managed resources. However, some session management custom properties, such as HttpSessionCloneId, are not supported.

For generic server routing, where the resources are not WAS managed resources, active session affinity and passive session affinity need to be configured under generic server routing action.

WAS proxy servers and DMZ Secure Proxy Servers for IBM WAS 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 or an administrative agent. Configuration-only secure proxy profile can be managed through scripting or the administrative agent console. If we 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 WAS, and the core group bridge interface for the WAS 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 WAS, and the core group bridge interface for the WAS Network Deployment cells.

The web server plug-in statistics are obtained from request metrics.

WAS proxy server statistics and DMZ Secure Proxy Server for IBM WAS 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 WAS. The plug-in uses these tables for dynamic routing and failover scenarios within a cluster.

The proxy server uses the WAS 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 WAS 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 WAS 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 WAS configuration.

Content-based routing is provided via WebSphere DataPower configuration policy and stylesheets.

Functionality Web server plug-in used with either IHS or Apache Server with or without Intelligent Management DataPower Service Gateway ODR DMZ Secure Proxy Server for IBM WAS -OR- WAS 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:

WAS proxy servers support basic static file serving.

WAS proxy servers support HTML link rewriting.

This functionality only applies to Cryptographic Accelerators that WAS supports.
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.
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).

Related tasks
Proxy server setup
Configure a DMZ Secure Proxy Server for IBM WAS using the administrative console

Functionality	Web server plug-in used with either IHS or Apache	Web server plug-in used with either IHS or Apache with Intelligent Management	DataPower Service Gateway	ODR	DMZ Secure Proxy Server for IBM WAS -OR- WAS proxy server
Session affinity	Yes	Yes	Yes^18,	Yes^1,²	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
Route 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 WAS managed resources. However, some session management custom properties, such as HttpSessionCloneId, are not supported. For generic server routing, where the resources are not WAS managed resources, active session affinity and passive session affinity need to be configured under generic server routing action. WAS proxy servers and DMZ Secure Proxy Servers for IBM WAS 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 or an administrative agent. Configuration-only secure proxy profile can be managed through scripting or the administrative agent console. If we 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 WAS, and the core group bridge interface for the WAS 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 WAS, and the core group bridge interface for the WAS Network Deployment cells. The web server plug-in statistics are obtained from request metrics. WAS proxy server statistics and DMZ Secure Proxy Server for IBM WAS 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 WAS. The plug-in uses these tables for dynamic routing and failover scenarios within a cluster. The proxy server uses the WAS 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 WAS 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 WAS 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 WAS configuration. Content-based routing is provided via WebSphere DataPower configuration policy and stylesheets.

Functionality	Web server plug-in used with either IHS or Apache Server with or without Intelligent Management	DataPower Service Gateway	ODR	DMZ Secure Proxy Server for IBM WAS -OR- WAS 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: WAS proxy servers support basic static file serving. WAS proxy servers support HTML link rewriting. This functionality only applies to Cryptographic Accelerators that WAS supports. 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. 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).