8.2.1 The sample topology

Our sample topology on the Windows 2000/AIX platform demonstrates the following key features:

Use of WebSphere Edge components for caching and Web server load distribution.
Web container workload management with WebSphere clusters, both horizontally and vertically, for handling servlet requests.
EJB container workload management, both horizontally and vertically.

The topology includes...

A cluster of two Web servers hosts, cluster.itso.ibm.com, running the Load Balancer function, anticipated by a caching proxy, both from WebSphere Edge Components.
A dedicated Deployment Manager machine managing the WAS cell, running IBM WAS ND V6.
Within this cell, we have a WebSphere cluster with various appserver processes. IBM WAS ND V6 is installed on both machines.
A dedicated database server running IBM DB2 UDB V8.2.

While this chapter describes how to configure a split JVM topology with the Web containers and EJB containers running in separate appservers, this is done so only for informational and demonstration purposes.

A negative performance impact will likely result when an application is deployed in this fashion. Better performance, scalability and failover is achieved when the Web components for an application are deployed in the same appserver as the EJB components.

All machines are part of the same network. However, we choose different IP address ranges to distinguish between the DMZ network, the application network, and the back-end network. In a real production site, these networks would certainly be isolated with firewalls.


Name	Network	IP address	Subnet mask	Function
cproxy	DMZ Network	10.20.10.101	255.255.0.0	Caching Proxy
lb	DMZ Network	10.20.10.102	255.255.0.0	Load Balancer
http1	DMZ Network	10.20.10.103	255.255.0.0	Web Server 1
http2	DMZ Network	10.20.10.104	255.255.0.0	Web Server 2
dm	Application Network	10.20.20.100	255.255.0.0	Deployment Manager
app1	Application Network	10.20.20.103	255.255.0.0	Application servers system 1
app2	Application Network	10.20.20.104	255.255.0.0	Application servers system 2
db	Back-end Network	10.20.30.100	255.255.0.0	Database server

Properties of our Web server cluster...


Name	Network	IP address	Subnet mask	Function
cluster	DMZ Network	10.20.10.100	255.0.0.0	Web server cluster

These tables show only short names for host names. In our sample topology, all host names belong to the itso.ibm.com domain. So, for example, the dm machine is also known as dm.itso.ibm.com.