WebSphere Application Server V7.0: Concepts ... - IBM Redbooks

User
Figure 5-8 illustrates a topology with redundancy of several components.
Outside World DMZ Internal Network
I
N
T
E
R
N
HTTP/HTTPS
E
T
Protocol Firewall
Load
Balancer
System A
Load
Balancer
System B
Proxy
Server
System C
Proxy
Server
Load
Balancer
System E
Load
Balancer
System D System F System H
Figure 5-8 Topology with redundancy of several components
Web
Server
Plug-in
System G
Web
Server
Plug-in
Cell Multiple
Servers
Application
Server 1
Application
Server 1
Server I
Application
Server 2
Application
Server 3
Server J
Application
Server 5
Application
Server 6
Server K
Application
Server 7
Application
Server 8
Server L
Cluster
Server M
Deployment
Manager
Directory
and Security
Services
Existing
applications
and dat a
The following components are redundant in this example:
► Two clusters of Load Balancers
In the illustrated topology there are two clusters of load balancers. Each of the
clusters provides a highly available cluster address. The first cluster, which
runs on System A with System B as hot standby, provides the cluster address
for the reverse proxies. This cluster address is used by the clients to access
the service.
The second cluster runs on System E, with System F as hot standby, provides
the cluster address for the Web servers, and is used by the proxy servers to
retrieve content if user requests cannot be served out of the cache. Refer to
“Horizontal scaling topology with an IP sprayer” on page 150 for a high level
overview how Load Balancers work.
Dom ain Firewall
Chapter 5. Topologies 161