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

User
Outsid e Wo rld DMZ Internal Network
I
N
T
E
HTTP/HTTPS
R
N
E
T
Protocol Firewall
Load
Balancer
System A
Load
Balancer
hot standby
Load
Balancer
System B
Web Server
Plug-in
Web Server
Plug-in
Figure 5-5 Simple IP sprayer horizontally scaled topology
System C
System D
Cluster
System E
Deployment
Manager
Directory
and Security
Services
The active Load Balancer hosts the highly available TCP/IP address, the cluster
address of your service and sprays requests to the Web servers. At the same
time, the Load Balancer keeps track of the Web servers health and routes
requests around Web servers that are not available. To avoid having the Load
Balancer be a single point of failure, the Load Balancer is set up in a hot-standby
cluster. The primary Load Balancer communicates its state and routing table to
the secondary Load Balancer. The secondary Load Balancer monitors the
Domain Firewall
Application
Server
Application
Server
Existing
applications
and data
Note: To reduce the number of systems, and to demonstrate the co-location
capabilities of the Edge components Load Balancer, in Figure 5-5 the Load
Balancer and the Web server are installed on the same system. The Web
servers can be installed on separate systems in the DMZ as well. Consult the
Edge Components, Version 7.0 Information Center for supported network
configuration. See the following Web page:
http://publib.boulder.ibm.com/infocenter/wasinfo/v7r0/topic/com.ibm.
websphere.edge.doc/welcome.html
Chapter 5. Topologies 151