Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 23)

Brocade Virtual ADX Server Load Balancing Guide 7
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Chapter
2
Server Load Balancing
Overview
The Brocade Virtual ADX Application Delivery Switch (Brocade Virtual ADX) helps ease the
administration of TCP-based or UDP-based applications. They provide server load balancing (SLB)
for the application servers, help offload CPU-intensive tasks from the application servers, and
provide added security to the server farm.
In Figure 1 , the system administrator has greater flexibility in managing application server
resources. By using a Brocade Virtual ADX, the system administrator can seamlessly add or remove
the application servers (real servers) and handle the changing traffic requirements without
disrupting service to the end-users. The application clients access the virtual IP address or VIP
(virtual server) that is hosted by the Brocade Virtual ADX.
In addition to offering increased control over server resources, the Brocade Virtual ADX offers
numerous other functions, such as application health checks, server offload, and greater security.
FIGURE 1 Single virtual IP address mapped to multiple real servers
The server load balancing (SLB) requires associations between the application servers (real
servers) and the virtual server (VIP). The associations are done by binding TCP or UDP ports on the
real servers with TCP or UDP ports on the virtual server. When a client sends a TCP or UDP request
to an application port defined under the virtual server, the Brocade Virtual ADX identifies one of the
back-end application servers based on the configured load balancing method and forwards the
client request to it. The client is completely unaware of this traffic distribution, but observes
increased availability, faster response time and better throughput. The Brocade Virtual ADX can be
configured to host multiple application services such as web (HTTP), FTP, or DNS under a single
virtual server.