delivery of applications, you can integrate the NetScaler appliance with Citrix
XenApp and use the NetScaler load balancing feature to distribute the load
across the XenApp server farms. The following figure is a topology diagram of
such a setup.
Figure 1. Load
Balancing of XenApp
The Web Interface
servers provide secure access to XenApp application resources through the
user's Web browser. The Web Interface client presents to the users all the
resources, such as applications, content, and desktops that are made available
in the XenApp server farms. Users can access the published resources through a
standard Web browser or through the Citrix online plug-in.
The Web browser
on the user's device sends information to the Web server, which communicates
with the servers on the server farm to provide the user with access to the
The Web Interface
and the XML Broker are complementary services. The Web Interface provides users
with access to applications, and the XML Broker evaluates the user's
permissions to determine which applications appear in the Web Interface.
The XML service is
installed on all the servers in the server farm. The XML service specified in
the Web Interface functions as an XML broker. On the basis of the user
credentials passed by the Web Interface server, the XML Broker server sends a
list of applications accessible to the user.
enterprises where multiple Web Interface servers and XML Broker servers are
deployed, Citrix recommends load balancing these servers by using NetScaler.
Configure one virtual server to load balance all of the Web Interface servers
and another for all of the XML Broker servers. The load balancing method and
other features can be configured on the virtual server as required.
Note: Although you
can use the HTTP protocol, Citrix recommends that you use SSL for communication
between the client and the NetScaler. You can use the HTTP protocol for
communication between the NetScaler and the WI servers even though you use the
SSL protocol for communication with the client.
utility provides a wizard for setting up basic load balancing for XenApp.
wizard, you can configure Web Interface servers and a virtual server for them,
and XML Broker servers and a virtual server for them. You can also specify the
site through which the status of Web Interface servers can be monitored and the
software application used to monitor the status of the XML Broker servers.
When you complete
the wizard, a basic load balancing setup is configured on the NetScaler. The
specified virtual servers are created and bound to the services specified as
Web Interface services and XML Broker services. Each virtual server is
configured with the default load balancing method, and the default features are
enabled. A monitor is created and bound to each virtual server.
The wizard creates
a basic setup with default values for options such as the load balancing
method, policies, persistence, and advanced settings. You can change any of the
values if necessary.