Brocade Virtual ADX Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 260)

244 Brocade Virtual ADX Server Load Balancing Guide
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Layer 7 content switching
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• Support for persisting requests to servers, along with simple forwarding actions
• Support for content-rewrite functions, including cookie and HTTP header insertion and deletion
To configure Layer 7 content switching, you define content switching rules and policies. A rule
specifies the content that the Brocade Virtual ADX looks for in the incoming traffic, and a policy
associates rules with one or more actions that specify how the Brocade Virtual ADX handles traffic
matching the rule.
The following sections explain how to configure Layer 7 content switching on a Brocade Virtual ADX
and how to display information about a Layer 7 content switching configuration.
Enabling CSW
To enable Layer 7 content switching, you bind a content switching policy to a virtual server. For
example, to enable Layer 7 content switching on a virtual server called cswVIP, enter commands
such as the following.
Virtual ADX(config)#server virtual-name-or-ip cswVIP 192.168.20.254
Virtual ADX(config-vs-cswVIP)#port http csw-policy p1
Virtual ADX(config-vs-cswVIP)#port http csw
Syntax: [no] port portnum csw-policy policy-name
Syntax: [no] port portnum csw
The policy-name variable is a Layer 7 content switching policy. Refer to “Creating a policy” on
page 250.
Specifying scan depth
To configure actions based on content carried on top of the HTTP protocol (for example, XML
content) you must specify how far into the packet the Brocade Virtual ADX scans for the content.
The Brocade Virtual ADX scans up to the specified limit. If you do not specify a scan depth, then the
Brocade Virtual ADX scans to the end of the packet.
To specify the scan depth for HTTP content, enter commands such as the following:
Virtual ADX(config)#server virtual-name-or-ip cswVIP 192.168.20.254
Virtual ADX(config-vs-cswVIP)#port http csw-scan-depth 128
Virtual ADX(config-vs-cswVIP)#port http csw
Syntax: [no] port portnum csw-scan-depth length
The length variable specifies the number of bytes the Brocade Virtual ADX scans for content in a
packet. You can specify up to 8192 bytes. By default, the Brocade Virtual ADX scans to the end of
the packet.
Enabling CSW load balance
In HTTP 1.1, a client can send multiple requests over the same connection. The current behavior is
that Brocade Virtual ADX regards all requests as independent requests, namely it uses the load
balance predictor to perform server selection for each request. This is true even where the next
request from the client's connection goes to the same server group. After server selection, this
request may go to a different real server within the same server group. This can introduce the extra
delay for the client because it needs to establish a new connection for the new real server. If the
next request from the same client connection is forwarded within the same server group, the