Brocade Virtual ADX OpenScript Programmer’s Guide (Supporting ADX v03.1.00) - Manual (Page 9)

Brocade Virtual ADX OpenScript Programmer’s Guide 1
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Chapter
1
Overview of OpenScript
Overview
The Application Delivery environment requires more than simple CLI commands for managing
Application traffic. Often, an operator wants to make packet forwarding decisions based on
real-time events such as layer-3, layer-4, layer-7 data or server metrics such as current server load
statistics. These situations require a more dynamically programmable environment than
traditionally offered through built-in CLI commands.
In essence, the operators prefer programming the Application Forwarding Behavior rather than
statically provisioning it. The flexibility of programming the data-plane at layer-7 is invaluable in
dynamic data center environments as new applications come online.
The CLI-based interface of the Brocade Virtual ADX currently consists of a list of policy, rule, and
configuration commands that can be used to configure the application delivery switch for such
tasks as real server configuration, load-balancing metrics, as well as for traffic redirection and
transformation operations.
What is OpenScript
Brocade OpenScript provides data plane scripting functionality to manipulate traffic in
real-time.The Brocade OpenScript engine provides a programming framework and protocol level
APIs that allow you to create Perl scripts to customize the traffic handling capabilities of a Brocade
Virtual ADX. With this capability, you do not have to depend on Brocade to add needed functionality
to suit the needs of your network.
No separate license is required for OpenScript and is available to all customers with an active
service contract.
Why OpenScript uses Perl
Perl was chosen for OpenScript for the following primary reasons:
• Performance
• Extensibility
• Ubiquity
Performance
Because of the need to compile and interpret the program, scripting is an inherently slow process
in regards to performance. Consequently, scripting is often implemented as a multipass process.
This is preferable to the large overhead associated with the single pass execution model used with
command-based languages such as TCL that parse and execute each program statement on the