Application firewall scans application layer network traffic as it passes through the gateway and looks for content that matches configured keywords. When it finds a match, it performs the configured action. It can match text or binary content. When you configure application firewall, you create policies that define the type of applications to scan, the direction, the content or keywords to match. You could also optionally define the user or domain to match, and the action to perform.
Application Firewall provides application layer bandwidth management among other things. You can use application layer bandwidth management to control the amount of network bandwidth that can be used to transfer certain file types. This allows you to discourage non-productive traffic and encourage productive traffic on your network.
EXAMPLE: Online video streaming can consume a large amount of bandwidth. This article illustrates a method of throttling the bandwidth of such traffic using Application Firewall.
This release includes significant user interface changes and many new features that are different from the SonicOS 6.2 and earlier firmware. The below resolution is for customers using SonicOS 6.5 firmware.
NOTE: Bandwidth Management must be enabled before following this guide. Please, refer to How to Configure Bandwidth Management.
Defining a Match Object



Defining an Bandwidth Object

EXAMPLE: we have entered the following options. 
Defining an Action Object

NOTE: If throttling is the objective then the lowest possible figure should be above 1.845% of the total bandwidth. For eg. for a 1 Mbps pipe the lowest possible bandwidth is about 19 Kbps.
NOTE: If throttling is the objective then the lowest possible figure should be above 1.845% of the total bandwidth. For eg. for a 1 Mbps pipe the lowest possible bandwidth is about 19 Kbps.

Creating an Application Firewall Policy


How to Test:
To test this scenario go to https://www.youtube.com and watch a video. You should see alerts similar to the ones shown below in the log.
TIP: To verify the effectiveness of AF bandwidth management, try adjusting the Maximum Bandwidth value in the Bandwidth - Throttle action to larger and smaller values.You should see a marked improvement/degradation in the video streaming speed demonstrating that the bandwidth throttling is working as expected.
The below resolution is for customers using SonicOS 6.2 and earlier firmware. For firewalls that are generation 6 and newer we suggest to upgrade to the latest general release of SonicOS 6.5 firmware.
Defining an Application Object

Enabling Bandwidth Management on the WAN interface
Defining bandwidth management action
NOTE: If throttling is the objective then the lowest possible figure should be above 1.845% of the total bandwidth. For eg. for a 1 Mbps pipe the lowest possible bandwidth is about 19 Kbps.
NOTE: If throttling is the objective then the lowest possible figure should be above 1.845% of the total bandwidth. For eg. for a 1 Mbps pipe the lowest possible bandwidth is about 19 Kbps.

Creating an Application Firewall Policy

How to Test:
To test this scenario go to http://www.youtube.com and watch a video. You should see alerts similar to the ones shown below in the log.
TIP: To verify the effectiveness of AF bandwidth management, try adjusting the ‘Maximum Bandwidth’ value in the ‘Bandwidth - Throttle’ action to larger and smaller values.You should see a marked improvement/degradation in the video streaming speed demonstrating that the bandwidth throttling is working as expected.