Bandwidth Throttling Using Classes
Bandwidth throttling can be performed on Web Gateway using classes, which cover ranges of data transferring speed.
NOTE: Bandwidth throttling is also known as bandwidth control.
A bandwidth class can, for example, cover the speed range between 1 and 1000 Kbps, while another class covers 1001 to 2000 Kpbs. Using an event in a rule, you can configure that particular web objects are uploaded or downloaded with the speed of either of these two classes or any other class that you have created.
You can also group classes and subordinate them to parent classes, assigning different priorities to the classes in a group.
Bandwidth throttling using classes can be configured for all directions that web traffic flows into. The speed of downloads requested by clients of Web Gateway can be throttled, as well as the speed of uploads.
This throttling method can be used for throttling transferring speed, but also for ensuring a minimum speed when web objects are uploaded or downloaded. In most cases, however, its main purpose will be limiting the speed of voluminous downloads from the web.
Bandwidth throttling using classes is available for most of the different network modes that can be configured for the proxy functions of Web Gateway. These modes include the explicit proxy mode, the proxy HA mode, and the transparent modes.
Bandwidth throttling using classes can also be applied to traffic that is not using the proxy functions of Web Gateway.
Events in rules for bandwidth throttling using classes
The following events are available for use in rules that control bandwidth throttling using classes:
- Bandwidth.FromClient — Limits the speed of data transfer from a client to the appliance
- Bandwidth.ToServer — Limits the speed of data transfer from the appliance to a web server
- Bandwidth.FromServer — Limits the speed of data transfer from a web server to an appliance
- Bandwidth.ToClient — Limits the speed of data transfer from the appliance to a client
When these events are used in rules, they take the name of a bandwidth class as a parameter. This way traffic can be throttled in any direction according to the limits that are configured for the respective class.
Bandwidth throttling rule for downloads
The following is an example of a bandwidth throttling rule. It applies bandwidth throttling using classes to downloads of large files from the web.
Name Limit transferring speed for large downloads Criteria Action Event Body.Size greater than 10000000" –> Continue Bandwidth.FromServer ("Large")
The rule uses the Bandwidth.FromServer event to limit the speed at which downloads from a web server are performed.
If the size of a web object that is sent as the body of a response from the server exceeds 10 MB, the transferring speed is limited to a particular speed range. This speed range is the range that you configured for the bandwidth class named Large, for example, between 1 and 1000 Kbps.