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======Case 3. Bandwidth Management: DSCP Rules. Policing for Sites, Channels, and Subscribers======

Policing configuration is managed within the following subsections of the //Bandwidth Management// section:
  * //Sites Policing// — applies policing to traffic in the default channel (Default).
  * //Channels Policing// — applies policing to traffic within a specific channel.
  * //Subscribers Policing// — applies policing to traffic of a specific subscriber.

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Policing is conducted by traffic classes (by default, 8 classes), defined in the //Bandwidth Management → DSCP Rules// section.

DSCP Rules are set globally for all traffic passing through DPI in the //Bandwidth Management → DSCP Rules// section.\\
For each channel and subscriber, global DSCP rules can be overridden in the //Bandwidth Management → DSCP & Per-session Channel// and //Bandwidth Management → DSCP & Per-session Subscriber// sections, with session policing applicable as described in [[csg:use_case:webfilter_policing_rules#applying_session_policing_to_multiple_channels|Case 2. Applying Policies to Channels, Session Policing for Channels and Subscribers → Applying Session Policing to Multiple Channels]].

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The DSCP Rules section allows you to assign a protocol to a specific traffic class from cs0 to cs7. This traffic class is then used in policing profiles assigned to channels and subscribers.

Marking Modes:
  * Protocol — assigns a class/tag to each protocol individually
  * Protocol Group — assigns a class/tag to built-in protocol groups
  * Users Groups of Protocols — assigns a class/tag to custom protocol groups

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The “Priority” field defines the traffic class or actions to be taken with this protocol:
  * keep — retains the current priority value without modification (typically cs0)
  * drop — drops the traffic, with no statistics transmitted
  * cs0/cs7 — assigns a specific traffic class
  * af11/af12…ef — assigns a specific traffic class and uses additional 3 bits for traffic marking

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After configuring traffic classes, navigate to the //Bandwidth Management → Channels Policing// section, then to the desired channel.\\
In the opened editing window, select the type of policing mechanism; two policing mechanisms are available: TBF and HTB. Autocomplete can also be used.

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Enable the necessary classes according to the policing type.
HTB:\\ {{:csg:use_case:img_16.png?direct&900|}}

TBF:\\ {{:csg:use_case:img_17.png?direct&900|}}

To view the list of protocols contained in each class, there’s no need to go back to the //Bandwidth Management → DSCP Rules// section. You can check this by clicking “Applications CS//<number>// list”:\\ {{:csg:use_case:img_18.png?direct&600|}}