> # Information About Service Policy Definition

> Service policies are specified using policy maps. Policy maps provide an ordered mapping of class maps to service levels. The order of the class maps within a policy map is important to determine the order in which the frame is compared to class maps. The first matching class map has the corresponding priority marked in the frame. You can specify multiple class maps within a policy map, and map a class map to a high, medium, or low service level. The default priority is low. Alternatively, you can map a class map to a differentiated services code point (DSCP). The DSCP is an indicator of the service level for a specified frame.

> Service policies are specified using policy maps. Policy maps provide an ordered mapping of class maps to service levels. You can specify multiple class maps within a policy map, and map a class map to a high, medium, or low service level. The default priority is low. The policy map name is restricted to 63 alphanumeric characters.

> As an alternative, you can map a class map to a differentiated services code point (DSCP).The DSCP is an indicator of the service level for a specified frame. The DSCP value ranges from 0 to 63, and the default is 0. A DSCP value of 46 is disallowed.

> The order of the class maps within a policy map is important to determine the order in which the frame is compared to class maps. The first matching class map has the corresponding priority marked in the frame.

> Note Refer to http://www.cisco.com/en/US/tech/tk543/tk757/technologies_tech_note09186a00800949f2.shtml for further information on implementing QoS DSCP values.

> Note Class maps are processed in the order in which they are configured in each policy map.

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