PCRF是通过下发什么字段让用户建立专载？
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PCRF是通过下发什么字段让⽤⼾建⽴专载？
Q：pcrf是通过下发什么字段让用户建立专载？
A：通过Gx接口参数：
Charging-Rule-Install -->Charging-Rule-Definition--->QoS-Information --->GBR/QCI for QoS信息，
Charging-Rule-Install -->Charging-Rule-Definition--->Flow-Information--->Flow-Description (媒体流描述信息) 。
另外，Rx接口还有一个参数用来区分业务，是p-cscf给pcrf发的aar里携带了AF-Application-Identifier，用于区分不同的业务。
【The AF-Application-identifier AVP (AVP code 504) is of type OctetString, and it contains information that identifies the particular
service that the AF service session belongs to. This information may be used by the PCRF to differentiate QoS for different application
services.
For example the AF-Application-Identifier may be used as additional information together with the Media-Type AVP when the QoS
class for the bearer authorization at the Gx interface is selected. The AF-Application-Identifier may be used also to complete the QoS
authorization with application specific default settings in the PCRF if the AF does not provide full Session-Component-Description
information.---29214
按照24229和29214的举例：AF-Application-Identifier取值可能是urn:urn-7:3gpp-service.ims.icsi.mmtel、media-type取值可能是audio或
video，用于业务的区分。】