A system comprising: at least one processor; and one or more computer-readable storage media including instructions stored thereon that, responsive to execution by the at least one processor, cause the system to perform operations including: generating an initialization service policy for controlling data in a communication session within a communication network, and propagating the initialization service policy to one or more components of the communication network; receiving a notification that the communication session is initiated in the communication network according to the initialization service policy; generating, in response to the notification, an updated service policy for the communication session; identifying components included in a routing path for a media flow of the communication session; propagating the updated service policy to the identified components to be applied to the media flow of the communication session in place of the initialization service policy so that media of the communication session is exchanged according to the updated service policy instead of the initialization service policy; and the initialization service policy specifying that the media flow of the communication session is to be tagged with a first service priority designator to generate a tagged media flow as a first service priority, and the updated service policy specifying that the media flow of the communication session is to be retagged with a second service priority designator to generate a tagged media flow as a second service priority. at least one processor; and one or more computer-readable storage media including instructions stored thereon that, responsive to execution by the at least one processor, cause the system to perform operations including: generating an initialization service policy for controlling data in a communication session within a communication network, and propagating the initialization service policy to one or more components of the communication network; receiving a notification that the communication session is initiated in the communication network according to the initialization service policy; generating, in response to the notification, an updated service policy for the communication session; identifying components included in a routing path for a media flow of the communication session; propagating the updated service policy to the identified components to be applied to the media flow of the communication session in place of the initialization service policy so that media of the communication session is exchanged according to the updated service policy instead of the initialization service policy; and the initialization service policy specifying that the media flow of the communication session is to be tagged with a first service priority designator to generate a tagged media flow as a first service priority, and the updated service policy specifying that the media flow of the communication session is to be retagged with a second service priority designator to generate a tagged media flow as a second service priority. receiving a notification that the communication session is initiated in the communication network according to the initialization service policy; generating, in response to the notification, an updated service policy for the communication session; identifying components included in a routing path for a media flow of the communication session; propagating the updated service policy to the identified components to be applied to the media flow of the communication session in place of the initialization service policy so that media of the communication session is exchanged according to the updated service policy instead of the initialization service policy; and the initialization service policy specifying that the media flow of the communication session is to be tagged with a first service priority designator to generate a tagged media flow as a first service priority, and the updated service policy specifying that the media flow of the communication session is to be retagged with a second service priority designator to generate a tagged media flow as a second service priority.