A BSS Packet Flow Context contains the aggregate BSS QoS profile that is identical or similar for one or more activated PDP contexts. A BSS Packet Flow Context can be shared between several mobiles; several BSS Packet Flow Contexts can be defined. A BSS Packet FLow Context may be created, modified, or deleted every time a PDP context is activated, modified, or deleted.
A packet flow identifier (PFI), assigned by the SGSN, is used to identify each BSS Packet Flow Context. The PFI is assigned to the BSS at the creation of the BSS Packet Flow Context. It is assigned to the mobile when accepting the activation of the PDP context.
Three PFI values are reserved for best-effort service, SMS, and signaling.
Whenever the BSS receives an LLC PDU to transmit either in the direction of the SGSN or in the direction of the mobile, it deduces the QoS profile to use for the transmission from the PFI associated to the PDU.
The BSS Packet Flow contect concept has been introduced in the GPRS Release 99 recommendations.