Express YourSelf !

*  LTE PCC = PCRF (PDP Policy Decision Point) + PCEF + OCS + OFCS

* 4G PCRF  = 3G PDF + 3G CRF

* PDF

- allow/reject media req

- new / existing pdp context for media

- check against max allowed resource allocation 

- lower BW for heavy-bw apps, during peak hours

Policies

- QoS

- BW Control

- Subscriber-aware

- Application gating

CRF

- charging rules: based on: Customer Service Level Agreement, time of day, n/w condition, volume of usage of high BW application, QoS gurantees, roaming status. 

PCRF 

(1) service flow detection 

(2) Policy enforcement - PDF 

(3) flow based charging - CRF

- real time management of (1) n/w and (2) subscribe policy

- route and prioritize n/w traffic. 

- subscriber context = device + network + location + billing data

- input for revenue assurance + 

- bw management: real time appropriate bw allocation to each service

- charging rules

In PCRF:

Memory = Subscriber DB

DSC (Diameter Signalling Controller) = nervous system

Brain = policy

Interfaces

Gx: PCEF (P-GW)

Gxx: BBERF (S-GW)

Rx: AS

Sp: SPR

Sd: TDF Traffic Detection Function

Sy: OCS

Gz: PCEF - OFCS

Gy: PCEF - OCS

Ud: UDR User Data Repository

Ref:

https://www.netmanias.com/en/post/techdocs/10997/lte-pcrf/policy-and-charging-rules-function-pcrf-in-lte-epc-core-network-technology