CAMEL in GPRS prepaid service ghleealumni csie nctu

CAMEL in GPRS prepaid service ghlee@alumni. csie. nctu. edu. tw 1

Outline n n Evolution of IN GPRS overview CAMEL in GPRS Discussion 2

Plain Old Telephone Service n n n Service logic were hardwired in switching systems. Network operators discuss services customers required with switch vendors. (no standard) Once services were implemented, they were not easily modified. service logic hardwired 3

Stored Program Control n n n In the mid-1960 s, stored program control (SPC) switching systems were introduced. As a result, it was easier to introduce new services. Service logic was not modular. service logic programmable 4

Common Channel Signaling n n n In the mid-1970 s, common channel signaling network (CCSN) was introduced. Signaling system number 7 (SS 7) is the protocol that runs over the CCSN. SS 7 network separates the call setup information and talk path from the common trunk that runs between switching systems. 5

SS 7 network components n n n signal switching points (SSPs)—SSPs are telephone switches equipped with SS 7 -capable software and terminating signaling links. They generally originate, terminate, or switch calls. signal transfer points (STPs)—STPs are the packet switches of the SS 7 network. They receive and route incoming signaling messages to destination. signal control points (SCPs)—SCPs are databases providing information necessary for advanced callprocessing capabilities 6

SS 7 network 7

The Introduction of IN n n During the mid-1980 s, Telcordia Technologies responded to RBOCs’s request and developed the concept of Intelligent Network 1 (IN/1). Service logic splits from switching system, now resides in service control points (SCP). service logic now here 8

Call Model n n n PICs represent switching system states that a call goes through from origination to termination. SSPs check TDPs to see if there any active triggers. If an active trigger is detected, normal switching system call processing is suspended until the SSP and SCP complete communications. SSP suspended, and ask SCP what to do 9 in next step

GPRS logical architecture 10

Transmission plane in 2. 5 G Radio indep Multiplexing layer Radio dep Frame relay 11

Signaling plane in 2. 5 G 12

Multiplexing of network protocols IP/X. 25 Signaling plane Transmission plane 13

User plane in 3 G ATM 14

Control plane in 3 G 15

CAMEL architecture 16

MAP/CAP protocol stack n n CAP has the same underlying protocol stack as MAP. Ge interface is first defined in 3 G, but didn’t appear in 2. 5 G. 17

Overall CAMEL Architecture 18

Detection Points (DPs) n n n GPRS events maybe made visible to gsm. SCF. DPs are points at which these events are detected. DPs can be armed to notify gsm. SCF GPRS event was encountered, and to allow gsm. SCF to influence subsequent handling of GPRS session/PDP Context. If DP isn’t armed, processing entity continues processing without gsm. SCF involvement at the DP. 19

Detection Points (DPs) n 3 different types of DP: n n n Trigger Detection Point-Request (TDP-R) Event Detection Point-Request (EDP-R) Event Detection Point-Notification (EDP-N) 20

Detection Points (DPs) n n n TDP-R n Statically armed, initiate a CAMEL control relationship n When GPRS event is encountered, processing is suspended EDP-R n Dynamically armed within CAMEL control relationship n When GPRS event is encountered, processing is suspended and gprs. SSF waits for inst from gsm. SCF EDP-N n Dynamically armed within CAMEL control relationship n When GPRS event is encountered, processing is not suspended. 21

GPRS Attach/Detach State Model n 3 DPs are defined: n n n DP Attach DP Change of Position GPRS session DP Detach 22

GPRS PDP Context State Model n 4 DPs are defined: n n DP PDP Context Establishment Ack DP PDP Context Disconnection DP Change of Position Context 23

GPRS CAMEL Scenarios n 2 scenarios for CAMEL control of GPRS n Scenario 1 n n Scenario 2 n n n Allows CAMEL control of GPRS session and of multiple PDP contexts within 1 GPRS dialogue Allows CAMEL control of a single PDP contexts Multiple PDP contexts are controlled via multiple GPRS dialogues. Scenario 1 and scenario 2 are mutually exclusive. 24

GPRS CAMEL Scenario 1 n n n Involves Attach/Detach state model Uses less resource (tcap dialogue) More complicated when implementation 25

GPRS CAMEL Scenario 2 n n n Doesn’t involves Attach/Detach state model Uses more resource (tcap dialogue) Simpler when implementation 26

GPRS Attach n n The message sequence chart is too large to fit in this slide. Please see the supplementary document from 3 GPP 23060 spec. Notice the “Insert subscriber data” procedure, GPRSCSI (CAMEL Subscription Information) is sent from HLR to SGSN. 2. 5 G HLR does not keep GPRS-CSI, nor does it send GPRS-CSI to SGSN. 3 G HLR could keep GPRS-CSI, also it sends GPRS-CSI when doing “Insert subscriber data” procedure. 27

GPRS-CSI n GPRS-CSI contains following information n n n n gsm. SCF Address Service Key Default GPRS Handling TDP List CAMEL Capability Handling CSI state Notification flag gsm. SCF address list for CSI 28

PDP Context Activation in 2. 5 G n n C 1 : DP for CAMEL_GPRS_PDP_Context_Establishment C 2 : DP for CAMEL_GPRS_PDP_Context_Establishment_Acknowledgement 29

PDP Context Activation in 3 G n n C 1 : DP for CAMEL_GPRS_PDP_Context_Establishment. C 2 : DP for CAMEL_GPRS_PDP_Context_Establishment_Acknowledgement 30

CAMEL procedures for charging activities Procedure Apply. Charging. GPRS Apply. Charging. Report. GPRS Initial. DPGPRS Continue. GPRS Event. Report. GPRS Request. Report. GPRSEvent ssf -> scf ->ssf 31

Discussion 32