Transcript CAMEL in GPRS prepaid service

CAMEL in GPRS prepaid service
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Outline
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Evolution of IN
GPRS overview
CAMEL in GPRS
Discussion
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Plain Old Telephone Service
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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
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Stored Program Control
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In the mid-1960s, 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
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Common Channel
Signaling
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In the mid-1970s, common channel signaling network
(CCSN) was introduced.
Signaling system number 7 (SS7) is the protocol that
runs over the CCSN.
SS7 network separates the call setup information and
talk path from the common trunk that runs between
switching systems.
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SS7 network components
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signal switching points (SSPs)—SSPs are telephone
switches equipped with SS7-capable software and
terminating signaling links. They generally originate,
terminate, or switch calls.
signal transfer points (STPs)—STPs are the packet
switches of the SS7 network. They receive and route
incoming signaling messages to destination.
signal control points (SCPs)—SCPs are databases
providing information necessary for advanced callprocessing capabilities
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SS7 network
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The Introduction of IN
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During the mid-1980s, 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
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Call Model
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PICs represent switching system states that a call goes
through from origination to termination.
SSPs check TDPs to see if there are 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
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in next step
GPRS logical architecture
SMS-GMSC
SMS-IWMSC
E
SM-SC
C
CAMEL GSMSCF
Gd
MSC/VLR
A
Gs
Iu
Uu
R
TE
HLR
MT
D
Ge
Gr
Iu
UTRAN
SGSN
Gc
Gi
Gn
Gb
TE
MT
R
BSS
Um
SGSN
Gn
PDN
GGSN
Ga
Ga
Gp
CGF
GGSN
Gf
TE
Billing
System
EIR
Other PLMN
Signalling Interface
Signalling and Data Transfer Interface
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Transmission plane in 2.5G
Application
IP
IP
Relay
SNDCP
Radio
indep
Radio
dep
SNDCP
Multiplexing layer
LLC
GTP-U
UDP
UDP
IP
IP
L2
L2
L1
L1
LLC
Relay
RLC
RLC
MAC
MAC
GSM RF
BSSGP
BSSGP
Network
Service
GSM RF L1bis
Network
Service
L1bis
Um
MS
GTP-U
Gb
BSS
Gn
SGSN
Gi
GGSN
Frame relay
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Signaling plane in 2.5G
GMM/SM
GMM/SM
LLC
LLC
Relay
RLC
RLC
MAC
MAC
GSM RF
BSSGP
BSSGP
Network
Service
GSM RF
L1bis
Network
Service
L1bis
Um
MS
Gb
BSS
2G-SGSN
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Multiplexing of network
protocols
IP/X.25
Signalling
Packet Data
Protocol
SMS
Signaling plane
Transmission plane
N-PDU
NSAPI
SNDCP
SNDC Header
NSAPI + Control
Data
LLC Header
Control
LLC Information
Data
SAPI
LLC
TLLI
RLC or BSSGP
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User plane in 3G
Application
E.g., IP,
PPP
E.g., IP,
PPP
Relay
Relay
PDCP
PDCP
GTP-U
GTP-U
GTP-U
GTP-U
RLC
RLC
UDP/IP
UDP/IP
UDP/IP
UDP/IP
MAC
MAC
AAL5
AAL5
L2
L2
L1
L1
ATM
ATM
L1
L1
Uu
MS
Iu-PS
UTRAN
Gn
3G-SGSN
ATM
Gi
3G-GGSN
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Control plane in 3G
GMM /
SM / SMS
GMM /
SM / SMS
Relay
RRC
RRC
RANAP
RANAP
RLC
RLC
SCCP
SCCP
MAC
MAC
Signalling
Bearer
Signalling
Bearer
L1
L1
AAL5
AAL5
ATM
ATM
Uu
MS
Iu-Ps
RNS
3G SGSN
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CAMEL architecture
Home Network
HLR
gsmSCF
MAP
CAP
gprsSSF
SGSN
Interrogating Network
MS
Visiting Network
Home/Interrogating/Visiting Network
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MAP/CAP protocol stack
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CAP has the same underlying protocol stack as MAP.
Ge interface is first defined in 3G, but didn’t appear
in 2.5G.
MAP
MAP
CAP
CAP
TCAP
TCAP
TCAP
TCAP
SCCP
SCCP
SCCP
SCCP
MTP3
MTP3
MTP3
MTP3
MTP2
MTP2
MTP2
MTP2
L1
L1
L1
L1
HLR
gprsSSF
SGSN
Gr
Ge
gsmSCF
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Overall CAMEL Architecture
gsmSCF
CAP Interface
GPRS
Dialogue
Handler
Internal CAP Interface
gprsSSF
Internal Interface
MobileStation
SGSN
GTP
GGSN
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Detection Points (DPs)
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GPRS events maybe made visible to gsmSCF.
DPs are points at which these events are
detected.
DPs can be armed to notify gsmSCF GPRS
event was encountered, and to allow gsmSCF
to influence subsequent handling of GPRS
session/PDP Context.
If DP isn’t armed, processing entity continues
processing without gsmSCF involvement at
the DP.
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Detection Points (DPs)
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3 different types of DP:
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Trigger Detection Point-Request (TDP-R)
Event Detection Point-Request (EDP-R)
Event Detection Point-Notification (EDP-N)
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Detection Points (DPs)
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TDP-R
 Statically armed, initiate a CAMEL control relationship
 When GPRS event is encountered, processing is suspended
EDP-R
 Dynamically armed within CAMEL control relationship
 When GPRS event is encountered, processing is suspended
and gprsSSF waits for inst from gsmSCF
EDP-N
 Dynamically armed within CAMEL control relationship
 When GPRS event is encountered, processing is not
suspended.
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GPRS Attach/Detach State
Model
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3 DPs are defined:
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Detached
DP Attach
DP Change of Position
Detach
GPRS session
DP Detach
Attach request
AD_Exception
Attach
User- or network initiated
detach
Attached
Intra SGSN Routeing
area update
Inter SGSNRouteing area
update
Change of Position GPRS Session
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GPRS PDP Context State
Model
Idle
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4 DPs are defined:
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PDP Context
Setup Req
DP PDP Context
PDP Context Est.
PDP_Context_
Context
C_Exception
Establishment PDP
Setup
Disconnection
PDP Context
DP PDP Context
Setup Ack.
PDP Context Est. Ack.
Establishment Ack
User or network
PDP_Context_
initiated disc.
DP PDP Context
Established
Disconnection
Routeing area update
Change of Position Context
DP Change of
Position Context
Routeing area update
Change of
Position context
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GPRS CAMEL Scenarios
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2 scenarios for CAMEL control of GPRS
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Scenario 1
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Scenario 2
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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.
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GPRS CAMEL Scenario 1
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Involves Attach/Detach state model
Uses less resource (tcap dialogue)
More complicated when implementation
SGSN / SSP
A/D
SM
PDP#1
SM
PDP#2
SM
GPRS Dialogue
SCP
Information flow related to
the Session
Information flow related to
PDP Context #1
Information flow related to
PDP Context #2
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GPRS CAMEL Scenario 2
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Doesn’t involves Attach/Detach state model
Uses more resource (tcap dialogue)
Simpler when implementation
SGSN / SSP
PDP#1
SM
PDP#2
SM
GPRS Dialogue #1
SCP
Information flow related to
PDP context #1
Information flow related to
PDP context #2
GPRS Dialogue #2
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GPRS Attach
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The message sequence chart is too large to fit in this
slide. Please see the supplementary document from
3GPP 23060 spec.
Notice the “Insert subscriber data” procedure, GPRSCSI (CAMEL Subscription Information) is sent from
HLR to SGSN.
2.5G HLR does not keep GPRS-CSI, nor does it send
GPRS-CSI to SGSN.
3G HLR could keep GPRS-CSI, also it sends GPRS-CSI
when doing “Insert subscriber data” procedure.
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GPRS-CSI
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GPRS-CSI contains following information
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gsmSCF Address
Service Key
Default GPRS Handling
TDP List
CAMEL Capability Handling
CSI state
Notification flag
gsmSCF address list for CSI
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PDP Context Activation in 2.5G
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C1 :DP for CAMEL_GPRS_PDP_Context_Establishment
C2 :DP for CAMEL_GPRS_PDP_Context_Establishment_Acknowledgement
MS
BSS
2G-SGSN
2G-GGSN
1. Activate PDP Context Request
C1
2. Security Functions
3. Invoke Trace
4. Create PDP Context Request
4. Create PDP Context Response
7. BSS Packet Flow Context Procedures
C2
9. Activate PDP Context Accept
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PDP Context Activation in 3G
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C1 :DP for CAMEL_GPRS_PDP_Context_Establishment.
C2 :DP for CAMEL_GPRS_PDP_Context_Establishment_Acknowledgement
MS
UTRAN
3G-SGSN
3G-GGSN
1. Activate PDP Context Request
C1
4. Create PDP Context Request
4. Create PDP Context Response
5. Radio Access Bearer Setup
6. Invoke Trace
8. Update PDP Context Request
8. Update PDP Context Response
C2
9. Activate PDP Context Accept
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CAMEL procedures for
charging activities
Procedure
ApplyChargingGPRS
ApplyChargingReportGPRS
InitialDPGPRS
ContinueGPRS
EventReportGPRS
RequestReportGPRSEvent
ssf -> scf scf ->ssf
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Discussion
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