PCEF-AAA Interface Specifications (Version 1.0)

April 14, 2011

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Contents 1 Scope ......................................................................................................................................... 1 Definitions and Normative Reference ............................................................................................... 1

Definitions ................................................................................................................................. 1 Normative Reference ................................................................................................................ 1

Abbreviations .................................................................................................................................... 2 2 PrePaid Packet Data Service System Architecture ................................................................... 2 3 Service Description ................................................................................................................... 2

3.2 Service Characteristics ........................................................................................................ 2 4 Service Flow Chart .................................................................................................................... 3

5.1 Activating/Deactivating Service of the PPS User ............................................................... 3 5.2 PrePaid Packet Data Service Authentication ...................................................................... 3 5.3 PrePaid Packet Data Service Charging ............................................................................... 4

5.3.1 Charging without Rate Changeover ......................................................................... 4 5.3.2 Charging with Rate Changeover .............................................................................. 6

5 Charging Principles ................................................................................................................... 9 6.1 Charging PrePaid Packet Data Service User by Duration .................................................. 9 6.2 Charging PrePaid Packet Data Service User by Traffic .................................................... 10 6.3 Activating/Deactivating Service of the PPS User ............................................................. 10

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1 Scope

These Technical Specifications introduce the basic concepts of the PrePaid Packet Data Service on

the CDMA mobile intelligent network, and the contents related to business processes and charging.

The technical specifications herein are formulated on the basis of the interface mode specified in

the “3GPP2 P.S0001-A V3.0.0, Wireless IP Network Standard”, and are used as a guidance for the

research, development and implementation of the PrePaid Packet Data Service. At present, the

service scope of the PrePaid Packet Data Service covers data service, namely, the PPS user makes

use of the call process of the CDMA wireless data service through PDSN and AAA server. These

Specifications do not deal with the specific processes in the PDSN and AAA server.

Definitions and Normative Reference

Definitions

PrePaid Packet Data Service: Packet prepaid service, a service where the network user pays first, then the operator maintains the account information of the user, and the user enjoys the packet data service based on the account balance. Prepaid server: An entity which maintains the configuration and state of the user, and interacts with the prepaid client to implement the authentication and charging for the PPS user. Prepaid client: An entity which requests the prepaid server to authorize the PPS of the user, and trace and handle the service use of the user in real time in the core network. Prepaid user: The network user who pays the service provider before enjoying the CDMA packet service.

Normative Reference The clauses in the following documents are incorporated by reference into this Standard. For the specifically dated reference documents, all the revision orders (excluding the corrective contents) or revision versions subsequent to date are not applicable to this Standard. However, we encourage the parties to the agreement concluded on the basis of this Standard to consider whether to use the latest versions of such documents. For the reference documents not specifically dated, their latest versions are applicable to this Standard. [1] 3GPP2 P.S0001-A V3.0.0, Wireless IP Network Standard. [2] RFC2865, Remote Authentication Dial In User Service (RADIUS). [3] RFC2866, RADIUS Accounting.

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Abbreviations The following abbreviations are applicable to the specifications herein.

AAA Authentication, Authorization and Accounting

CDMA Code Division Multiple Access

HA Home Agent

HAAA Home AAA

FAAA Visited AAA

MS Mobile Station

PPC Prepaid Client

PPS Prepaid Server

PDSN Packet Data Serving Node

SCP Service Control Point

PCEF Policy and Charging Enforcement Function

2 PrePaid Packet Data Service System Architecture The PrePaid Packet Data Service is in a client/server structure. AAA and PCEF system shall interface as stated herein. PPS(prepaid server) represents PCEF in following chapter.

3 Service Description

3.2 Service Characteristics

(1) Minimum threshold value: The system can specify a minimum threshold value of the PrePaid

Packet Data Service. When the balance of the PPS account is lower than the minimum

threshold value, the subscriber will be disabled from using the packet data PPS.

(2) Threshold value of each consumption: The system can specify a consumption threshold value

of a PPS. When the PrePaid Packet Data Service user performs data communication, the user

can consume the duration or traffic volume up to the threshold specified by the system.

(3) Judging balance: When the balance of the PPS account is higher than the threshold, after the

user originates a call or receives a call, the system will judge whether the balance of the PPS

account is enough for this attempt of data communication. If not enough, the system will

reject the user in using the data service.

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4 Service Flow Chart

5.1 Activating/Deactivating Service of the PPS User

5.2 PrePaid Packet Data Service Authentication

The SCP implements the function of rate conversion. Through the Access-Request message

(carrying the prepayment attribute) of the Radius protocol, the PPS enables to query the account

state at the SCP and apply for the quota of time or traffic.

PDSN HAAA

Access-Request (PPAC)a

Access-Accept (PPAC)

PPS SCP

Access-Request(PPAC)b

Access_Accept (PPAC)

c

d

e

f

Access-Request

Access_Accept

Fig. 5-1 PPS Authentication Flow With PPC Residing at PDSN (SCP Implements the Function of Rate

Conversion)

a) PDSN has the PPS capability. It can send the Access-Request message to the HAAA, and

carry the PrePaidAccountingCapability (PPAC) attribute which indicates the PPS capabilities

supported by the HAAA PPS client.

b) The HAAA performs conventional authentication and authorization. If the user profile reveals

that it is a PPS user, the Access-Request message should be forwarded to the PPS. The PPS

does not need to authenticate the user identity, but check the validity of the message through

the “Message Authenticator (80)” attribute. (See also RFC2869.)

c) The PPS checks the PPAC, and sends the Access-Request message to SCP to authenticate the

state of the user account, and can also carry the PPAC of the user to let the SCP authorize the

PPS capabilities.

d) The SCP checks whether the user account has valid state and balance, and, after the check is

passed, returns the Access-Accept message to the PPS, which may contain the PPAC

authentication information.

e) The PPS returns the prepayment authentication information, and maintains the online state of

the user.

f) The HAAA implements the authentication, and returns the authentication information.

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5.3 PrePaid Packet Data Service Charging

5.3.1 Charging without Rate Changeover

The SCP implements the function of rate conversion. Through the Access-Request message

(carrying the prepayment attribute) of the Radius protocol, the PPS enables to apply for the quota

of time or traffic.

MS PDSN HAAA PPS

Accounting-Request/Response (Start)

SCP

Access-Request(PPAQ,VQ/DQ=0)

Access-Request(PPAQ,VQ/DQ=0)

Access-Accept(PPAQ,VQ/DQ,VT/DT)

Access-Accept(PPAQ,VQ/DQ,VT/DT)

b

Access-Request(PPAQ,VQ/DQ=used)

Access-Request(PPAQ,VQ/DQ=used)

Access-Accept (PPAQ,VQ/DQ,VT/DT)

Access-Accept (PPAQ,VQ/DQ,VT/DT)

Thresh reached

Access-Request(PPAQ,VQ/DQ=used)

Access-Request(PPAQ,VQ/DQ=used)

Access-Accept(PPAQ,VQ/DQ=VT/DT)

Access-Accept(PPAQ,VQ/DQ=VT/DT)

Thresh reached

Access-Request(PPAQ,VQ/DQ=0)

a

Access-Accept(PPAQ,VQ/DQ,QID)

Access-Request(PPAQ,VQ/DQ=used)

Access-Request(PPAQ,VQ/DQ=used)

Access-AcceptAccess-Accept

Thresh reached

Access-Request(PPAQ,VQ/DQ=0,QID)

Access-Accept(PPAQ,VQ/DQ=0,QID)

Accounting- Response(Stop)

c

d

e

f

gh

l

m

n

o

i

j

k

Access-Request(PPAQ,VQ/DQ=used)

Access-Accept

p

Fig. 5-2 Charging Flow Without Rate Changeover (SCP Implements the Function of Rate Conversion)

a) Upon completion of the PPS authentication / authorization, a “RADIUS Accounting-Request

(Start)” message will be sent from the PDSN, as similar to the establishment of conventional

packet data session.

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b) The PPC (PDSN) sends an Access-Request message which is transmitted transparently to PPS

via HAAA, and the message contains a manufacturer attribute (VQ/DQ=0) with updated quota.

c) The PPS sends an Access-Request message to SCP, and the message contains the manufacturer

attribute (VQ/DQ=0，VT/DT=0) with updated quota.

d) According to “VQ/DQ=0, VT/DT=0”, the SCP judges whether this is the balance of the account

of the PPS user. According to the rules of distributing the account balance, the SCP calculates the

balance (traffic/time) used for the account data. The SCP assigns a value to the VQ/DQ attribute,

and checks whether this message carries the QID attribute so as to judge whether this is the first

request of the user. If it is the first request, the SCP will allocate the globally unique QID for this

user, and send a responding Access-Accept (PPAQ) message to the PPS.

e) After the PPS receives the account balance returned by SCP, the PPS allocates the initial

traffic/duration quota and threshold. The allocated quota is stored on the PPS as an authorized

quota.

f) When the quota in use hits the threshold of the previously allocated quota, the PDSN sends an

“Access-Request” message containing “VQ=threshold” to the PPS.

g) The PPS saves this threshold as the balance in use. The PPS updates the account balance, and, if

any balance is available, allocates a new quota to the PPC. The quotas VQ/DQ and VT/DT

returned in the Accept-Accept message are the sum of the previous quotas and this quota.

h) If the PPS judges that the available balance of this account reaches the set value of the balance

requested to SCP, the PPS will send the Access-Request message which carries the manufacturer

attribute (VQ/DQ=0, VT/DT = Balance Sum, where Balance Sum is the sum of balances

received by the PPS. QID is obtained from DBS previously).

i) According to QID, the SCP judges that the PPS requests balance again, and obtains the state of

allocating balance of the user according to QID, and handles the allocation rules according to the

allocation state, then judges that no further balance should be allocated for the user, and returns

the Access-Accept (PPAQ,QID, VQ/DQ=0) message.

j) When the quota in use hits the threshold of previously allocated quota, the PDSN sends an

“Access-Request (PPAQ)” message containing “VQ=threshold” to the PPS.

k) The PPS finds out that the account balance equals the authorized quota and no further quota is

available, it will return the previously authorized quota in the “Access-Accept” message, which

contains VQ/DQ, and set the threshold VT/DT to be identical with the VQ/DQ.

l) When the last threshold is hit, in view of “VQ=VT (or DQ=DT)” in the last quota update, the

PDSN knows that the user has no available balance. The PDSN sends an Access-Request

message to PPS, where the sub-attribute UR (Update-Reason) in the attribute PPAQ is set to

“Quota reached”. The PPS discovers that the sub-attribute UR (Update-Reason) of PPAQ is

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“Quota reached”, and knows that the quota is used up, then allocates no further quota, and replies

with an Access-Accept message which carries no PPAQ attribute.

m) The PPS treats the VQ/DQ in “Access-Request” as the balance in use. Now the account

balance equals the quota in use, and the PPS forwards this message to SCP.

n) The SCP performs pricing treatment and updates the account, and replies with an

Access-Accept message to the PPS to tell the end of this PPS packet data session.

o) The PPS receives the Access-Accept message and performs user state treatment, and forwards

Access-Accept to PDSN.

p) The PDSN receives the Access-Accept message, and releases the corresponding resources and

sends an Accounting-Request (Stop) message (the same as the conventional postpayment

charging procedure).

5.3.2 Charging with Rate Changeover

PrePaid Packet Data Service supports charging with rate changeover. The rate conversion is

performed by SCP. The SCP must support the rate changeover feature, and save the rate

changeover information. These Specifications do not deal with the calculation strategy that

involves conversion of exchange rate.

The rate changeover covers the following circumstances:

1. Charging by time, and the rate differs between time segments.

2. Charging by traffic, and the rate differs between time segments.

3. Charging by time, and the rate differs between consumption amounts.

4. Charging by traffic, and the rate differs between consumption amounts.

Fig. 5-3 illustrates the circumstance of “charging by traffic, and the rate differs between time

segments” in case of supporting the rate conversion function. The PPS allocates the traffic quota

for the PPC, and needs to notify the time interval with the latest rate changeover (the time interval

between the rate changeover point and the Time Stamp (G4) attribute) to the PPC through the TSI

sub-attribute of PPAQ prepaid service attribute. The PPC must record traffic used after the rate

changeover time point, and notifies it to the PPS through the VUATS sub-attribute of the PPS

attribute of PPAQ at the next time of applying for traffic quota. The PPS re-calculates the sum of

charges consumed by the user, and allocates a quota for the PPC again according to the balance

and allocation strategy.

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PDSN HAAA

a 11:00

PPS SCP

b

Quotathreshold c 11:35

e

Usequota

Allocatequota

0K

20 yuan/200K

Fundaccount

41 yuan

Allocate fund/convert traffic

0K

21 yuan

0 yuan/0K

50K 40K20 yuan/220K

0K 0K

Quota (PPAC, PPAQ(VQ=50K, VT=40K TSI=3600))

Access-Request (PPAQ(VQ=40K))

Access-Accept PPAQ(VQ=100K, VT=90K TSI=1500) 100K 40K

Rate changeover point 12:00

Access Request (PPAQ(VQ=90K,VUATS=10K))

Access-AcceptPPAQ（VQ=150K,VT=140K)

e 19:00

20 yuan/240K 150K 80K/10K

Access Request (PPAQ(VQ=140K,VUATS=20K))

Access-Accept PPAQ(VQ=200K, VT=190K TSI=50400)

150K 100K/40Kg

20 yuan/250K 200K 100K/40K

h 22:00

250K

40 yuan/475K

Access-Request (PPAQ(VQ=190K))

Access-AcceptPPAQ（VQ=250K,VT=240K)

20 yuan/275K

150K/40K

d

i

j 23:00

k

Access-Request (PPAQ(VQ=540K))1990K

Access-Accept

250K 500K/40K

IP Datagrams

IP Datagrams

IP Datagrams

IP Datagrams

IP Datagrams

21 yuan

l

DS_GET_BLANCE

f

1 yuan

......

m

12 yuann

o

DS_CHARGE_resp

DS_CHARGE

After passing the authentication and authorization,the PPS starts

DS_GET_BLANCE-desp

Quotathreshold

Quotathreshold

Quotathreshold

Quotathreshold

Quotathreshold

Rate changeover point 21:00

Fig. 5-3 Charging Procedure With Rate Changeover

a) The PPS implements the state check of the PrePaid Packet Data Service account, and allocates

the initial quota, and determines the charging mode by interacting the PPAC attribute between

PDSN (PPC) and PPS. For example, the procedure selects charging by traffic and supports the

rate changeover, so one yuan is entitled to use a traffic volume of 10K from 12:00 to 21:00 of

each day, and 20K from 21:00 to 12:00 of each day. The current time is 11:00, which is 3600

seconds away from the rate changeover point 12:00. The PPS uses the minimum rate of the

latest rate changeover point to calculate the maximum allocable traffic. The current nearest

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rate changeover point is 12:00, and the minimum rate is 10K/yuan. The PPS calculates out the

allocable traffic 200K (10*20), the allocated traffic quota VQ=50K, the traffic threshold

VT=40K, and the time interval of the rate changeover point is TSI = 3600 seconds.

b) The packet data service starts, and the PDSN (PPC) records the traffic volume consumed by

the user.

c) The PDSN (PPC) detects that the traffic volume consumed by the user has reached the

threshold of 40K, and sends an Access-Request (PPAQ (VQ=40K)) quota request message.

The PPS receives the quota request message, and records the traffic quota of the user, then

calculates the consumption sum by using the consumption traffic to divide the rate (which is 2

yuan, namely, 40/20), and the remaining sum is 18 yuan. By multiplying the minimum rate

with the balance, plus the quota in use, the maximum traffic quota (10*18+40) 220K is

worked out. The PPS can allocate another traffic quota 50K to the PPC. After being

accumulated with the previously allocated quota 100K, the traffic threshold is 90K. The

current time is 11:35, which is 1500 seconds away from the rate changeover point 12:00. The

PPS replies with the message “Access-Accept (PPAQ(VQ=100K, VT=90K),

PTS(TSI=1500S))”.

d) The PDSN records the consumption amount of the PPS user, and must record the traffic

volume consumed after the rate changeover point once detecting the cross of rate changeover

point.

e) The PDSN (PPC) detects that the traffic volume consumed by the user has reached the

threshold of 90K, and sends an “Access-Request (PPAQ (VQ=90K), PTS (VUATS=10K))”

quota request message.

f) The PPS records the consumed traffic of each rate, and calculates out the consumed sum

(80/20+10/10), namely, 5 yuan, according to the corresponding rate, so the remaining sum is

15 yuan. By multiplying the minimum rate with the remaining sum, plus the consumed quota,

the maximum traffic quota (10*15+90)=240K is worked out. This way, another traffic quota

equivalent to 50K is allocable. After being accumulated with the previously allocated quota

150K, the traffic threshold is 140K. The current time is 19:00, and the rate changeover time

interval is (from 21:00) 7200 seconds. The PPS replies with the message Access-Accept

(PPAQ(VQ=150K, VT=140K),PTS(TSI=7200S)).

g) The PDSN records the consumption amount of the PPS user, and must record the traffic

volume consumed after the rate changeover point once detecting the cross of rate changeover

point 21:00.

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h) The PDSN (PPC) detects that the traffic volume consumed by the user has reached the

threshold of 140K, and sends an “Access-Request (PPAQ(VQ=140K), PTS(VUATS=20K))”

quota request message.

i) The PPS saves the traffic consumed at the rate changeover point, 100K at the rate of

20K/yuan, 40K at the rate of 10K/yuan, and calculates the new allocable traffic 250K. The

current time is 22:00, another allocable traffic quota is 50K, as accumulated to 200K, which is

50400 seconds away from the rate changeover point (12:00 of the next day).

j) The PPC detects that the traffic volume consumed by the user has reached the threshold of

190K, and sends an Access-Request (PPAQ (VQ=190K)) quota request message. The PPS

receives the message and records the traffic volume consumed at each rate changeover point,

150K at the rate of 20K/yuan, 40K at the rate of 10K/yuan, and calculates the new allocable

traffic 275K, which is accumulated to 250K.

k) Since the remaining traffic volume may be not enough for the next allocation, PPS requests a

new fund quota from SCP.

l) Repeat the previous process. After converting the fund requested by SCP to the maximum

available traffic, the PPS detects that the available traffic is not enough for being allocated to

PPC, and requests another fund quota from SCP. If PPS fails to get the fund quota, it will not

allocate traffic quota for PPC, and PPC will end this PPS session.

m) PPC also sends the Access-Request (PPAQ(VQ=340K, UR=4)) quota request message to end

the PPS session on initiative. The quota request message carries the sub-attribute UR = 3 of

the PPS attribute PPAQ. That sub-attribute means Update-Reason is “User release”.

n) After the PPS receives the Access-Request (PPAQ) message, where the Update-Reason is

User release, the PPS will not allocate any quota for the PPC any longer. In this case, the PPS

must calculate out the sum consumed by the user, and send a charge deduction request to SCP,

and refund the remaining sum.

o) The PPS replies with an Access-Request message without carrying PPAQ to end the PPS

process.

5 Charging Principles

6.1 Charging PrePaid Packet Data Service User by Duration

When the PPS user originates a data communication call, the SCP allocates the duration quota for the PPS user according to the data communication duration.

a) The SCP finds out the charging type of the call according to the charging elements such as the

calling number.

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b) According to the preselected charging solution number, the found charging type, and the start

time of the call, the system can calculate the charges of a specific communication duration.

c) This specific communication duration is selectable from 0 second to the maximum duration.

The system finally works out the maximum call duration under the allocated balance.

d) If this call duration spans different discount time segments, the calls between different time

segments will be charged in segments.

6.2 Charging PrePaid Packet Data Service User by Traffic

When the PPS user originates a data communication call, the SCP allocates the traffic quota for the PPS user according to the data communication traffic.

a) The SCP finds out the charging type of the call according to the charging elements such as the

calling number.

b) According to the preselected charging solution number, the found charging type detected

earlier, and the start time of the call, the system can calculate the charges of a specific

communication duration.

c) This specific communication duration is selectable from 0 second to the set maximum

threshold of traffic. The system finally works out the maximum communication traffic under

the allocated balance.

d) If this call duration spans different discount time segments, the calls will be handled in two

modes depending on the rate setting:

(1) The call is charged at the rate of the start time of call, namely, ordinary traffic charging.

(2) The call is charged at the highest rate applicable in the two previous discount time segments,

namely, maximum traffic charging.

6.3 Activating/Deactivating Service of the PPS User

Activating/deactivating the packet prepaid service for the PrePaid Packet Data Service user through the billing system is free of charge.