3gpp Charging characteristics

Charging Characteristics can be supplied by the HLR/HSS to the SGSN/MME as part of the subscription information. A subscriber may have charging characteristics assigned to his subscription and/or his subscribed APNs. The SGSN applies a pre‑configured default if no charging characteristics are supplied by the HLR/HSS. The SGSN shall support three different charging characteristics default configurations:

Charging characteristics in SGSN

·       the home default behaviour for subscribers of the SGSN's PLMN;

·       the visiting default behaviour for visitors using a P-GW belonging to the same PLMN as the SGSN;

·       the roaming default behaviour for visitors using a P-GW belonging to their home PLMN.

The SGSN can determine the P-GW PLMN from the operator identifier part of the APN. Optionally the SGSN may support several visiting and roaming default behaviours based on the MNC/MCC combination of the subscriber.

In the case of a home subscriber, the charging characteristics are selected by the SGSN according to the following procedures. For IP CAN bearer specific charging characteristics (i.e. those used for the S-CDRs that are generated for this IP CAN bearer):

·      If the MS requests a particular APN then:

*    If the SGSN accepts this request (i.e. it has been verified against the subscription) then:

§       If it has been matched against the wildcard APN then:

-     If charging characteristics for the wildcard APN are present in the subscription information then they shall be used;

-     If no charging characteristics are present for the wildcard APN but subscription related charging characteristics are present, then they shall be chosen;

-     If neither of the two are present then the SGSN home default shall be applied.

§       If it has been matched against a specific subscribed APN then:

-     If charging characteristics for this APN are present in the subscription information then they shall be used;

-     If no charging characteristics are present for the APN but subscription related charging characteristics are present, then they shall be chosen;

-     If neither of the two are present then the SGSN home default shall be applied.

*    If the SGSN rejects the request then charging characteristics selection does not apply.

·       If the MS does not request an APN then:

*    If the SGSN chooses a subscribed APN then:

§       If charging characteristics for this APN are present in the subscription information then they shall be used;

§       If no charging characteristics are present for the APN but subscription related charging characteristics are present, then they shall be chosen;

§       If neither of the two are present then the SGSN home default shall be applied.

*    If only the wildcard APN is present in the subscription, i.e. the SGSN applies its configured default APN then:

§       If charging characteristics for the wildcard APN are present in the subscription information then they shall be used;

§       If no charging characteristics are present for the wildcard APN but subscription related charging characteristics are present, then they shall be chosen;

§       If neither of the two are present then the SGSN home default shall be applied.

For the non-IP CAN bearer specific CDR types, i.e. the M-CDRs and the SMS CDRs, the SGSN applies the subscription specific charging characteristics, or, if not supplied, it shall choose the home default behaviour as defined above.

In case of subscribers from other PLMNs, the SGSN may be configured to either apply the "home subscriber case" charging characteristics selection procedure defined above, or to ignore charging characteristics provided by the subscriber's HLR, and apply a default configuration instead. If default charging characteristics are selected for the foreign subscriber, then the SGSN shall choose either the visiting or roaming default behaviour for the IP CAN bearer specific charging characteristics, according to the roaming or visiting scenario, as described above. For M-CDRs and SMS CDRs, the operator can configure if the roaming or the visiting behaviour shall be applied, since no P-GW is involved.

Upon activation of a IP CAN bearer, the SGSN forwards the charging characteristics to the P-GW according to the following rules:

·       if charging characteristics were received from the HLR/HSS, then they shall be sent as provided by the HLR/HSS, regardless of the home, visiting, or roaming case, and regardless of whether the SGSN applies the HLR/HSS supplied charging characteristics or chooses to ignore them;

·       if no charging characteristics were received from the HLR/HSS, then the SGSN does not forward any charging characteristics to the P-GW.

Upon activation of a IP CAN bearer, the S4-SGSN forwards the charging characteristics to the S-GW according to the following rules:

·       if charging characteristics were received from the HLR/HSS, then they shall be sent as provided by the HLR/HSS, regardless of the home, visiting, or roaming case, according to the following rules:

o        if charging characteristics for APN are present in the subscription information they shall be forwarded;

o        if no charging characteristics are present for the APN but subscription related charging characteristics is present, they shall be forwarded.

·       if no charging characteristics were received from the HLR/HSS, then the S4-SGSN does not forward any charging characteristics to the S-GW.

Charging characteristics in MME

The MME does not utilize charging characteristics as it does not generate charging information.

Upon activation of a IP CAN  session, the MME forwards the charging characteristics to the S-GW according to the following rules:

·       if charging characteristics were received from the HLR/HSS, then they shall be sent as provided by the HLR/HSS, regardless of the home, visiting, or roaming case according to the following rules:

§         if charging characteristics for the PDN connection (e.g APN) is present in the subscription information it shall be forwarded;

§         if no charging characteristics is present for the PDN connection (e.g APN) but subscription related charging characteristics is present, it shall be forwarded.

·       if no charging characteristics were received from the HLR/HSS, then the MME does not forward any charging characteristics to the S-GW.

 

 

 

 

Charging characteristics in S-GW

The S-GW shall apply charging characteristics to its IP CAN bearers. It shall either apply the S4-SGSN/MME supplied parameters, or it may be configured to ignore the S4-SGSN/MME supplied charging characteristics in any combination of the following cases:

·       visiting case, i.e. the P-GW belongs to same PLMN the subscriber belongs to a different PLMN;

·       roaming case, i.e. the P-GW belongs to a different PLMN;

·       home case, i.e. the subscriber belongs to the same PLMN as the S-GW and P-GW; or

·       unconditionally, i.e. it always ignores the S4-SGSN/MME supplied parameters.

If the S-GW ignores the parameters supplied by the S4-SGSN/MME, it shall nevertheless accept the IP CAN session request. It shall then apply its own pre‑configured charging characteristics as appropriate, i.e. the home, visiting or roamingbehaviour. The S-GW shall support the configuration of one set of default charging characteristics (i.e. home, visiting, roaming).

Upon activation of a IP CAN session, the S-GW forwards the charging characteristics to the P-GW according to the following rules:

·       if charging characteristics were received from the S4-SGSN/MME, then they shall be sent as provided by the S4-SGSN/MME, regardless of the home or visiting case;

·       if no charging characteristics were received from the S4-SGSN/MME, then the S-GW does not forward any charging characteristics to the P-GW.

Charging characteristics in P-GW

The P-GW shall apply charging characteristics to its IP CAN bearers. It shall either apply the SGSN/S-GW supplied parameters, or it may be configured to ignore the SGSN/S-GW supplied charging characteristics in any combination of the following cases:

·       visiting case, i.e. the subscriber belongs to a different PLMN;

·       roaming case, i.e. the subscriber belongs to same PLMN and the SGSN/S-GW belongs to a different PLMN;

·       home case, i.e. the subscriber belongs to the same PLMN as the SGSN/S-GW and P-GW; or

·       unconditionally, i.e. it always ignores the SGSN/S-GW supplied parameters.

If the P-GW ignores the parameters supplied by the SGSN/S-GW, it shall nevertheless accept the IP CAN session request. It shall then apply its own pre‑configured charging characteristics as appropriate, i.e. the home, visiting or roaming behaviour. The P-GW shall support the configuration of one set of default charging characteristics (i.e. home, visiting, roaming) for each of its supported APNs.

Charging characteristics generally

Charging Characteristics consists of a string of 16 bits designated as Behaviours (B), freely defined by Operators, as shown in 3GPP TS 32.298 [41].

For example, one way to define a behaviour, could be to associate it to a specific usage designed according to following guidances:

One usage may consist of a set of trigger profiles associated to CDR types, with following trigger sets, e.g.:

·       S-CDR: activate/deactivate CDRs, time limit, volume limit, maximum number of charging conditions, tariff times;

·       SGW-CDR: same as S-CDR, plus maximum number of SGSN/MME changes;

·       PGW-CDR: same as S-CDR, plus maximum number of S-GW changes;

·       M-CDR: activate/deactivate CDRs, time limit, and maximum number of mobility changes;

·       SMS-MO-CDR: activate/deactivate CDRs;

·       SMS-MT-CDR: active/deactivate CDRs.

·       LCS-MO-CDR.

·       LCS-MT-CDR.

·       LCS-NI-CDR.

In addition to these trigger sets, an optional charging gateway address may also be specified:

-     If the CGF address is configured in the P-GW’s selected charging characteristics behaviour, the P-GW shall apply it for the PGW-CDRs. P-GW applied CGF address is sent to SGSN/S-GW during IP CAN bearer activation.

• - In the home or visiting case, the S-GW shall apply from P-GW received CGF address to the SGW-CDRs pertaining to this IP CAN bearer. In the roaming case, or if no CGF address is received from the P-GW, the S-GW shall use the CGF address from its own applied charging characteristics behaviour, or, if it does not exist, it uses the default CGF address. There is no need to send CGF address to S4-SGSN/MME as it does not generate charging data.

-     In the home or visiting case, the SGSN shall apply the received CGF address to the S-CDRs pertaining to this IP-CAN bearer. In the roaming case, or if no CGF address is received from the P-GW, then the SGSN shall use the CGF address from its own selected charging characteristics behaviour, or, if it does not exist, use the default CGF address. For M-CDRs and SMS CDRs, the SGSN shall use the CGF address configured in the charging characteristics behaviour that it applies to the respective CDRs, or if no such address is configured then the default CGF shall be used.

Table A.1, A.2 and A.3 are informative examples intended for clarification.

Table A.1: Example of charging characteristics behaviours for SGSN

		S-CDR					M-CDR
Behaviour Index bits 0 - 3	CGF Address	Active	Time limit	Volume limit	Change cond	Tariff times	Active	…
0	-	Yes	30 min	100 K	2	0-7, 7-12, …	Yes	..
1	100.128.35.20	No	-	-	-	-	No	..
2	-	Yes	10 min	50 K	1	0-24	Yes	..
..	..	..	..	..	..	..	..	..

 

Charging characteristics behaviour in S-GW is used for SGW-CDR generation

Table A.2: Example of charging characteristics behaviours for S-GW

 

		SGW-CDR
	Behaviour Index Bits 0-15		Primary and Secondary CGF Addresses	Active	Time Limit	Vol Limit	Change Cond.	Tariff times	…
	0		100.128.35.20 100.128.35.21	Yes	30 min	100K	2	0-7, 7-12	...
	1		100.128.35.21 100.128.35.20	No	-	-	-	-	…
	2		100.128.35.21 100.128.35.20	Yes	10 min	50K	1	0-24	...
	…		…	…	…	…	…	…	…

 

Charging characteristics behaviour in P-GW is used for PGW-CDR generation / and for online charging.

FBC is always active in P-GW. PCRF may provide default charging method to PCEF (P-GW) per IP CAN bearer session. If received by the PCEF, it supersedes the ‘Default charging method’ in charging characteristics behaviour, see TS 23.203 [72] for more information about default charging method. PCRF may also provide CGF/OCS addresses to P-GW per IP CAN bearer session. If received by the P-GW it supersedes the ‘Primary CGF/OCS address’ and ‘Secondary CGF/OCS address’ in charging characteristics behaviour, see TS 23.203 [72] for more information. 

Table A.2: Example of charging characteristics behaviours for P-GW

		Offline charging (PGW-CDR)							Online charging
Behaviour Index Bits 0-15	Default charging method	Primary and Secondary CGF addresses	Active	Time Limit	Vol Limit	Change Cond.	Tariff times	…	Primary and Secondary OCS addresses	Active	…
0	Online	100.128.35.20 100.128.35.21	Yes	30 min	100K	2	0-7, 7-12	...	100.128.35.30 100.128.35.31	Yes	…
1	Offline	100.128.35.21 100.128.35.20	No	-	-	-	-	…	-	No	…
2	Online /Offline	100.128.35.21 100.128.35.20	Yes	10 min	50K	1	0-24	...	100.128.35.31 100.128.35.30	Yes	…
…	…	…	…	…	…	…	…	…	…	…	…

 

Other examples for behaviours are:

·       Selection of the applicable idle context purge timer, i.e. use global value or use special value. This feature could be used to distinguish between customers and/or APNs whose IP CAN bearers should be purged after short (e.g. 30 minutes) or long (e.g. 12 hours) periods of inactivity.

·       Use specific charging gateway address (override all other configured/selected CG addresses).

·       Deactivate SMS-MO-CDRs for customers of the own PLMN using pre-configured SMSC addresses.

·       Disable PGW-CDRs for roamers that use the HPLMN P-GW.

·       Allow or inhibit the use of own P-GWs by visitors.

·       Allow or inhibit network triggered QoS change (upgrade and/or downgrade).

The SGSN selects the charging characteristics behaviour for M-CDR generation upon the creation of a MM context. SGSN, S-GW and P-GW select the charging characteristics behaviour upon creation of a IP CAN bearer. Once selected, the charging characteristics behaviour shall be maintained throughout the lifetime of the MM or IP CAN bearer. If the SGSN receives modified subscriber information from the HLR/HSS (e.g. execution of a stand-alone Insert Subscriber Data procedure) which includes changes the charging characteristics, the new charging characteristics shall be applied only to new IP CAN bearers. This implies the following:

-     the S4-SGSN/MME shall not send IP CAN bearer modifications for the existing IP CAN bearer to the S-GW because of charging characteristics change;

-     the SGSN shall not send IP CAN bearer modifications for the existing IP CAN bearer to the P-GW because of charging characteristics change.