Interworking between CAMEL SM and IN SM

IN Short Message Service (feature 910) has a proprietary functionality which is similar to the SMS part of CAMEL 3 and CAMEL 4. For more details, see IN

When the subscriber is roaming, CAMEL 3 CAMEL 4 are the features that can be active. When the subscriber is in the Home PLMN, the following case cases can be distinguished:

. _{If the IN functionality MO DP is set for the subscriber, the IN MO} functionality takes precedence over CAMEL 3. If you want CAMEL 3 to work for that subscriber also in the HPLMN, you have to set off Feature 910: IN Short Message Service MO DP for that subscriber.

. _{When IN functionality MT DP is set for the subscriber, IN MT}

functionality will take precedence over CAMEL 4. If you want CAMEL 4 to work for that subscriber also in the HPLMN, you have to set offFeature 910: IN Short Message Service MT DP for that subscriber.

1.15

Short message routing

Most of the operators have GSM network with more than one SMSC. This means that services offered by one SMSC are not the same as those offered by another SMSC.

For example, one SMSC can be dedicated for MO-MTs and voice mail alert services, and another for e-mail, telefax, and for accessing service provider services (such as weather, stock market information), and so on. This is confusing for the subscribers, because if they want to use all the services, they should not only know many SMSC addresses, but also remember to change the address in the MS before using the services.

A solution for overcoming this is to always use the same SMSC address in the MS, and to configure the VMSC in a way that the MO-SM is routed to the right SMSC in the PLMN. This is possible only if the MSC is able to solve the destination application from the MO-SM. The standard procedure for this is to use a PID (Protocol Identifier).

The MML command for creating SMS routing analysis is CFE . For example, when sending an MO-SM, the subscriber selects the appropriate PID value (for example, telefax, X.400), after which the MSC should know in which SMSC the application exists.

Figure 31. SMS routing

However, the PID alone is not enough, because there are applications which do not have PID values of their own.

In the Nokia VMSC you can solve this by using a Service Application Prefix (SAP). The Nokia SMSC also uses this prefix to differentiate between the applications. Each application known by the SMSC has its own SAP. The SAP can be, for example, 991 for service provider applications, 992 for e-mail, 993 for telefax and so on. Note that in this way it is not necessary to change the PID value for e-mail or telefax. The subscriber gives the SAP in the beginning of the destination address, for example, weather reports could be requested by sending a message to address '991 1000'. In this case, 991 indicates the service provider application, and 1000 the service (here: weather reports).

There is a table for MO-SM routing based on PIDs and/or SAPsin the MSC, and an MML for maintaining the table, as shown in the example below:

SMSC2 for fax and email

messages VMSC fax MO-SMS SMS-IWMSC2 1 SMS-IWMSC1 SMSC1 for MS-to-MS messages fax MO-SMS 2 1 normal MO-SMS 1 2 2

Table 8. Example of a routing table Service

Application Name

PID SAP SAPTYPE SMSC

address

Tariff class

CIMD  991 international 443580002 1

FAX 52 993 national 443580001 3

E-MAIL 53 EMAIL alphanumeric 443580001 4

E-MAIL  992 international 443580001 

MT 0   443580003 

DEFAULT    443589999 2

The fields of the table are interpreted in the following way:

1. If a PID in the MO-SM has been defined in the table, use the SMSC address defined for the PID.

2. If a SAP in the MO-SM has been defined in the table, use the SMSC address defined for the SAP.

3. You can also set a default SMSC to be used and/or a tariff class for it in a case where no SAP or PID analysis is found. This could be used, for example, to make all the subscribers of a particular network use the operator's own SMSCs. If none of the above have been defined, use the SMSC address normally given by the subscriber.

If, for example, a PID is defined for fax only, the normal SMS functionality is not affected. Only faxes are handled in a different way, everything else is handled as if no PID/SAP analysis existed.

When routing SMs from one MSC to another, you must be careful that a loop between MSCs does not occur. This could happen when the MSC1 routes messages to MSC2 which again forwards them to the MSC1.

For more information on the relation of tariff classes and charging, see Charging

One consequence of SMS routing is that when the SMSCs send MT-SMs, they all use individual SMSC addresses. However, they correspond to one logical SMSC address. This can cause problems with an MS if, when receiving status reports, it compares this MT-SMS address with the original address stored in mobile setup. This can be solved by configuring the SMSC address used towards subscribers in the SMS-GMSC . The same address that SMSC originally used in MT-SMS when setting the MWD must be used to make sure that alerts work correctly, that is, they are sent from the HLR to the correct SMSC.

For more information see SMS management instructions in Configuring network

elements for SMS , and Managing SMS network element-specific data . See also Working examples for SMS management .

The following figure describes how SMSC address are used in MT-SMS between different network elements:

Figure 32. SMSC address used in MT-SMS between different network elements

SMS routing analysis

The decision whether the SMS routing analysis is executed or not in the VMSC, depends on the availability ofFeature 1165: GSM Phase 2+ Enhancements . The execution of the analysis in the SMS-IWMSC is unconditional if you have this function in use.

If you have feature 1165 in use in your network, the SMSC address is analysed by invoking the SMS routing support analysis. This analysis indicates whether the SMS routing analysis should be executed or not.

Linetype means SMS transfer from SMSCA Linetype means SMS transfer from SMSCB

SMSCB SMSCA SMSCB SMSCA SMSC SMSC SMSC A SMSC B SMS-GMSC HLR VMSC

If you do not have feature 1165 in use, the decision about executing the SMS routing analysis is entirely based on the roaming status information received form the VLR. The roaming status is determined from the IMSI of the subscriber in the VLR. If the roaming status is home network/home subscriber, the SMS routing analysis is invoked.

Note

If the SMS routing support analysis function is not active, the VLR sets the subscriber's roaming status by reading the status of HPLMN and home country (HCOUN) from the result record in the PLMN-specific parameter file and sends it to the SMS application. If you set the home PLMNs in the PLMN-specific parameter file with the MXN command so that HPLMN=Y, HCOUN=Y, the roaming status will be 'HOME' despite the different network codes. This way the SMS routing analysis is executed for all home subscribers.

For further information, see Alphanumeric addressing of SMS-related

applications .