10 Contents of messages
23.0793GPPRelease 17Support of Optimal Routeing (SOR)Technical realizationTS
This clause specifies the changes to the content of each message shown in clauses 5, 6 and 9, including those messages which are already specified for UMTS but which require changes for Optimal Routeing. It should be read as a ‘delta’ on the corresponding clause of 3GPP TS 23.018 [6]; those information elements which are the same for SOR as for the basic call without OR are not specified in this clause.
In the tables which follow, information elements are shown as mandatory (M) or conditional (C). A mandatory information element shall always be present. A conditional information element shall be present if certain conditions are fulfilled; if those conditions are not fulfilled it shall be absent.
10.1 Messages on the B interface (MSC-VLR)
10.1.1 Send Info For Outgoing Call
This message is specified in 3GPP TS 23.018 [6].
10.1.2 Send Info For Outgoing Call negative response
This message is specified in 3GPP TS 23.018 [6].
10.1.3 Send Info For Incoming Call
This message is specified in 3GPP TS 23.018 [6].
10.1.4 Send Info For Incoming Call ack
This message is specified in 3GPP TS 23.018 [6]. The following additional information elements are required:
|
Information element name |
Required |
Description |
|
OR indicator |
C |
Indicates whether the call has been routed directly from a GMSC not in the same PLMN as the HLR. Shall be present if it was received in the Provide Roaming Number, otherwise shall be absent. |
|
GMSC address |
C |
E.164 address of the GMSC. Shall be present if it was received in the Provide Roaming Number, otherwise shall be absent. |
|
Call reference number |
C |
Call reference number used by the GMSC for this call. Shall be present if it was received in the Provide Roaming Number, otherwise shall be absent. |
|
OR not supported in GMSC |
C |
Indicates that the GMSC does not support Optimal Routeing. Shall be present if it was received in the Provide Roaming Number, otherwise shall be absent. |
10.1.5 Send Info For Incoming Call negative response
This message is specified in 3GPP TS 23.018 [6].
10.1.6 Complete Call
This message is specified in 3GPP TS 23.018 [6]. The following additional information elements are required:
|
Information element name |
Required |
Description |
|
OR indicator |
C |
Indicates whether the call has been routed directly from a GMSC not in the same PLMN as the HLR. Shall be present if it was received in the Provide Roaming Number, otherwise shall be absent. |
|
GMSC address |
C |
E.164 address of the GMSC. Shall be present if it was received in the Provide Roaming Number, otherwise shall be absent. |
10.1.7 Process Call Waiting
This message is specified in 3GPP TS 23.018 [6]. The following additional information elements are required:
|
Information element name |
Required |
Description |
|
OR indicator |
C |
Indicates whether the call has been routed directly from a GMSC not in the same PLMN as the HLR. Shall be present if it was received in the Provide Roaming Number, otherwise shall be absent. |
|
GMSC address |
C |
E.164 address of the GMSC. Shall be present if it was received in the Provide Roaming Number, otherwise shall be absent. |
10.2 Messages on the C interface (MSC-HLR)
10.2.1 Send Routeing Info
This message is specified in 3GPP TS 23.018 [6]. The following additional information elements are required:
|
Information element name |
Required |
Description |
|
Interrogation type |
M |
Indicates the type of interrogation: basic(for routeing information for an MT call) or forwarding (when the GMSC has been asked to resume call handling for OR of late call forwarding). |
|
OR interrogation indicator |
C |
Indicates that the interrogation is from a GMSC not in the same PLMN as the HLR. Shall be present if the interrogation is from a GMSC not in the same PLMN as the HLR, otherwise shall be absent. |
|
OR capability |
C |
Indicates the phase of OR which the GMSC supports. Shall be present if the GMSC supports OR, otherwise shall be absent. |
|
GMSC or gsmSCF address |
M |
E.164 address of the GMSC. |
|
Call reference number |
C |
Call reference number used by the GMSC for this call. Shall be present if the interrogation type=basic call, otherwise shall be absent. |
|
Forwarding reason |
C |
Indicates the reason for forwarding (on busy, on no subscriber reply, or on mobile subscriber not reachable). Shall be present if the Interrogation type=forwarding, otherwise shall be absent. |
|
Basic service group |
C |
Basic service group which applies for this call. Shall be present if the Interrogation type=forwarding, otherwise shall be absent. |
|
Basic service group 2 |
C |
Basic service group which applies for this call. Shall be present if the Interrogation type=forwarding and if the VMSC has determined that the forwarded call is to be treated as a SCUDIF call in accordance with the rules in 3GPP TS 23.172[10], otherwise shall be absent. |
10.2.2 Send Routeing Info ack
This message is specified in 3GPP TS 23.018 [6]. Two new information elements are required, and the condition for the presence of one existing information element is changed, as shown in the following table.
|
Information element name |
Required |
Description |
|
Forwarding interrogation required |
C |
Indicates that the GMSC shall interrogate the HLR for routeing information for late call forwarding. Shall be present if the SRI ack contains an MSRN and GMSC has to interrogate the HLR for routeing information for late call forwarding, otherwise shall be absent. |
|
VMSC address |
C |
E.164 address of the VMSC in whose area the B subscriber is currently registered. Shall be present in the Send Routeing Info ack if the OR interrogation indicator in the Send Routeing Info was present and the HLR supports optimal routeing of basic mobile-to-mobile calls and the HLR has not determined that the call is to be forwarded, otherwise shall be absent. |
|
Roaming number |
C |
E.164 address required to route the call to the VMSC of the B party. Shall be present in the Send Routeing Info ack which is sent in response to a Send Routeing Info with Interrogation type=basic if the HLR has determined that the charging requirements for optimal routeing are not contravened and that the call is not to be forwarded, otherwise shall be absent. |
10.2.3 Send Routeing Info negative response
This message is specified in 3GPP TS 23.018 [6]. The negative response information element can take the following values in addition to those specified in 3GPP TS 23.018 [6]:
– OR not allowed.
– Busy subscriber.
– No subscriber reply.
10.3 Messages on the D interface (VLR-HLR)
10.3.1 Provide Roaming Number
This message is specified in 3GPP TS 23.018 [6]. The following additional information elements are required:
|
Information element name |
Required |
Description |
|
GMSC address |
C |
E.164 address of the GMSC. Shall be present if it was received by the HLR in the Send Routeing Info, otherwise shall be absent. |
|
Call reference number |
C |
Call reference number used by the GMSC for this call. Shall be present if it was received by the HLR in the Send Routeing Info, otherwise shall be absent. |
|
OR interrogation indicator |
C |
Indicates that the HLR received the corresponding Send Routeing Info from a GMSC not in the same PLMN as the HLR. Shall be present if the HLR received the Send Routeing Info from a GMSC not in the same PLMN as the HLR, otherwise shall be absent. |
|
OR not supported in GMSC |
C |
Indicates that the GMSC does not support OR, and that RCH shall not be sent for optimal routing. Shall be present if the HLR received the Send Routeing Info from the GMSC without the OR-capability information Element, otherwise it shall be absent. |
10.3.2 Provide Roaming Number ack
This message is specified in 3GPP TS 23.018 [6].
10.3.3 Provide Roaming Number negative response
This message is specified in 3GPP TS 23.018 [6].
10.3.4 Provide Subscriber Information
This message is specified in 3GPP TS 23.018 [6].
10.3.5 Provide Subscriber Information ack
This message is specified in 3GPP TS 23.018 [6].
10.4 Messages on the E interface (MSC-MSC)
10.4.1 Resume Call Handling
The following information elements are required:
|
Information element name |
Required |
Description |
|
Call reference number |
M |
Call reference number used by the GMSC for this call. |
|
Forwarding reason |
C |
Indicates the reason for forwarding (on call deflection, on busy, on no subscriber reply, or on mobile subscriber not reachable). Shall be present if the call is forwarded other than for the MT roaming retry reason. |
|
Basic service group |
M |
Basic service group which applies for this call. For SCUDIF calls, see 3GPP TS 23.172 [10] for the use of this information element. |
|
IMSI |
M |
IMSI of the B subscriber. |
|
Forwarded-to number |
C |
E.164 number of the C subscriber. Shall be present if the call is forwarded other than for the MT roaming retry reason. |
|
Notification to calling party |
C |
Indication of whether the calling party is to be notified that the call has been forwarded. Shall be present if the call is forwarded other than for MT roaming retry reason. |
|
Forwarded-to subaddress |
C |
Subaddress of the C subscriber (see 3GPP TS 23.003 [5]). Shall be present if a forwarded-to subaddress is stored in the VLR in association with the forwarded-to number; otherwise shall be absent. |
|
Redirecting presentation |
C |
Indication of whether the MSISDN of the B subscriber shall be presented to the C subscriber. Shall be present if VMSCB supports the handling of the redirecting number, otherwise shall be absent. |
|
MSISDN |
C |
E.164 number which identifies the B subscriber. It will be used to create the redirecting number presented to the C subscriber. Shall be present if VMSCB supports the handling of the redirecting number, otherwise shall be absent. |
|
CUG interlock |
C |
For the definition of this IE, see 3GPP TS 23.085 [8]. Shall be present if the VLR has determined that the forwarded call is to be treated as a CUG call in accordance with the rules in 3GPP TS 23.085 [8], otherwise shall be absent. |
|
CUG outgoing access |
C |
For the definition of this IE, see 3GPP TS 23.085 [8]. Shall be present if the VLR has determined that the forwarded call is to be treated as a CUG call with outgoing access in accordance with the rules in 3GPP TS 23.085 [8], otherwise shall be absent. |
|
Basic service group 2 |
C |
For the definition of this IE, see 3GPP TS 23.172 [10]. Shall be present if the VMSC has determined that the forwarded call is to be treated as a SCUDIF call in accordance with the rules in 3GPP TS 23.172[10], otherwise shall be absent. |
|
MT Roaming Retry |
C |
Indication that the call is forwarded for MT roaming retry. All other forwarding parameters are not relevant if this IE is present. |
10.4.2 Resume Call Handling ack
This message contains no information elements.
10.4.3 Resume Call Handling negative response
The negative response information element can take the following values:
– OR not allowed.
– Forwarding failed.
Annex A (informative):
Handling of an IAM at an MSC
An MSC which receives an IAM from an originating exchange may react in three different ways:
– It acts as a transit exchange, i.e. it relays the IAM to a destination exchange determined by analysis of the called party address, and thereafter relays other ISUP signalling between the originating and destination exchange until the connection is released. This behaviour is not specific to UMTS or GSM.
– It acts as a terminating exchange, i.e. it attempts to connect the call to an MS currently registered in the service area of the MSC.
– It acts as a GMSC, i.e. it interrogates an HLR for information to route the call. If the HLR returns routeing information, the MSC uses the routeing information from the HLR to construct an IAM, which it sends to a destination exchange determined by analysis of the routeing information from the HLR.
The method which the MSC uses to determine how to handle the IAM is described in 3GPP TS 23.018 [6]. However, the number analysis required to derive the address of an HLR in a different PLMN from the MSC is much more extensive than that required to derive the address of an HLR in the same PLMN as the MSC – the MSC needs to be able to recognise the combination of country code and national destination code for every subscriber of every PLMN to which calls are to be optimally routed. In order to avoid the need to maintain the tables required to support this extensive number analysis, and the run-time processing load of performing the number analysis, optimal routeing of mobile-to-mobile calls is handled as a mobile originating CAMEL service; the gsmSCF analyses the destination address (after possible modification of the number by other MO CAMEL services) to determine whether the call is eligible for optimal routeing. If the call is eligible for optimal routeing, the gsmSCF indicates this to VMSCA, which routes the call to an associated GMSC function, which in turn sends a request for routeing information to the appropriate HLR.
When a GMSC has interrogated an HLR and received an MSRN, the GMSC may need to route the call to the HPLMN of the called subscriber. If the call is routed through an MSC which has the capability to analyse an address to derive an HLR address, a method must be provided to prevent the transit MSC from performing a further interrogation of the HLR, using the MSRN as an MSISDN. The method used to prevent this further interrogation is a matter for the PLMN operator.
Annex B (informative):
Change history
|
Change history |
|||||||
|
Date |
Meeting |
TDoc |
CR |
Rev |
Cat |
Subject/Comment |
New version |
|
Apr 1999 |
Transferred to 3GPP CN1 |
||||||
|
CN#03 |
Approved at CN#03 |
3.0.0 |
|||||
|
CN#04 |
Notification of Call Forwarding to the gsmSCF |
3.1.0 |
|||||
|
CN#05 |
001 |
OR capability IE in PRN |
3.2.0 |
||||
|
003 |
Removal of TDP Criteria from Resume Call Handling |
3.2.0 |
|||||
|
005r1 |
Separation of success & failure cases for OR of late call forwarding |
3.2.0 |
|||||
|
006 |
Notification of Call Forwarding to the gsmSCF before activating call forwarding process |
3.2.0 |
|||||
|
007 |
Handling of Release during forwarding interrogation |
3.2.0 |
|||||
|
CN#06 |
008 |
Introduction of CAMEL Phase 3 |
3.3.0 |
||||
|
CN#07 |
009 |
Correction of CF Notification |
3.4.0 |
||||
|
010r1 |
Replacement of references to GSM with references to UMTS |
3.4.0 |
|||||
|
011 |
Indication of OR capability of the GMSC to the destination MSC/VLR |
3.4.0 |
|||||
|
CN#08 |
014 |
Indication in PRN of support of Long FTNs |
3.5.0 |
||||
|
CN#09 |
015 |
Sheet 1 of Procedure OR_HLR_CF |
3.6.0 |
||||
|
CN#11 |
Release 4 after CN#11 |
4.0.0 |
|||||
|
CN#15 |
016 |
Introduction of CAMEL Phase 4 |
5.0.0 |
||||
|
CN#16 |
019 |
Removal of unnecessary references to O-CSI |
5.1.0 |
||||
|
CN#18 |
020r1 |
Optimal routeing and CAMEL discrepancy |
5.2.0 |
||||
|
CN#18 |
024 |
Correction to figure 7a (handling of RCH in GMSC) |
5.2.0 |
||||
|
CN#21 |
025r4 |
Correction to interaction between ORLCF and forwarding notification |
5.3.0 |
||||
|
CN#21 |
026r1 |
Notification of the 2nd BSG in case of Late CF with OR |
5.3.0 |
||||
|
CN#22 |
027 |
Correction to MAP RCH – GMSC shall check Offered CAMEL4 CSIs |
5.4.0 |
||||
|
CN#24 |
080 |
Enhancement to Route_Permitted procedure to handle Short/ Long FTNs |
5.5.0 |
||||
|
CN#26 |
Release 6 after CN#26 |
6.0.0 |
|||||
|
CT#30 |
0083r2 |
Correction to relationship between the OR implemention and CAMEL |
6.1.0 |
||||
|
CT#36 |
0085 |
Mobile Termination whilst the MS is moving to another MSC |
7.0.0 |
||||
|
CT#42 |
Upgraded unchanged from Rel-7 |
8.0.0 |
|||||
|
CT#46 |
– |
Update to Rel-9 version (MCC) |
9.0.0 |
||||
|
2011-03 |
– |
Update to Rel-10 version (MCC) |
10.0.0 |
||||
|
2012-09 |
– |
Update to Rel-11 version (MCC) |
11.0.0 |
||||
|
2014-09 |
– |
Update to Rel-12 version (MCC) |
12.0.0 |
||||
|
2015-12 |
– |
Update to Rel-13 version (MCC) |
13.0.0 |
||||
|
2017-03 |
– |
Update to Rel-14 version (MCC) |
14.0.0 |
||||
|
2018-06 |
– |
Update to Rel-15 version (MCC) |
15.0.0 |
||||
|
2020-07 |
– |
Update to Rel-16 version (MCC) |
16.0.0 |
||||
|
2022-03 |
– |
– |
– |
– |
– |
Update to Rel-17 version (MCC) |
17.0.0 |