7 Message Transfer Part (MTP) protocol requirements

09.143GPPApplication of ISDN User Part (ISUP) Version 3 for the Integrated Services Digital Network (ISDN) - Public Land Mobile Network (PLMN) signalling interfacePart 1: Protocol specificationTS

The Message Transfer Part (MTP) protocol shall conform to the requirements in ETS 300 008 [36] with the appropriate value for the Network Indicator (NI).

It is preferred that NI value 10 (national network) is used within GSM networks as in the fixed national network. Based on national agreement, any NI value may be applied on the interface between GSM networks and the fixed networks.

Annex A (informative): Considerations on teleservices

A.1 Relation between ISDN teleservices and GSM teleservices

Teleservices could be identified on the ISDN-PLMN interface in the User Teleservice Information parameter. High Layer Compatibility (HLC) information elements are passed transparently in the access transport parameter. Support of teleservices is an end-to-end aspect. However, the relationship between some ISDN teleservices and GSM teleservices are listed for information.

Table A.1: Relationship between ISDN teleservices and GSM teleservices

ISDN teleservices

GSM teleservices

Telephony

Telephony, Emergency call

Facsimile Group 2/3

Automatic facsimile group 3

Facsimile Group 4 Class 1

Not used

Teletex

Not used

Not used

Alternate speech and facsimile group 3

Not used

SMS, Point-To-Point, Mobile Originated

Not used

SMS, Point-To-Point, Mobile Terminated

Not used

SMS Cell Broadcast

Videotex

Not used

Telex

Not used

Message Handler System

Not used

Videotelephony

Not used

Videoconferencing

Not used

Annex B (informative): Considerations on bearer services

The mapping between parameters in the GSM call set up request message and the ISDN call set up request message is described in ETS 300 601 to ETS 300 604 ([31] to [34]).

Annex C (informative): Mapping of parameters between ISUP and MAP

Mapping of parameters between ISUP and MAP will take place for Mobile terminating calls where the MSC (acting as gateway MSC) has to interrogate the home location register in order to obtain routing information (the HLR needs to retrieve the routing information from the VLR). The interface between MSC and VLR is an internal interface, mapping of parameters on this interface are not described in this specification.

C.1 Mapping of parameters from IAM to MAP_SEND_ROUTING_INFORMATION req.

Table C.1: Mapping of parameters from IAM to MAP_SEND_ROUTING_INFORMATION req.

IAM

MAP_SEND_ROUTING_INFORMATION req.

Called Party Number

MSISDN

Closed user group interlock code

CUG Interlock

Optional forward call indicators

– Closed user group indicator

CUG Outgoing Access

Redirection information

– Redirection counter

Number of Forwarding

Access Transport/User Service Information

Network signal information

NOTE: Mapping of Network signal information is described in ETS 300 599 [35].

C.2 Mapping of parameters from MAP_SEND_ROUTING_INFORMATION rsp. to IAM

Table C.2: Mapping of parameters from MAP_SEND_ROUTING_INFORMATION rsp. to IAM

MAP_SEND_ROUTING_INFORMATION rsp.

IAM

CUG Interlock

Closed user group interlock code

CUG Outgoing Access

Optional forward call indicators

– Closed user group indicator

MSRN (note 1)

Called Party Number
(if no call forwarding is performed)

Forwarding Data (note 2)

– ForwardedToNumber

– ForwardedToSubaddress

– ForwardingOptions

notification to forwarding party

forwarding reason

Called Party Number

Access Transport

– Called Party Subaddress

Redirection information

NOTE 1: This parameter will not be present if the parameter Forwarding Data is returned.

NOTE 2: This parameter will not be present if the MSRN is returned.

Annex D (informative): Formats and codes

D.1 Unrecognised messages and parameters

The receipt of unrecognised messages and parameters shall be handled using standard message and parameter compatability rules defined in DEN/SPS-0103-1 [1].

D.2 Exceptions and clarifications to clause 3 of ITU‑T Recommendation Q.763 as modified by EN 300 356‑1

Table D.3: Exceptions and clarifications to clause 3 of ITU‑T Recommendation
Q.763 [22] as modified by EN 300 356‑1 [1]

Q.763 [22]
clause

Title

Remarks

3.5

Backward call indicators

Bit M: terminating PLMN subscribers shall be considered as ISDN terminations (this is the preferred situation, but other coding may be agreed between the PLMN and ISDN operators).

3.12

Cause indicator

For the coding of the location field, the exchanges at the interface between the mobile and fixed ISDN networks need not to be considered as an international interface.

The appropriate support of cause 20 within the originating network (e.g. provision of an announcement) is a matter of the network provider.

3.23

Forward call indicators

Bit A: the ISDN-PLMN interface can be an interface within the national network, and then the national/international indicator shall be passed on transparently on this interface. It is assumed that the national/international indicator has been set to:
1 = "call to be treated as an international call"
for incoming international calls in an international gateway exchange in the fixed or mobile network, and that otherwise it is coded:
0 = "call to be treated as a national call".

Bit I: originating PLMN subscribers shall be considered as ISDN terminations (this is the preferred situation, but other codings may be agreed between the PLMN and ISDN operators).

3.45

Redirection information

The redirection counter is incremented when the call is forwarded, however the mechanism for the allocation of a Mobile Station Roaming Number (MSRN) shall not be considered as an instance of call forwarding.

Annex E (informative): Examples of echo control procedures

E.1 Outgoing call in a Mobile-service Switching Centre (MSC)

If the requested bearer is "speech" or "3,1 kHz", the echo control device indicator is set to "1" (outgoing included) in the IAM sent by the MSC.

An incoming half echo control device is "reserved" on the outgoing circuit of the MSC.

If the backward call indicators parameter received in the ACM indicates that an incoming half echo control device is included, the "reserved" incoming half echo control device of the outgoing circuit of the MSC is disabled.

If the backward call indicators parameter received in the ACM indicates that an incoming half echo control device is not included, the "reserved" incoming half echo control device of the outgoing circuit of the MSC is enabled.

If the requested bearer is "64 kbit/s unrestricted", the echo control device indicator is set to "0" (outgoing not included). No echo devices are reserved.

E.2 Incoming call in the MSC

1) If the nature of the connection indicators parameter indicates that an outgoing half echo control device is included, any outgoing half echo control device on the incoming circuit of the MSC is disabled.

If the MSC is a Visited Mobile-service Switching Centre (VMSC), the backward call indicators parameter sent in the ACM indicates that an incoming half echo control device is enabled.

If the MSC is a Gateway Mobile-service Switching Centre (GMSC) or in case of call forwarding, the incoming half echo control device of the outgoing circuit is "reserved" and the echo control device indicator sent in the IAM is passed on:

– if the backward call indicators parameter received in the ACM indicates that an incoming half echo control device is included the incoming half echo control device of the outgoing circuit of the MSC is disabled;

– if the backward call indicators parameter received in the ACM indicates that an incoming half echo control device is not included the incoming half echo control device of the MSC is enabled. The backward call indicators in ACM are changed accordingly.

2) If the nature of the connection indicators parameter indicates that an outgoing half echo control device is not included, the outgoing half echo control device on the incoming circuit of the MSC is reserved.

If the MSC is a VMSC, the outgoing half echo control device is enabled and the backward call indicators parameter sent in the ACM indicates that an incoming half echo control device is included.

If the MSC is a GMSC or if the call is to be forwarded and the MSC knows that an outgoing half echo control device is necessary (e.g. called MS, forwarding to an international destination):

– the outgoing half echo control device on the incoming circuit is enabled and the echo control parameter sent in the IAM indicates "outgoing half echo control device included";

– the incoming half echo control device of the outgoing circuit is "reserved";

– if the backward call indicators parameter received in the ACM indicates that an incoming half echo control device is included the incoming half echo control device of the outgoing circuit of the MSC is disabled. The backward call indicators in ACM are passed on unchanged;

– if the backward call indicators parameter received in the ACM indicates that an incoming half echo control device is not included the incoming half echo control device of the MSC is enabled. The backward call indicators in ACM are changed accordingly.

If the MSC is a GMSC or if the call is to be forwarded and the MSC knows that an outgoing half echo control device is not necessary:

– the outgoing half echo control device on the incoming circuit is disabled and the echo control parameter in the IAM is passed on;

– the incoming half echo control device on the outgoing circuit is disabled.

E.3 Examples of echo control procedure

The following additional notations are used in figures E.1 to E.13:

G Gateway in the fixed network

(o.i) outgoing half echo control device included

(o.ni) outgoing half echo control device not included

(i.i) incoming half echo control device included

(i.ni) incoming half echo control device not included

(*) echo control device "reserved"

* echo control device enabled

x echo control device disabled

i incoming half echo control device

o outgoing half echo control device

E.3.1 Call from a mobile station to a mobile station via the fixed network

Figure E.1

E.3.2 Call from a mobile station to fixed network with no echo control device

Figure E.2

E.3.3 Call from a mobile station to fixed network with echo control device

Figure E.3

E.3.4 Call from fixed network with no echo control device to a mobile station roaming in a PLMN of another country

Figure E.4

E.3.5 Call from fixed network with echo control device to a mobile station roaming in a PLMN of another country

Figure E.5

E.3.6 Call from fixed network with no echo control device to a mobile station

Figure E.6

E.3.7 Call from fixed network with echo control device to a mobile station

Figure E.7

E.3.8 Call forwarded by the VMSC

Figure E.8

E.3.9 Call forwarded by the VMSC to the fixed network with no echo control device

Figure E.9

E.3.10 Call with no outgoing echo control device included in a preceding exchange forwarded by the VMSC to the fixed network with no echo control device in the terminating network. The VMSC knows that an outgoing half echo control device is not necessary

Figure E.10

E.3.11 Call with no outgoing echo control device included in a preceding exchange forwarded by the VMSC to the fixed network with echo control device in the terminating network. The VMSC knows that an outgoing half echo control device is not necessary

Figure E.11

E.3.12 Call with no outgoing echo control device included in a preceding exchange forwarded by the VMSC to the fixed network with no echo control device in the terminating network. The VMSC knows that an outgoing half echo control device is necessary

Figure E.12

E.3.13 Call with no outgoing echo control device included in a preceding exchange forwarded by the VMSC to the fixed network with echo control device in the terminating network. The VMSC knows that an outgoing half echo control device is necessary

Figure E.13