2 Message functional definitions and contents

04.803GPPMobile Radio Interface Layer 3 - Supplementary Services Specification Formats and CodingRelease 1998TS

2.1 General

This clause defines the structure of the messages of the layer 3 protocol defined in GSM 04.80. These messages are standard L3 messages as defined in GSM 04.07.

Each definition includes:

a) a brief description of the message;

b) a table listing the information elements in the order of their appearance in the message. In a sequence of consecutive IEs with half octet length, the first IE occupies bits 1 to 4 of octet N, the second bits 5 to 8 of octet N, the third bits 1 to 4 of octet N+1 etc.;

For each IE the table indicates:

1) the information element identifier, in hexadecimal notation, if the IE has format T, TV or TLV. If the IEI has half octet length, it is specified by a notation representing the IEI as a hexadecimal digit followed by a "-" (example: B-);

2) the name of the IE (which gives an idea of the semantics of the element), which is used in this and other specifications as a reference to the IE within the message;

3) the name of the type of the IE (which indicates the coding of the value part of the IE), and a reference to a description of the value part of the IE;

4) the presence requirement indication (M, C or O) for the IE, as defined in GSM 04.07;

5) the format of the IE (T, V, TV, LV, TLV) as defined in GSM 04.07;

6) the length of the IE (or permissible range of lengths), in octets, in the message, where "?" means that the maximum length of the IE is only constrained by the link layer protocol, and in the case of the facility IE by possible further considerations specified in GSM 04.10. This indication is non-normative.

c) subclauses specifying conditions for IEs with presence requirement C or O in the relevant message. Together with other conditions specified in GSM 04.80, GSM 04.10 or GSM 04.8x and 04.9x-series this defines when the IE shall be included or not, what non-presence of such IEs means, and (for IEs with presence requirement C) the static conditions for presence and/or non-presence of the IEs (see GSM 04.07).

2.2 Messages for supplementary services control

Table 2.1 summarizes the messages for call independent supplementary services control (see GSM 04.10 for a detailed description of call independent supplementary service messages).

Table 2.1: Messages for call independent supplementary service control

Messages for supplementary service control

Reference

FACILITY

2.3

REGISTER

2.4

RELEASE COMPLETE

2.5

2.3 Facility

This message is sent by the mobile station or the network to request or acknowledge a supplementary service. It is used when information is to be conveyed and the transaction already exists, but is not to be released. The supplementary service to be invoked, and its associated parameters, are specified in the Facility information element (see table 2.2).

Table 2.2: FACILITY message content

IEI

Information element

Type / Reference

Presence

Format

Length

Supplementary service

Protocol discriminator

M

V

1/2

protocol discriminator

3.2

Transaction identifier

Transaction identifier

M

V

1/2

3.3

Facility

Message type

M

V

1

message type

3.4

Facility

Facility

M

LV

2-?

3.5

2.4 Register

2.4.1 Register (network to MS direction)

This message is sent by the network to the mobile station to assign a new transaction identifier for call independent supplementary service control and to request or acknowledge a supplementary service (see table 2.3).

Table 2.3: REGISTER message content (network to MS direction)

IEI

Information element

Type / Reference

Presence

Format

Length

Supplementary service

Protocol discriminator

M

V

1/2

protocol discriminator

3.2

Transaction identifier

Transaction identifier

M

V

1/2

3.3

Register

Message type

M

V

1

message type

3.4

1C

Facility

Facility

M

TLV

2-?

3.5

2.4.2 Register (MS to network direction)

This message is sent by the mobile station to the network to assign a new transaction identifier for call independent supplementary service control and to request or acknowledge a supplementary service (see table 2.4).

Table 2.4: REGISTER message content (MS to network direction)

IEI

Information element

Type / Reference

Presence

Format

Length

Supplementary service

Protocol discriminator

M

V

1/2

protocol discriminator

3.2

Transaction identifier

Transaction identifier

M

V

1/2

3.3

Register

Message type

M

V

1

message type

3.4

1C

Facility

Facility

M

TLV

2-?

3.5

7F

SS version

SS version indicator

O

TLV

3

3.7.2

2.4.2.1 SS version

This information element shall be included if the supplementary service operation being invoked is implemented according to the phase 2 or higher protocol version.

2.5 Release complete

This message is sent by the mobile station or the network to release a transaction used for call independent supplementary service control. It may also request or acknowledge a supplementary service (see table 2.5).

Table 2.5: RELEASE COMPLETE message content

IEI

Information element

Type / Reference

Presence

Format

Length

Supplementary service

Protocol discriminator

M

V

1/2

protocol discriminator

3.2

Transaction identifier

Transaction identifier

M

V

1/2

3.3

Release Complete

Message type

M

V

1

message type

3.4

08

Cause

Cause

O

TLV

4-32

GSM 04.08

1C

Facility

Facility

O

TLV

2-?

3.5

2.5.1 Cause

This information element shall be included when the functional handling of the Cause IE is specified in the service description or GSM 09.11. If the functional handling of the Cause IE is not specified, the receiving entity may ignore the IE.

2.5.2 Facility

This information element shall be included as required by the service description and the procedures defined in GSM 04.10.