7 Protocol modelling principles

3GPP44.001General aspects and principlesMobile Station - Base Station System (MS - BSS) interfaceRelease 16TS

7.1

The signalling protocols on the MS-BSS Interface are specified using the concepts of the reference model of Open System Interconection (OSI) given in ITU-T Recommendations X.200 and X.210.

7.2

The basic structuring technique in the OSI reference model is layering. According to this technique, communication among application processes is viewed as being logically partitioned into an ordered set of layers represented in a vertical sequence as shown in figure 3.

+———————-+

| Highest layer |

+———————-|

| |

+———————-|

| (N + 1)-layer |

+———————-|

| (N)-layer |

+———————-|

| (N – 1)-layer |

+———————-|

| |

+———————-|

| Lowest layer |

+———————-+

Figure 3: Layering

Entities exist in each layer. Entities in the same layer, but in different systems which must exchange information to achieve a common objective are called "peer entities". Entities in adjacent layers interact through their common boundary. The services provided by the (N + 1)-layer are the combination of the services and functions provided by the (N)-layer and all layers below the (N)-layer.

Management functions may also be required. They may include functions which are common for several layers and are not supported by the services provided by a specific layer. Examples of such functions are error reporting, status reporting and management of the operation of certain layers. Such management functions do not require that peer-to-peer messages are sent across the MS-BSS interface.

7.3

For signalling on the MS-BSS interface three layers are required as shown in figure 4.

+——————–+

| |

| Layer 3 |

| |

+——————–|

| Data link layer |

| |

+——————–|

| |

| Physical layer |

| |

+——————–+

Figure 4: Layering on the MS-BSS interface

The layers are:

– PHYSICAL LAYER which corresponds to the lowest layer. The functions and protocols of the physical layer are defined in Technical Specification 3GPP TS 44.004.

– DATA LINK LAYER. The functions and protocols of the data link layer are defined in Technical Specifications 3GPP TS 44.005 and 3GPP TS 44.006.

– LAYER 3. The functions and protocols of layer 3 are defined in Technical Specifications 3GPP TS 24.007, 3GPP TS 24.008, 3GPP TS 24.010, 3GPP TS 24.011 and 3GPP TS 44.012.

7.4

Layer-to-layer interactions are specified in terms of service primitives. The primitives represent, in an abstract way, the logical exchange of information and control between adjacent layers. They do not specify or constrain implementation.

Primitives are also used to describe information exchange between layers and the mobile management entity.

The primitives that are exchanged between the (N + 1)-layer and the (N)-layer are of the following four types (see figureĀ 5).

+————-+ +————-+

|(N + 1)-layer| |(N + 1)-layer|

+————-+ +————-+

| | | |

Confirm| |Request | |

| | Indication| |Response

|_________| |_________|

/| |\ /| |\

| * | | * |

\|_________|/ \|_________|/

| | | |

| | | |

| | | |

+-+———+-+ +-+ +-+———+-+

| | +-+ ->- – + + – – +-+ | |

| |(N)-layer | | | | (N)-layer| |

| +———–+ – – – + + -<- +———–+ |

+————-+ +-+ +————-+

|

+(N)-layer peer-to-peer
protocol

Figure 5: Primitive action sequence for peer-to-peer communication

The REQUEST primitive type is used when a higher layer is requesting a service from the next lower layer.

The INDICATION primitive type is used by a layer providing a service to notify the next higher layer of activities related to the primitive type REQUEST.

The RESPONSE primitive type is used by a layer to acknowledge receipt, from a lower layer, of the primitive type INDICATION.

The CONFIRM primitive type is used by the layer providing the requested service to confirm that the activity has been completed.

Annex A (informative):
Change History

Meeting No.

TDoc. No.

CR. No.

Section affected

New version

Subject/Comments

SMG#07

4.0.4

Phase 2 version

SMG#20

5.0.0

Release 1996 version

SMG#27

6.0.0

Release 1997 version

SMG#29

7.0.0

Release 1998 version

SMG#31

8.0.0

Release 1999 version

CN#11

4.0.0

Release 4 version

NP-16

NP-020224

001

4.1.0

Various clean-up of wrong references

NP-16

5.0.0

Plenary decision to make this TS also for Rel-5.

NP-26

6.0.0

Plenary decision to make this TS also for Rel-6.

7.0.0

Plenary decision to make this TS also for Rel-7.

CP-42

8.0.0

Plenary decision to make this TS also for Rel-8.

CP-46

9.0.0

Plenary decision to make this TS also for Rel-9.

CP-51

10.0.0

Plenary decision to make this TS also for Rel-10.

CP-57

11.0.0

Plenary decision to make this TS also for Rel-11.

CP-65

12.0.0

Plenary decision to make this TS also for Rel-12.

CP-70

13.0.0

Upgrade to Rel-13

Change history

Date

Meeting

TDoc

CR

Rev

Cat

Subject/Comment

New version

2017-03

SA#75

Upgrade to Rel-14

14.0.0

2018-06

SA#80

Upgrade to Rel-15

15.0.0

2020-06

SA#88e

Upgrade to Rel-16

16.0.0