GSM protocols chuyen de vien thong

1
The ISO 7-Layer OSI Model
2
GSM Protocols Overview
3
GSM Transmission Protocols
GSM Protocols
The ISO 7-Layer OSI Model

Development of the Open System Interconnection
(OSI) reference model was started in 1983

It was eventually adopted as an international
standard by the International Standards
Organisation (ISO) and is currently embodied within
the ITU-TS X.200 Recommendation.
The ISO 7-Layer OSI Model

The model comprises 7 layers. These 7 layers are generally viewed in
two blocks :

Application Functional Layers. These are layers 4-7 of the OSI Model.

Network Functional Layers. These are layers 1 -3 of the OSI Model.
The ISO 7-Layer OSI Model
The ISO 7-Layer OSI Model
The ISO 7-Layer OSI Model
Layer 1: The physical layer

This layer conveys the bit stream through the network at the electrical and
mechanical level. It provides the hardware means of sending and receiving data

on a carrier.
Layer 2: The data-link layer

This layer provides synchronization for the physical level and does bit-stuffing for
strings. It furnishes transmission protocol knowledge and management.
Layer 3: The network layer

The network layer does routing and forwarding.
Layer 4: The transport layer

This layer manages the end-to-end control (for example, determining
whether all packets have arrived) and error-checking. It ensures complete
data transfer.
Layer 5: The session layer

This layer sets up, coordinates, and terminates conversations, exchanges, and
dialogs between the applications at each end. It deals with session and
connection coordination.
Layer 6: The presentation layer

This is a layer, usually part of an operating system, that
converts incoming and outgoing data from one presentation format to another.
This layer is sometimes called the syntax layer.
Layer 7: The application layer

This is the layer at which communication partners are identified, quality of
service is identified, user authentication and privacy are considered.
GSM Protocols Overview
GSM Protocol Layers :GSM protocols are basically
divided into three layers:

Layer 1: Physical layer
Layer 2: Data link layer
Layer 3: Network layer
Layer 1: Physical layer

Enables physical transmission (TDMA, FDMA)

Assessment of channel quality

Definition of physical links

Error detection
Layer 1 Services:

Access Capabilities

Error Detection

Encryption
Layer 2: Data link layer

Multiplexing of one or more layer 2
connections on control/signalling

Channels

Error detection

Flow control


Transmission quality assurance

Routing
Layer 2 : Data Link layer
Layer 2 Services :

The LAPDm protocol is used

Connectionless transfer on point-to-point and
point-to-multipoint signalling channels

Setup and take-down of layer 2 connections on
point-to-point signalling channels
Layer 3: Network layer

Connection management

Management of location data

Subscriber identification

Management of Services
Layer 3 services:
Contains the following sublayers which control
signalling channel functions (BCH, CCCH and
DCCH):

Radio resource management (RR).

Mobility management (MM).


Connection management (CM)
Transmission protocols relate to the physical
transportation of raw data across the GSM
network and the various protocols
associated with this function

3.GSM Transmission Protocols
GSM Transmission Protocol Stack
(TRAU at MSC)
TRAU Configurations