switching systems lecture7
TRANSCRIPT
DIT
Dar es Salaam institute of Technology (DIT)
ETU 07420
Switching Systems
Ally, J
DIT
Mobile Core Network Overview
DIT
GSM system overview The GSM system is a frequency- and time-division
cellular system, each physical channel is characterized by a carrier frequency and a time slot number
Cellular systems are designed to operate with groups of low-power radios spread out over the geographical service area. Each group of radios serve MSs presently located near them. The area served by each group of radios is called a CELL
Uplink and downlink signals for one user are assigned different frequencies, this kind of technique is called Frequency Division Duplex (FDD)
Data for different users is conveyed in time intervals called slots , several slots make up a frame. This kind of technique is called Time Division Multiple Access (TDMA)
DIT
GSM DevelopmentStandard Protocol for GSM take effect
System was named as Global System for Mobile Communication
GSM system began to provide service in Europe(2G)
Provide services for the whole world
Micro Cell Technique is used in GSM system
1989
1991
1992
1994
1996
DIT
GSM-GPRS Network Component
GSM /GPRS BSS
BTS
BSC
BTS
BSC
PCU
SS7
SMS system
PSTNISDN
Internet,Intranet
MSC/VLR GMSC
HLR/AUC
SGSN
CG BG
GGSN
GPRS Backbone
Other PLMN
MS
MS
OMC
DIT
Mobile Station—MS
International Mobile Equipment Identity (IMEI)
– Mobile Equipment
MS=ME+SIM
International Mobile Subscriber Identity (IMSI)
– Subscriber Identity Module
DIT
Subscriber Identity Module – SIM
International Mobile Subscriber Identity
(IMSI)
Temporary Mobile Subscriber Identity
(TMSI)
Location Area Identity (LAI)
Subscriber Authentication Key (Ki)
SIM
DIT
BTS
BSC
TC/SMBSS
MSC
Base Station Subsystem – BSS
The Base Station Controller – BSC
The Base Transceiver Station – BTS
The Trans-coder – TC and Sub multiplexer (SM)
DIT
BTS
BSC
TC/SMBSS
MSC
Packet Control Unit-----PCU
Packet data switching
Bridge between SGSN and BSC
Provide Pb and Gb interface
GPRS Backbone
PCU SGSN
DIT
Mobile-service Switching Center – MSC Home Location Register – HLR Visitor Location Register – VLR Equipment Identity Register – EIR Authentication Center – AUC Echo Cancellor – EC
AUCHLR
MSC/VLR
PSTN
NSSEIROMC
BSS
EC
The Network Switching System
DIT
Mobile-Service Switching Center – MSC Call Processing
Operations and Maintenance Support
Interface management
Inter-network & Inter-working Inter-network: communication between GSM network and other network
Inter-working : communication between different entities inside the GSM network Billing
DIT
Home Location Register – HLR
Subscriber ID (IMSI and MSISDN)
Current subscriber VLR (current location)
Supplementary service information
Subscriber status (registered/deregistered)
Authentication key and AuC functionality
DIT
Visitor Location Register – VLR Mobile Status (IMSI attached / detached /
busy / idle etc.)
Location Area Identity (LAI)
Temporary Mobile Subscriber Identity (TMSI)
Allocating the Roaming Number
DIT
IMEI is Checked In White List
IMEI is Checked in Black/Grey List
If NOT foundEIR focus on the equipment , not the subscriber!!
Equipment Identity Register – EIR
White List Black List Grey List
DIT
OMC Functional Architecture
OSMMI
DB
Event/AlarmManagement
SecurityManagement
ConfigurationManagement
Performance Management
Fault Management
DIT
Service Area
PLMN service area
......
Service Area
MSC service area...
Location area...
cell
PLMN service area PLMN service area
MSC service area...
Location area...
cell
DIT
LAI
Location Area Identification
The LAI is the international code for a location area.
MCC: Mobile Country Code ， It consists of 3 digits . For example: The MCC of Tanzania is “640"MNC: Mobile Network Code ， It consists of 2 digits . For example: The MNC of Vodacom is "03"LAC: Location Area Code ， It is a two bytes hex code. The value 0000 and FFFF is invalid.For example: 640-03-0011
MCC MNC LAC
DIT
CGI
The CGI is a unique international identification for a cellThe format is LAI+CI
LAI: Location Area Identification
CI: Cell Identity. This code uses two bytes hex code to identify the cells within an LAI.
For example : 640-03-0011-0001
CGI: Cell Global Identification
DIT
BSIC
NCC: PLMN network color code. It comprises 3 bit. It allows various neighboring PLMNs to be
distinguished.BCC: BTS color code. It comprises 3 bit, used to
distinguish different cells assigned the same frequency!
NCC BCC
BSIC
BSIC （ Base Station Identification Color Code)
DIT
CC: Country Code. For example: The CC of Tanzania is “255".NDC: National Destination Code. For example: The NDC of
vodacomis 75 and 76.SN: Subscriber Number. Format:H0 H1 H2 H3 ABCDExample: 255-75-0666234
MSISDN
CC NDC SNNational (significant)
Mobile number
Mobile station internationalISDN number
DIT
MCC: Mobile Country Code ， It consists of 3 digits . For example: The MCC of Tanzania is "640"。MNC: Mobile Network Code ， It consists of 2 digits . For example: The MNC of Vodacom is "03"。MSIN: Mobile Subscriber Identification Number. H1H2H3 S ABCDEF For example: 75-0666234NMSI: National Mobile Subscriber Identification ， MNC and MSIN
form it together. For Example of IMSI : 640-03-75-0777001
Not more than 15 digits
3 digits 2 digits
IMSI
MCC MNC MSINNMSI
IMSI
DIT
TMSI
The TMSI is assigned only after successful subscriber authentication.
The VLR controls the allocation of new TMSI numbers and notifies them to the HLR.
TMSI is used to ensure that the identity of the mobile subscriber on the air interface is kept secret.
The TMSI consists of 4 bytes( 8 HEX numbers) and determined by the operator.
TMSI: Temporary Mobile Subscriber Identification)
DIT
IMEI
TAC FAC SNR SP
IMEI
IMEI: International Mobile Station Equipment Identification
TAC: Type Approval Code, 6 bit, determined by the type approval centerFAC: Final Assembly Code, 2 bit, It is determined by the manufacturer.SNR: Serial number, 6 bits, It is issued by the manufacturer of the MS. SP: 1 bit , Not used. Check the IMEI in your MS : *#06#
DIT
UMTS R99 Network Architecture
GSM /GPRS BSS
BTS
BSC
NodeB
RNC
PCU
UMTS UTRAN
SS7
SCPSMS
SCE
Other PLMN PSTN,ISDN
Internet,Intranet
MSC/VLR GMSC
HLR/AUC
SGSN
CG BG
GGSN
GPRSbackbone
Other PLMN’s GPRS network
DIT
R99 CN Feature Core Network is split into CS domain and PS domain.
CS domain is in charge of call control and mobility management of circuit service.
Call control: ISUP/TUP Mobility management: enhanced MAP Physical node:MSC,GMSC,VLR
PS domain is in charge of session management and mobility management of Packet service.
There are some change from GPRS: interfaces, flows, some functions
Physical node: SGSN,GGSN,CG Transcoders is placed in CN side TFO: Tandem Free Operation Supporting inter-system handover (UMTS/GSM)
DIT
UMTS R4 Network Architecture
GSM /GPRS BSS
BTS
BSC
NodeB
RNC
PCU
UMTS UTRAN
SS7
SCPSMS
SCE
Internet,Intranet
HLR/AUC
SGSN
CG BG
GGSN
MGWMGW MGWMGW
VMSC Server GMSC Server
IP/ATM BackboneOther PLMN PSTN,ISDN
Other PLMN’s GPRS network
GPRSbackbone
DIT
R4 CN Feature CS domain
Control is separated from bearer,MSC is split into MSC server and MGW
Traffic bearer can be IP , ATM or TDM
Signaling bearer can be IP or TDM
TrFO: Transcoder Free Operation
DIT
MSC
SCP HLR
MSC
RAN RAN RAN
TDMMSC Server
SCP HLR
RAN RAN RAN
TDM/ATM/IPCS-MGW CS-MGW
MSC ServerTUP/ISUP/BICC
TUP/ISUP
Notes: PS domain structure remain unchangedR99 R4
H.248 H.248
MAP Over TDM MAP Over TDM/IPCAP Over TDM CAP Over TDM/IP
CS domain evolution
Difference Between R99 and R4
DIT
Interfaces in R99 network
GSM /GPRS BSS
BTS
BSC
NodeB
RNC
PCU
UMTS UTRAN
SS7
SCPSMS
SCE
PSTNISDN
Internet,Intranet
MSC/VLR GMSC
HLR/AUC
SGSN
CG BG
GGSN
Other PLMN
A
Gb
Iu-CS
Iu-PS
Gi
Gp
C/D/Gs
Gr/Gs/Gd/Ge Gc
GPRS backbone
Ga
DIT
MSC/VLR GMSC
Node B
RNC
HLR/AuC
GGSNSGSN
PSTN
GPRS backbone
CGF BG
SS7
SCP
Inter-PLMN
Iub
Iu-PS
Iu-CS
L1 （ PHY）ATM
AAL5
SSCOP
SSCF-NNI
MTP3B
SCCP
RANAP
AAL2
IuUPControl PlaneControl Plane User PlaneUser Plane
Iu-CS Interface Protocol Stack
DIT
SS7 Interface Protocol Stack
MSC/VLR GMSC
Node B
RNC
HLR/AuC
GGSNSGSNGPRS
backbone
CGF BG
SS7
SCP
Inter-PLMN
Iub
MAP
CAP
ISUP
TUPTCAP
SCCP
MTP3
MTP2
MTP1
BSSAP+
PSTN
DIT
PS Domain Interface Protocol Stack
MSC/VLR GMSC
Node B
RNC
HLR/AuC
GGSNSGSN
CGF BG
SS7
SCP
Inter-PLMN
Iub
L1 （ PHY）ATM
AAL5
SSCOP
SSCF-NNI
MTP3B
SCCP
RANAP
AAL5
GTP-UControl PlaneControl Plane User PlaneUser Plane
IPUDP
Iu-PS
GTP(GTP')
UDPIP
L2(MAC)L1(PHY)
Gn/Gp/Ga
GPRS backbone
PSTN
DIT
New Interfaces in R4
GSM /GPRS BSS
BTS
BSC
NodeB
RNC
PCU
UMTS UTRAN
SS7
SCPSMS
SCE
PSTNISDN
Internet,Intranet
HLR/AUC
SGSN
CG BG
GGSN
GPRS backbone
Other PLMN
MGWMGW MGWMGW
VMSC Server GMSC Server
IP/ATM Backbone
Nc
McNb
DIT
Interfaces in R4 CS Domain
MGW
Mc McNb
NcMSC
Server
MGW
GMSC Server
BICC/ISUP/TUP MTP3 MTP3B M3UA MTP2 SSCF/SSCOP SCTP MTP1 AAL5/ATM IP
H.248 SCTP UDP MTP3B
IP SSCF/SSCOP/AAL5
RTP AAL2 Voice UDP/IP ATM PCM
DIT
Wireless Intelligent Network (WIN)
DIT
Concept of Wireless Intelligent Network Wireless Intelligent Network (WIN) is a network in which the
functional entities of the Intelligent Network (IN) are introduced to the mobile network to realize the intelligent control to mobile calls.
It is the combination of the current mobile network and the intelligent network.
The introduction of the mobile service switching point into the mobile network has enabled the connection of the mobile network at the lower layer with the intelligent network at the higher layer, thus forming the wireless intelligent network.
As a high layer service network of the mobile network, WIN can create and realize all kinds of new mobile services rapidly, conveniently, flexibly, economically and efficiently, facilitating the customers to get the required information.
The major characteristic of WIN is that it separates the switching function from the control function of the network.
It processes the intelligent call with the support of Signaling System No.7 (SS7) network and large centralized database, while the original exchange only performs the basic connection functions.
DIT
Features of Wireless Intelligent Network Extensively using information processing technology
Effectively using network resources Modularizing the network functions that can be used
repeatedly Using the reusable modular network function to generate and
implement a new service Network functions being flexibly distributed in physical entities Portable network functions in a physical entity Providing standard communications between network
functions through the service-independent interfaces Service subscribers being able to control the service
properties defined by themselves Service users being able to control the service properties
defined by themselves Standardized management of service logic
DIT
Target of Wireless Intelligent Network WIN is aimed at providing the existing mobile network with
some additional abilities that facilitates the carriers to provide new services.
It is required that the newly-provided service should be independent from the network, i.e., the service is irrelevant to the equipment running in the mobile network and does not care about who provides the equipment.
The independent implementation of a service enables a service provider to define his own service without relying on the specific service products of the equipment vendor.
The independent implementation of the network enables a network operator to allocate the functions and resources within his network and manage his network effectively without relying on the specific network implementation mode of an equipment vendor.
DIT
Intelligent Network Layer
DIT
Evolution and Development of Wireless Intelligent Network
The study on WIN was started as early as 1995. At first, there was no concrete standard protocol, and
different companies laid down their own standards and have carried out a good deal of studies on such basis.
In January, 1998, European Telecommunications Standards Institute (ETSI) introduced Customised Application for Mobile network Enhanced Logic (CAMEL) in GSM Phase 2+. The version at that time is Phase 1.
With the accomplishment of CAMEL Phase 1 in GSM Phase 2+, the development of WIN has entered a new phase.
Thanks to the open interface provided by CAMEL Phase 1, the equipment from different manufacturers can interconnect with each other.
DIT
Architecture of Wireless Intelligent NetworkWIN is composed of
Service Switching Point (SSP)
Service Control Point (SCP)
Intelligent Peripheral (IP)
Service Management System (SMS)
Service Creation Environment (SCE)
DIT
Service Switching Point (SSP) SSP connects the mobile network to IN, providing IN access
function (IN call detection). SSP contains the capability to detect requests for IN services
and communicate with SCP. It responds to the requirements from SCP and enables SCP to affect the call flow with the service logic.
SSP contains Call Control Function (CCF) and Service Switching Function (SSF). If there is no independent IP established, SSP should also has part of Specialized Resource Function (SRF).
CCF is responsible for basic connection functions such as receiving user calls, performing call setup and call holding etc. SSF can receive and identify the intelligent service call and report to SCP, meanwhile it will accept the instruction from SCP as well.
SSP is generally based on Mobile Switching Center (MSC) and provided with the necessary software and hardware, as well as signaling No.7 network interface.
DIT
Service Control Point (SCP) SCP is the core component of the intelligent network, SCP
stores user data and service logic. SCP is responsible for receiving the querying information
from SSP, querying the database, and encoding the information in various ways.
SCP initiates different service logic according to call events reported from SSP, and sends call control instructions to the corresponding SSP according to service logic, that is the implementation of various IN calls.
All the service control functions provided by WIN are concentrated in SCP.
The communication between SCP and SSP is carried out based on the standard interface protocols of WIN.
SCP, which must be highly reliable, comprises minicomputers and large real-time high-speed databases.
DIT
Intelligent Peripherals IP is the special resource to consist the intelligent
service. Usually it contains various voice manipulation functions,
like combining voice, playing recorded announcements, receiving numbers sent in DTMF (Dual Tone Multi-Frequency), performing voice identification, and so on.
As the standalone equipment or part of SSP, IP can receive the control of SCP and perform the operation specified by SCP service logic.
If IP is set individually in the network, it can be shared by other switches, which is a cost cutting solution.
Meanwhile it is convenient for the uniform management of voice resource and helpful for the deployment of services whose voices are changed frequently.
DIT
Service Management System (SMS) SMS is the manager of WIN.
It has the following functions: service logic management, service data management, user data management, system data management and the management of daily operation and maintenance.
A new service logic created in SCE is transferred to SMS, then loaded to SCP by SMS to run the new service over the mobile network.
DIT
Service Creation Environment (SCE) SCE has the function of creating new service logic
according to the requirement from users. SCE provides the service designer with the friendly
graphical editing interface. Customer use the various standard graphical
elements to design the new service logic and define the relevant data.
After the designing, the service should first pass the strict verification and simulation, which is to ensure that the new service will not bring any negative influence to the existing services.
After that, SCE will transfer the service logic to SMS which will load it to SCP for running.
DIT
Creating and Loading a New ServiceThe procedures are described as follows:
Design a new service. Transfer the designed service to SMS. Load the logic program of the new service to SCP according to
the instruction of system administrator. The customer begins to use the new service.
DIT
Thanks!
Technology changes but communication lasts.