1 Cigalegsmswbasics v6.2 Ats Ra
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Transcript of 1 Cigalegsmswbasics v6.2 Ats Ra
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1Astellia confidential
www.astellia.com
Cigale GSM basics
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At the end of the lesson the student will be able to:
Describe the GSM architecture Define the technical characteristics of Cigale Understand the Interests of Cigale Understand the usage of the different tools Describe the A-Interface protocol Understand the different Basic call flow
ObjectivesObjectives
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GSM Architecture
GSM OverviewGSM Overview
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Post processing software of GSM A interface capture frames:
Works under PC windows
Manages several types of capture platforms
Processing on specific time ranges and by time intervals
Processes Gigabytes of data
Technical Technical charactericticscharacterictics
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Measure and help for QoS improvement:
Detection of shortcomings : radio, BSS, NSS, transmission (PCM, CICs, transcoders)
Generation of both user and system oriented indicators
Investigation of user or network problems
Optimization (radio) and dimensioning
Information for marketing
InterestsInterests
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Statistics: Complementary to those of OMCs and manufacturer tools, more
accurate Manufacturer independent
Investigations: Better approach (more global) than a simple protocol analyzer Possibility of quickly isolating specific groups of users who
encounter problems (roamers, data calls, ) Troubleshooting with Activity Analysis
InterestsInterests
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Shortcomings detection: Allocation issues (looped PCM, CIC Pb) Traffic less cells (blocked TS) Handover failures (by cells couples), bad neighbourhood
declarations, parameter settings Radio drops (interferences) Saturations (radio, network, queuing) Paging efficiency Roaming (location updates failures) SMS efficiency (statistics per SMS Center)
InterestsInterests
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Examples
QoS indicators SDCCH failures, assignment failures, TCH drops Call setup efficiency, established calls drops Inter BSC handover successes Location update success rates SMS sending and reception success rates
Investigation ExamplesInvestigation Examples
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Investigation with Cigale view High call drop rates Handovers inefficiency, ping-pong handovers Location update rejects
Deeper investigation with Activity Analysis Too long call setup durations (according to the called numbers) Data calls discrimination Location update rejects (per IMSI) Calls traces per identities (IMSI, IMEI, numbers)
Investigation ExamplesInvestigation Examples
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Software architectureSoftware architecture
SQL
Txt files
XL3 files
Cigale GSM
Cigale Roaming
Activity Analysis
Cigale View
Roaming View
SLM
Cigale Trace Activity AnalysisRoaming AnalysisTrace AnalysisSLM Analysis
Trending & aggregation
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Processing & Viewers
SotwareSotware architecturearchitecture
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Cigale Engine
Processing & viewersProcessing & viewers
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Cigale View
Processing & viewersProcessing & viewers
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Activity Analysis
Processing & viewersProcessing & viewers
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Way to use the ToolsDetections of lack of QoS, thanks to statistics
Detailed causes
Calls impacted by a specific cause
Flow chartAvailable in V5.5
Protocol decoding
Statistic(View)
Troubleshooting(Activity Analysis)
Processing & viewersProcessing & viewers
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Characteristics of the main layers Several protocol layers manage the messages exchange between the
mobile terminal and the network
SCCP: connection management between MSC and BSC for every MS
BSSAP: divided in two parts- BSSMAP: procedures between BSC and MSC related to a MS
(HO execution for example)- DTAP: messages directly exchange between the MS and the MSC
MM, CM: Mobility & Connection Management- MM include message related to the mobility and the security- CM include call treatment (CC), supplementary services (SS) and short messages
services (SMS)
A interface protocolsA interface protocols
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MTP1
MTP2
MTP3
SCCP
MTP1
MTP2
MTP3
SCCP
A interface protocolsA interface protocols
Ph. Layer
LAPDm
RR
MM
CM
Ph. Layer
LAPD
RR
(+BTSM)
DTAP BSSMAP
BSSAP
distribution function
DTAP BSSMAP
MM
CM
BSSAP
distribution function
Direct dialogue between peer entities
Air Interface
AbisInterface
MS BSC MSC
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Ph LayerIP
SCTPM2UAMTP3B
M3UA
SCCP
Ph LayerIP
SCTPM2UA
MTP3BM3UA
MTP1MTP1
MTP2 MTP2
MTP3
SCCP
A interface A interface protocolsprotocolsNGN ArchitectureNGN Architecture
Ph. Layer
LAPDm
RR
MM
CM
Ph. Layer
LAPD
RR
(+BTSM)
DTAP BSSMAP
BSSAP
distribution function
Direct dialogue between peer entities
Air Interface
AbisInterface
MS BSC
DTAP BSSMAP
MM
CM
BSSAP
distribution function
MSSMGW (SGW)
MTP3
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Description of the SCCP messages
SCCP connection establishment- Request : Connection Request, CR- response OK : Connection Confirm, CC- Refusal : Connection Refused, CREF
Sending of messages : Data Form 1, DT1
Release of an SCCP connection- request : Released, RLSD- confirmation : Release Complete, RLC
A interface protocolsA interface protocols
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BSS MSCCR [ CL3I [ LUREQ ] ]Connection Request [ Complete Layer 3 Information [ Location Updating Request ] ]
CCConnection Confirm
BSS MSCCR [ HOREQ ]Connection Request [ Handover Request ]
CC [ HORAC [ HOCMD_RR ] ]Connection Confirm [ Handover Request Acknowledge [ Handover Command (RR) ] ]
Details of proceduresDetails of procedures
Location Update:
Incoming Handover driven by the MSC
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CHANNEL REQUESTIMMEDIATE ASSIGNMENT Establishment of a RR
connection
ALERTING Call confirmation
CONNECT ACK Call startedCONNECT
ASSIGNMENT CMDASSIGNMENT CMP Allocation of a traffics channel
MSGSM NETWORK RTCP or RNIS
CM SERVICE REQUEST Service Indication
AUTHENTICATION REQUESTAUTHENTICATION RESPONSE Authentication
CIPHERING MODE CMDCIPHERING MODE COMPLETE Ciphering mode
SET UPCALL PROCESSING Call routing
Details of Originating CallDetails of Originating Call
Originating call
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PAGING REQUEST
ALERTING Call confirmation
CONNECT ACKCall startedCONNECT
ASSIGNMENT CMDASSIGNMENT CMP Allocation of a traffics channel
MSGSM NETWORK RTCP or RNIS
AUTHENTICATION REQUESTAUTHENTICATION RESPONSE Authentication
CIPHERING MODE CMDCIPHERING MODE COMPLETE Ciphering mode
SET UPCALL CONFIRMED Call routing
CHANNEL REQUEST
IMMEDIATE ASSIGNMENT
Establishment of a RR connection
Service Indication PAGING RESPONSE
Details of Terminating Details of Terminating CallCall
Terminating call
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CHANNEL REQUESTIMMEDIATE ASSIGNMENT Establishment of a RR
connection
LOCATION UPDATING ACCEPT
CHANNEL RELEASE
TMSI REALLOCATION CMD
Allocation of a temporary identity
MSGSM NETWORK RTCP or RNIS
MM LU REQUEST Service Indication
AUTHENTICATION REQUESTAUTHENTICATION RESPONSE Authentication
CIPHERING MODE CMDCIPHERING MODE COMPLETE Ciphering mode
TMSI REALLOCATION CMP
LU accepted
Radio resource released
Details of Location Update Details of Location Update procedureprocedure
Location Update
TMSI reallocation only for the first location update and for location update between VLR