Presented by : Suparna Vadlamudi

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Presentation on IS-41

• Presented by Suparna Vadlamudi
• Vineela Solipuram
• Archana Paaka

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Agenda

• Introduction to IS-41
• Network Architecture
• Reference Model
• Function supported by IS-41
• Security Issues
• Conclusion
• References

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Introduction to Is-41

• IS-41 stands for Interim Standard-41.
• IS-41is a technical standard for mobile network
  signaling.
• The IS-41 specification provides a standard
  protocol for the mobility management for
  subscriber moving between different MSCs.
• IS-41 prescribes the network model, functions
  protocols and services that provide mobile
  telecommunications network intersystem
  operations.
• IS-41 was developed in the year 1988 by TIA-TR-45

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IS-41 Network Level Architecture
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IS-41Reference Model
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IS-41Reference Model (Revision C)
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IS-41 Supported Functions

• Calling Processing Functions
• Mobility Management Functions
• Automatic Roaming
• Short Messaging Services
• OAM

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Call Processing in IS-41

• Functions that establish, maintain and release
  calls from the mobile subscriber .
• It consists of operations performed from the
  initial acceptance of an incoming call through
  the final disposition of the call.
• There are basically divided into three categories
  
• Call origination functions
• Call termination function
• Feature control functions

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Call Origination Services

• Basic call origination
• Subscriber PIN Intercept (SPINI)
• Calling number identification restriction (CNIR)
• Message Waiting notification (MWN)
• Voice message retrieval (VMR)
• Call transfer (CT)
• Three way calling (3WC)
• Conference calling (CC)

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Basic Call Origination
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Call Origination Digit Analysis Trigger Process
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Call Origination Authentication Process
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Call termination Services

• Call delivery (Basic call termination)
• Call forwarding (Unconditional, default, no
  answer, busy)
• Call waiting (CW)
• Do not disturb (DND)
• Selective call acceptance (SCA)
• Password call acceptance (PCA)
• Mobile access hunting (MAH)
• Flexible Alerting (FA)

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Call termination call delivery Failure
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Call termination call delivery Failure (Contd..)
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Communications Inter system handoff
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Basic Intersystem Handoff

• Handoff encompasses a set of mobile station (MS)
  functions and network functions that enable an MS
  to move from one radio channel to the other.
• There are 2 categories of Handoff
• -Intra system handoff
• -Inter system handoff

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Basic Inter system Handoff
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Basic Inter system Handoff
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Basic Inter system Handoff
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Handoff Forward
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Handoff forward
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Handoff forward
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Handoff Forward
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Handoff forward
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Handoff Back
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Handoff Back
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Handoff Back
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Handoff Back
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Path minimization
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Path minimization
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Call Release
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Call Release
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Automatic Roaming

• Automatic roaming encompasses a set of network
  functions that allow a subscriber to obtain
  mobile telecommunications service outside the
  home service provider area.

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Communications For Roaming
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Registeration
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Automatic Roaming

• Functions related to automatic Roaming
• Mobile station service qualification
• MS location management
• MS state management
• HLR and VLR fault recovery

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MS Service Qualification

• Service qualification using Registration
  notification

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MS Service Qualification

• Service qualification using Qualification Request
  operation

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MS Location management
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MS State Management
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MS State management
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MS State management
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HLR VLR Fault Recovery Process
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HLR VLR Fault Recovery Process
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What is SMS?

• Short message service (SMS) is a service that
  enables the transmission of alphanumeric messages
  between mobile subscribers and external systems
  such as electronic mail, paging, and voice-mail
  systems .
• IS-41C specifies a set of data services
  collectively known as SMS

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Basic Network Architecture for an SMS Deployment
(IS-41)
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IS-41-C specified SMS Functions

• Short message entity(SME)service qualification
• SME location management
• SME state management
• Short message processing

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SME service qualification using registration
notification operation
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SME location management

• SME Location Update
• SME location Cancellation
• To update location
• 
  RegistrationNotification
• To cancel location
• 
  MSInactive,including the Deregistration parameter
• 
  BulkDeregistration
• Registration
  Cancellation
• 
  UnrelaibleRoamerDataDirective

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MS-based SME message origination
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Origination-Termination involving Different
Network Technologies
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Categories of SMS

• SMS bearer service
  
  
• SMS Teleservices
• These services require 2 functional entites
• (i)MC (Message Center)
• (ii)SME(Short Message Entity)
• Lets view what is SMS bearer service
• Its a basic transport mechanism.
• Allows Flexibility.
• This Service is designed to use any 1 of the
  following protocals
• Signaling System No.7(SS7)
• X.25
• Internet protocal

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Let see the basic architecture(figure)
supporting these protocals
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Security Issues

• Authentication of mobile station registration
• Unique challenge response procedures
• Authentication of MS originating a call
• Authentication of a call to a terminating MS

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Generation of Shared Secret Data in IS-41
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IS-41 Signature Calculation in IS-41
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Conclusions

• IS-41 standardizes all the functions required for
  mobility management.
• IS-41 provides more enhanced function when it is
  used to interoperate with other protocols (e.g.
  SS7 X.25)

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References

• Mobile Telecommunications Networking with IS-41c
• Authors Michael D. Gallagher , Randall A.
  synder
• http//www.qualcomm.com.au/PublicationsDocs/AUUG99
  AuthSec.pdf
• http//eeweb1.poly.edu/stefanov/IS41.pdf
• http//www.ifast.org/files/IFAST17_009_IS41Present
  ation.pdf
• http//www.funsms.net/sms_tutorial.htm

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Question-1

• What are the five functions that are supported by
  IS-41?
• 1.Calling Processing Functions
• 2.Mobility Management Functions
• 3.Automatic Roaming
• 4.Short Messaging Services
• 5.Operations, Administration Maintenance

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Question-2

• What is difference between Inter system handoff
  and Intra system handoff?
• Intra system handoff is between two radio
  channels that are controlled by the same MSC. No
  coordination is required between MSCs to support
  intra system handoff.
• Inter system handoff is a handoff between two
  radio channels that are controlled by two
  different MSCs. This type of hand-off requires
  specialized signaling between the two MSCs to
  coordinate the movement of MS between the two
  radio channels.

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Question-3

• What is SMS?
• Short message service (SMS) is a service that
  enables the transmission of alphanumeric messages
  between mobile subscribers and external systems
  such as electronic mail, paging, and voice-mail
  systems .