Presented by : Suparna Vadlamudi Vineela Solipuram Archana Paaka Presentation on IS-41

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

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 MSC’s. 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

IS-41 Network Level Architecture

IS-41Reference Model

IS-41Reference Model (Revision C)

IS-41 Supported Functions Calling Processing Functions Mobility Management Functions Automatic Roaming Short Messaging Services OA&M

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

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)

Basic Call Origination

Call Origination Digit Analysis Trigger Process

Call Origination Authentication Process

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)

Call termination – call delivery Failure

Call termination – call delivery Failure (Contd..)

Communications Inter system handoff

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

Basic Inter system Handoff

Handoff Forward

Handoff forward

Handoff Forward

Handoff forward

Handoff Back

Path minimization

Call Release

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.

Communications For Roaming

Registeration

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

MS Service Qualification Service qualification using Registration notification

MS Service Qualification Service qualification using Qualification Request operation

MS Location management

MS State Management

MS State management

HLR VLR Fault Recovery Process

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 voic systems. IS-41C specifies a set of data services collectively known as SMS

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

IS-41-C specified SMS Functions Short message entity(SME)service qualification SME location management SME state management Short message processing

SME service qualification using registration notification operation

SME location management 1. SME Location Update 2. SME location Cancellation To update location: RegistrationNotification To cancel location: MSInactive,including the Deregistration parameter BulkDeregistration Registration Cancellation UnrelaibleRoamerDataDirective

MS-based SME message origination

Origination-Termination involving Different Network Technologies

Categories of SMS 1. SMS bearer service 2. SMS Teleservices These services require 2 functional entites (i)MC (Message Center) (ii)SME(Short Message Entity) Lets view what is SMS bearer service It’s 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

Let see the basic architecture(figure) supporting these protocals

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

Generation of Shared Secret Data in IS-41

IS-41 Signature Calculation in IS-41

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)

References Mobile Telecommunications Networking with IS-41c Authors: Michael D. Gallagher, Randall A. synder Sec.pdf Sec.pdf

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

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 MSC’s to support intra system handoff. Inter system handoff is a handoff between two radio channels that are controlled by two different MSC’s. This type of hand-off requires specialized signaling between the two MSC’s to coordinate the movement of MS between the two radio channels.

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 voic systems.