1. Signaling Technology Review

Steve Madden

Technical Marketing Engineer

Signaling Technology Review

2

Agenda

Introduction to Signaling and SS7

SS7 Network Infrastructure

SS7 Protocols

Evolution of Signaling (TDM to IP/SIGTRAN)

Signaling Applications

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What Is Signaling? How Is It used?

SIGTRAN (SIGnaling TRANsport) IP telephony protocol used to transfer SS7 signals over IP networks.

SS7 set of protocols used inside networks for wireline and wireless services.

M3UA M2PA

SCTP

IP

Physical

Using signaling technology, communications systems developers can

• Build large, scalable core network platforms (HLR, SMS-C, IP…)

• Integrate data and information to enable high-value services

• Manage advanced capabilities such as call forwarding, wireless roaming, and prepaid billing etc

4

Features of SS7

Single signaling channel may control many (voice, data) circuits. Signaling is on lines physically separated from voice/data.

Network protocol, very reliable and robust

Redundant hardware and routing (primary & alternate) paths to ensure high reliability

World-wide standard for digital networks, fixed and mobile

Backbone for ISDN, Mobile and Intelligent Networks (IN)

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Agenda

Introduction to SS7


SS7 Protocols

Evolution of signaling (TDM to IP/SIGTRAN)


6

SS7 Network Architecture

Signaling network separate from voice network

Purpose is to transport data messages between nodes for:

• Call control (wireline & wireless)

• Advanced services (e.g. SMS, LNP)

• Network management

All nodes are called Signaling points

• Message discrimination

• Route messages to another Signaling point

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Signaling Points

Uniquely identified by a numeric Point Code

Point codes are carried in messages to identify

• Source

• Destination

Each SP uses a routing table to select a signaling path

3 different types:

• Service Switching Point (SSP)

• Signal Transfer Point (STP)

• Service Control Point (SCP)

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Signaling Points review

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SS7 Terminology

Point Code

• Address of a Signaling Point in an SS7 network

• 14 bits in ITU-T, 24 bits in ANSI

Signaling link

• Logical channel carrying SS7 Signaling traffic

• Low Speed Link: 64 or 56 kb/s timeslot in an E-1/T-1 trunk or separate V.35 serial connection

• High Speed Link: 1.5 Mb/s (T1) or 2 Mb/s (E1)

• Usually configured to handle 20-40 % of available bandwidth

Link Set

• Collection of up to 16 Signaling links between two adjacent point codes

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Point Codes, Links and Link sets

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Circuit identification Code

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Base Station Subsystem

Mobile ApplicationsMobile ApplicationsRoaming Messaging Roaming Messaging

Location-based ServicesLocation-based Services

Intelligent NetworksIntelligent Networks800, LNP, Prepaid800, LNP, Prepaid

Mobile Switching

Center (MSC)

Home/VisitorLocation Register

(HLR/VLR)

Service ControlPoint(SCP)

SignalTransfer

Point(STP)

SS7/PSTN

Network

Signaling

Service Point(SSP)

localSwitch (SSP)

Network Architectures

CAMEL Service Environment

(CSE)

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Agenda

Introduction to SS7


SS7 Protocols



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SS7 is not just a single protocol

Suite of protocols

Each of the protocols have a defined interface and function

Why SS7 protocols?

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SS7 Protocols

MTP1

MTP2

MTP3

SCCP

TCAP

INAP/AIN(INAP- ETSI CAMEL-GSM)

IS41/GSM(IS41

IS826/WIN)

ISUP TUPCall Control

MessageTransferPart

Mobile/WirelessMessaging andIntelligentNetworking

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MTP 2

The link control layer

Ensures that messages (a.k.a. Signal Units) are sent point to point error free and in sequence

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MTP 3

Routing messages between various Signaling points in the network

Load sharing

Route failure management

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ISUP

ISDN User Part

Defines messages and procedures to support ISDN calls and supplementary services inside the network

Media (voice) is carried in a 64kbps timeslot, each timeslot is assigned a Circuit Identification Code

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Telephony architecture

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SCCP

Signaling Connection Control Part

Provides the capability of exchanging free format data (other than call control messages) between nodes in the SS7 network

Augments MTP3 addressing capabilities

Provides management of the state of the entities (sub-systems) that exchange data

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SCCP network architecture

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TCAP

Transaction Capabilities Application Part

Provides a structured interface to control operations executed between physically independent nodes in the SS7 network

Operations and their results are managed within a session (or a dialogue/transaction)

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TC Application parts

GSM-MAP: ETSI mobile application part (SMS, HLR interrogation, USSD …)

IS41-MAP: ANSI mobile application part

INAP: Intelligent networking (1-800, Intelligent call routing …)

CAMEL (Customised Application for Mobile Network Enhanced Logic

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SMS message flow

1. Mobile sends text message

2. MSC routestext message

to SMSC

3. SMSC asks HLRfor current location ofcalled subscriber

4. Message delivered tocalled subscriber

MSC/VLR

SMSC

HLRMSC/VLR

25

Agenda

Introduction to SS7


SS7 Protocols



26

The Signaling Future – coming soon!

The network is starting to shift to IP

SS7 is as important as ever – maybe even more so!

SIGTRAN is crucial

27

2.5 Generation Network - SS7 signaling

MSC

PrepaidHLR

RAN

AuC

EIR

VLR

GMSC

SGSN GGSN

SMSC

GMLC

GSM MAP SS7

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Typical Next Generation Network - a mix of signaling technology

IP Transport

Media Gateway

Signalling Gateway

Signalling Converter

PSTN

ISUP

DNPSS

ISUP

G704

RTP

ISUP/M3UA

SIPISUP/M3UA

Media Gateway controller

Signalling Converter

ISUP/M3UA

C5

SIGTRAN/SIP

Gateway

Media Gateway

RTP

SIP

MSC Server

SMSC

SIP-Diameter

IWF

Prepaid

CAPSUARo

CAP SUA

RoSIP ISC

E/SUASMS SIP Gateway

E/SUASIP

BICC ISUPM3UA

HLR/HSS

D/SUA

CSUA

Sh

H.248

RAN

SS7 over SIGTRAN

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What is SIGTRAN?

Suite of protocols including:

• SCTP – Stream Control Transmission Protocol

• M3UA – MTP3 User Adaptation Layer

• M2PA – MTP2 Peer to Peer Adaptation Layer

• M2UA – MTP2 User Adaptation Layer

• SUA – SCCP User Adaptation Layer

• IUA – ISUP User Adaptation Layer

Designed to carry SS7 messages over IP in a standards based way.

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SCTP

Common component to all SIGTRAN systems.

Allows point to point pipes to be created

• Interfaces directly to IP

• Reliable sequenced delivery

• Similar to TCP but better

Offers IP resilience ‘SCTP Multihoming’

Fast recognition of link failure

Fast retransmission procedures

Strong flow control procedures

M3UA M2PA

SCTP

IP

Physical

31

M2PA

M2PA unique to SIGTRAN

– it replaces MTP2 links.

Used between two point codes

Used over short or long distances

M3UA M2PA

SCTP

IP

Physical

32

M3UA, SUA ‘User Adaptation’ layers

M3UA enables MTP3 user Signaling e.g. SCCP, ISUP over SCTP

SUA enables SCCP User Signaling (TCAP) over SCTP

M3UA SUA

SCTP

IP

Physical

• Offer Standards based interface

• Interface to SCTP and SS7 protocols

• Transparently move SS7 from one place to the next

33

Agenda

Introduction to SS7


SS7 Protocols



34

Just a Few Applications Using Signaling …

Prepaid

Roaming

Push to Talk

SMS Router

Missed Call AlertCRBT

(Colour Ring Back Tone)

SoftSwitch

HLR(Home Location Register)

Number Portability

LBS(Location Based Service)

SMS Center

Unified Messaging

AuC(Authentication)

Billing

Call Control

35

Color Ring Back Tones

Replacement of traditional ring back tones by user-defined announcements (examples: songs, messages, sound effects)

Calling party hears the “color” ring

Called party subscribes to the service

Value added service designed for the youth market

segment

36

Call Enhanced with Color Ring Back Tones

1. Peter dials Maureen’s

mobile number

2. CRBT app looks up which

ring tone Maureen has selected

for Peter to hear

3. Peter hears Color Ring

Back Tone until Maureen answers

Color Ring Back Tones Demonstration

SS7G2x Signaling Server with ISUPSS7G2x Signaling Server with ISUP

Or Intelligent Network signalingOr Intelligent Network signaling

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Video Call Integration in SS7

Video CapableMobile Phone

MSC

3G(circuit

switched)

3G - 3

24M

on

E1IP

Video Gateway

Video Messaging Server SIP End

Points

RTP G.7

11SIP

3G – 324M

on E1

SIP

Q: How does a Video Service Provider connect to circuit switched mobileQ: How does a Video Service Provider connect to circuit switched mobile

networks to provide Video services?networks to provide Video services?

38

Video Video GatewayGateway

3G – 324M3G – 324M

Signaling Signaling ServerServerSS7G21SS7G21

SS7 ISUPSS7 ISUP

RTP G.7

11

RTP G.7

11SIPSIP

Video Video CapableCapableMobile Mobile PhonePhone

MSC

3G

3G 324M Using ISDN PRI or SS7

IPVideo Gateway

Video Video Messaging Messaging

ServerServer

SIP End Points

RTP G.711SIP

3G –324M

SIP

• ‘Video Gateway’ acts as SIU host

• Enables the Video Gateway to be directly connected with circuit switched 3G networks!

A: Using Video Gateway andIntel NetStructure® Signaling Server

39

Circuit switched 3G network using 3G 324m protocol

1. Peter makes a call from a video enabled handset to Maureen’s mobile number (3G 324m call)

2. Multi Media RBT app looks up which

Video / audio clip Maureen has selected

for Peter to see and hear!

3. Peter sees and hears MM RBT

until Maureen answers

SS7G2x Signaling Server with ISUPSS7G2x Signaling Server with ISUP

+ Intelligent Network signaling+ Intelligent Network signaling

Multi Media Ring Back Tones

40

Access WiFi hotspots via SMS commands from mobile phone

WiFi fees are applied to mobile phone bill

End-user benefitsConvenient alternative to using a credit card

Secure method of acquiring WLAN login information – mobile subscriber authentication uses an operator-supplied mobile phone SIM card to ensure only legitimate users access the WLAN

Mobile operator benefitsNew revenue source

Low volumes of access traffic, no new voice traffic is carried

WLAN Authentication

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Base StationSubsystem

Visiting MSC

VLR

1. SMS message is sent requesting hotspot access password

Home MSC

HLR

4. User enters password to access hotspot

Wireless Access Point

EAP Radius802.1x

Authentication Platform

SS7 Link

Wireless Network

IP Connection

5. User is authenticated; records are forwarded to billing servers

3. Authentication platform generates password and sends SMS message back to user’s mobile phone

SMSC

Intel Signaling Server

2. SMSC forwards request to GSM authentication platform

WLAN Authentication Sample Implementation

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LBS locates friends, family members, and co-workers

Growing application in youth and family market segments

Can be permission-based to protect privacy

Location-Based Services: Friend Finder

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Friend Finder Sample Demonstration

Step 1

Step 2

Step 3

Your mobile(9735556789)

Friend’s mobile(9735552456)

Your mobile(9735556789)

Ask your friend to give youpermission to check locationTo ask for permission to check location, just send “add <friend’s mobile number>” to 9085551234.

Your friend sends OK to your request

Your friend can simply send an SMS message “ok <your mobile number>” to 9085551234.

Now you can locate your friendAfter you get permission as above, simply send “find <friend’s mobile number>” to 9085551234.

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Signaling Technology Review

- Hybrid networks developing now

- Hot signaling applications drive revenue growth

- Intel Signaling Solutions meet worldwide customer needs

Questions?

45

Thank You!

[email protected]

Copyright © Intel Corporation 2006.

Intel, Intel Dialogic, Intel NetStructure, Intel Xeon, and the Intel logo are trademarks or registered trademarks of Intel or its subsidiaries in the United States and other countries.

*Other names and brands may be claimed as the property of others.

All rights reserved.

1. Signaling Technology Review

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