evolution of signaling

7/28/2019 Evolution of Signaling

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The Evolution of Signaling

Dan Rothschild

Director, Engineering


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Slide 2

Contents

Signaling Evolution Overview

SS7 Status Sigtran

Bearer Independent Call Control

Converged Networks

NMS Signaling Products


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Slide 3

Signaling Evolution Overview

1990 2000 2007

Bearer Independent Call ControlBICC

Sigtran: SS7/IP

Call Control

Network Services:800, Calling Name, LNP

Wireless: Mobility, Roaming, SMS

IN: Prepaid, Call Mgmt, Ringback

High Speed Links

SS7

Converged Networks

IP Core IMS Multi-Access

SIP H.248 Diameter


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Slide 4

Signaling Evolution Drivers

Signaling bandwidth requirements for new services

SMS, MMS

Number portability

Push-to-talk, voice call continuity

Presence, location

Transport evolution from TDM to packet IP/Ethernet everywhere

Lower cost, higher bandwidth

Protocol explosion in standards bodies

IETF: SIP, SIP-T, SIMPLE, SIGTRAN

3GPP: R99 (UMTS) , R4 (IP-core), R5, R6, R7 (IMS), .


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Slide 5

Signaling Evolution Stages

Starts in core network

Highly utilized routes replaced for bandwidth/cost reduction

Small number of nodes updated/replaced

Sigtran or BICC deployed here first

Evolves to access networks

For new services and/or bandwidth Interworking with new networks

More equipment impacted: switches, gateways, DSLAMs

Migrates to edge devices last

New service deployments

Enhanced service platforms, application servers, mediaservers


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Slide 6

Overview of SS7

Circuit-switched call control: ISUP, TUP

Non-circuit services: TCAP, SCCP IN-service protocols: INAP, AIN, CAMEL

Wireless services: MAP mobility, HLR, roaming, SMS

Network-based services: 800, calling name, LNP

Signaling Transport: MTP layers 1-3Optimized for 48/56/64 kbps links

High-speed links (full T1/E1) introduced for high-bandwidthpaths

Widely deployed in nearly all networks Wireline and wireless

New service deployments still occurring


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Slide 7

SS7 Protocol Architecture

MTP Layer 1

MTP Layer 2

MTP Layer 3

SCCP

IS-634/BSSAP

TCAP

MSC

ANSI-41

HLR

GSMMAP

INAP/CAMEL ISUP/

TUP

BSSService

Node

Transport layers

Upper layers


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Slide 8

SIGTRAN What is it?

Transport of upper layers of SS7 in IP packets

Replaces the transport layers of SS7 (MTP, SCCP)

Sigtran Architecture Components

SCTP Stream Control Transmission Protocol

Reliable transport for signaling

Adaptation Layers many different ones available Resides on both SG and IP Node

Inter-working function on SG

Mapping between IP addresses and SS7 point codes

Multiplexing SS7 interface to multiple IP Nodes

ISUP, TCAP reside on IP Node

(Optional) IPSEC on IP node and SG


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Slide 10

Sigtran Adaptation Layers

One for each different signaling protocol

MTP-2 adaptation layers (M2UA/M2PA)

MTP-3 adaptation layer (M3UA)

SCCP adaptation layer (SUA)

Provides status and network management services

in addition to data transfer Upper adaptation layers support various redundancy

models

Primary/backup

Load sharing


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Slide 11

Packet NetworkPSTN/SS7

PC=10-1-30IP=1.2.3.10STPSTP

SSP

SSP

STPSTP

IP

SCTP

M3UA SUAISUP TCAP

Application

MTP2

MTP3

IP

SCTP

SCCP SUA M3UA

IWF

SGSG

PC=10-1-255

PC=10-1-10

PC=10-1-20

PC=10-1-1

IP=1.2.3.3

IP=1.2.3.2

IP=1.2.3.1MGC

MGC

MGC

Simple Distributed Gateway Architecture


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Slide 12

Current Real World Deployments

AT&T (Cingular) Used M2PA for STP-to-STP hauling of SS7 links

Future plans included: M3UA for MSCs, SMSCs and SCPs

Vodafone Ireland SMSCs

KPN/Netherlands To prepare for IMS infrastructure

China Mobile

SMS traffic again the driver

Just a few examples


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Slide 13

BICC Overview Bearer Independent Call Control

Extension to SS7 ISUP for setting up calls over

packet bearer networks

Can be transported over

SS7 MTP3 or MTP3-b (ATM)

Sigtran M3UA/SCTP

Actual bearer setup protocol can be transportedindependently or tunneled over BICC itself

For RTP/IP bearer networks, SDP can be tunneled over BICCto set up RTP connection

Competes with SIP-T for core network call control


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Slide 14

BICC Capability Sets

Capability set 1 (Q.1901)

Basic call control, ATM-orientation

Forward or Backward Bearer Setup

Codec negotiation + mid-call codec modification

Tear-down bearer at end of call or keep for re-use onanother call

Capability set 2 (Q.1902.x)

IP bearer set-up support

Bearer protocol tunneling

Supplementary services Extension to special resource nodes, via H.248


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Slide 15

BICC Call Setup with tunneled SDP bearer setup

(forward bearer setup)

PSTN-TMCG/MGMGC/MGPSTN-O ISUP

Bearer Established

ISUPBICC

IAM

IAM (connect fwd)

(tunneled SDP Offer)

IAM

ACM

APM (connect fwd)

(tunneled SDP Answer)

APM (connected)

[optional]

ACM

ACM

ANM

ANM

ANM

Note: Many other flows possible


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Slide 16

Gb/IuPS

A/IuCS

SS7

IP/ATM

BTS

BSCMSC Server

VLR

HSSAuC

GMSC server

BSS

SGSN GGSN

CN

C

D

GcGr

Gn Gi

Abis

Gs

B

H

BICC in 3GPP rel5 Architecture:

MSC-Server to MSC-Server Interface (Nc)

2G MS (voice only)

2G+ MS (voice & data)

Node B

RNC

RNS

Iub

3G UE (voice & data)

CS-MGW

CS-MGWNb

PSTN

IuCS

IuPS

IP/ATM

IM

IPPSTN

MGCF

IM-MGW

MRF

CSCF

Mg

Gs

PSTN

McMc

Mc

PSTN

IP Network


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Slide 17

Converged Networks

Packet-switched IP core network (e.g., IMS) Voice, video, data

Common user profile (HSS)

SIP is the dominant signaling protocol

Common services independent of:

Access network Location

Device

Interworking with multiple access networks

Circuit switched and packet switchedWireless, broadband, 2G, 3G, .

Proliferation of protocols can be challenging


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Slide 19

NMS Network Signaling Support

Natural Access

ISDN/CAS

TX 4000TX 4000CTX 4000e

SIPSS7

ISUP BICC TCAP

SigtranM3UA

MTPTDM

VisionSignaling

Server


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Slide 20

SS7 Signaling Boards

TX Series

Support for a full 32 SS7 links and up to 4

high-speed links (HSL) Software-selectable T1 or E1 (120 ohm)

trunks

Full node-level redundancy for highavailability

On-board software, freeing host computer Protocols meet telephony standards,

compatible with all major switches

Variety of form factors and density

Part of the Open Access family

Powerful and flexible solutions for globalSS7 applications

Features

Value Proposition

Benefits

Leverage NMSs worldwide SS7expertise

Scalable hardware with minimum host

loading

Rich and robust API with ITU, ANSIstandards

Competitively-priced, flexible licensing

TX SeriesSignaling

Boards


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Slide 21

Vision Signaling Server

ISUP (ITU and ANSI) signaling for call control

4, 16, or 32 low-speed signaling

links (DS0s) 4 high-speed links (HSL) (DS1s)

Carrier-grade

NEBS-compliant

Redundant, fault tolerant configurations

AC or DC powered

VisionSignaling

Server


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Slide 22

SIP for Natural Access

Uses the Natural Access NCC Service, API

Common programming model simplifies application

development

Supports important extensions for services, such ascall transfer, call hold, and auto attendant

Works with the VoIP service to establish media pathconnections to Natural Access rich mediaprocessing resources

Implemented with RADVISION SIP stack

SIP


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Slide 23

ISDN/CAS

Broad range of TDM signaling protocols

ISDN 11 variants including Euro-ISDN, QSIG ECMA 143, NI-2, Lucent 5ESS

Channel Associated Signaling (CAS)

Worldwide MFC-R2 variants

Many others including CAS R1.5, winkstart, SS5, OPS/OPX,European CAS, digital E&M

Multiple versions of CAS and ISDN can run on a board Selectable during runtime

On-board execution enables efficient call processing whileoffloading the host CPU

PSTNTrunking


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Slide 24

Summary

Signaling network evolution towards converged,SIP-based networks is underway

Transition will take many yearsOperators must leverage existing installed base of SS7

services and equipment

For the next several years, transition technologiesare needed to bridge the gap between todays servicearchitectures and converged networks

NMS signaling products can help smooth the

transition


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Slide 25

Questions?


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