Connecting Your SIP-Based Hosted Contact Center to the Rest of the WorldBrough Turner, SVP & CTO, NMS Communications

3

Communications in Transition

• New services on IP-based platforms– SIP signaling– G.711 “voice” over RTP

• Lower cost

• Easier development

• Faster time-to-market

• Web & IT convergence

Dramatic simplification over PSTN platforms

4

IP-based Services & Systems

• IP call centers, IP PBXs

• Self-service customer voice portals

Financial Services

Travel and Leisure

Telecom / Utilities

Government Retail

• Account balances

• Mortgage refinance screening

• Bank location

• Insurance claim status

• Reservation confirmation

• Theater & Hotel booking

• Service activation / repair

• Prepaid calling card front end

• Service outage info

• Tax info

• Postal information

• Unemployment check status

• International traveler information

• Account balances

• Catalog requests

• Store locator

• Order tracking

• RMA request & status chk

5

Modern Self Service Platform

Follows 3-tier IT architecture

• Database engine

• Business logic– May use application server (dynamic VoiceXML)

• Presentation– Web servers– Media processor (VoiceXML browser)

6

Example Avaya Voice Portal

7

VoIP Adoption

VoIPsubscribers:

38M

Skyperegistrations:

171M

Fixed PSTN: 1.2B Mobile PSTN: 2.7B

8

Connecting to PSTN

• VoIP access to PSTN readily available from major inter-exchange carriers

– Send VoIP traffic almost anywhere in the world– Receive PSTN traffic from anywhere in US

VoIP

IXC

PSTN

IXC Gateway

Databases,Web Services,

Persistent Business logic

SIP

RTP

SpeechResources

VoiceXML ServerWeb Server

http://voiceXML…

IP Telephony

MRCP

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Not so easy in Rest of World

• Problem: inbound traffic, PSTN to VoIP

• Advertise PSTN numbers, receive incoming traffic over IP

• Available as a service in US, parts of the EU, HK, Japan, Australia and Brazil

– Voxbone offering more countries

Expensive or unobtainable in most of the rest of the world

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Nominal Solution

• Provide PSTN gateway with IP-based application

Databases,Web Services,

Persistent Business logic

SIP

RTP

SpeechResources

VoiceXML ServerWeb Server

http://voiceXML…

IP Telephony

MRCP

PSTN

Media Gateway,Signaling Server

& Call Router

Alternately,use IP-PBX and it’s interfaces

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Requirements

• Global deployable: interfaces, approvals

• Cost-effective scaling, including scale down

• Media, signaling & call routing (both ways)

• Highly available at minimum added cost

• SS7 connectivity– SS7 controlled inter-machine trunks can be

significantly less expensive than ISDN

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IP-PBX Approach

• Typically supports ISDN, but not SS7

• Can be expensive to scale up

• Can be expensive to distribute gateway functions to multiple cities

13

Gateway Approach

Solution requires multiple elements

• Media gateway

• Signaling gateway

• Call routing control– Esp. PSTN to SIP routing– Media gateway controller,

softswitch or equiv.

• Example: Cisco AS5300 VoIP Gateway– Requires PGW-2200 Softswitch ($20,000) to

provide basic call routing

14

Integrated Solutions

• NMS Vision Media Gateway and Signaling Server

• Cantata IMG 1010

Characteristics

• Includes call routing

• ISDN, SS7 & Channel Associated Signaling

• Global approvals

• Scalable in 1U/2U increments

• Centralized or distributed deployments

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Basic Installation

SIP-based Services Platform

Switch

• ISDN signaling, or

• Channel-associated signaling (CAS)

SS7

SIP

T1/E1 Voice

RTP

NCC-ISUP

GW

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Small SS7 Configuration

SIP-based Services Platform

SS7

SIP

T1/E1 Voice

RTP

NCC-ISUP

• SS7 signaling

• DACS separates voice and signaling traffic

• Signaling Server separates voice traffic

Switch

SIP-based Services PlatformSwitch

-OR-

DACS

GW

Sig Svr

GW

Sig Svr

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Large SS7 Configuration

. . . . . .

SIP-based Services Platform

• SS7 signaling

• Dedicated T1/E1 Inter-machine trunks (IMTs) for voice traffic

Switch

SS7

SIP

T1/E1 Voice

RTP

NCC-ISUP

GW

GW

GW

Sig Svr

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High Availability

• Media scale by trunks and trunk groups

• N+1 redundancy for media gateways

• Call routing tables (PSTN # to SIP URI) distributed to media gateways

• SS7 signaling 1+1 redundant

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Redundant SS7 Configuration

. . .

SIP-based Services Platform

• SS7 signaling

• Duplicated Signaling Servers for high availability

Switch

SS7

SIP

T1/E1 Voice

RTP

NCC-ISUP

GW

GW

GW

Sig Svr

Sig Svr

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Redundant SS7 Signaling

• 2 servers – 1 point code

• Active-active for MTP1 & MTP2

• Active-standby for MTP3 and above

• Secondary traffic routed to Primary via dedicated Ethernet

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Scalability

• Media Gateway– 8 or 16 E1/T1s per 1U– Mounts in standard racks– Up to 20 Gateways per

Signaling Server (pair)

• Signaling Server– 4, 16, or 32 signaling links– Redundant pair for high

availability

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Other PSTN Issues

• Limited inter-city PSTN capacity in many emerging markets

• Gateway located in capital city means poor service for callers in secondary cities

• Inter-city PSTN calls expensive

• Inter-city IP capacity available and lower cost

SolutionIntegrated IP-based solution with 1U elements

distributed to minimize recurring costs

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Highly Distributed Configuration

• Gateways near switches, signaling servers near STPs

• Decrease networking costs, simplify management

SSP

SSP

SSP

SSP

STP

STP

SIP-based Services Platform

SS7

SIP

T1/E1 Voice

RTP

NCC-ISUP

GW

GW

GW

GW

Sig Svr

Sig Svr

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Conclusions

• Develop new communications applications on IP-based platforms

• Obtain PSTN connectivity from VoIP service providers where available and affordable

• Leverage IP-PBX connectivity when present

• Use integrated gateways for– Global reach– SS7 connectivity– Cost-effective scalability– Cost-effective availability– Flexibility

Questions?

PDF version to be posted todayRecorded version to be posted tomorrow

Brough Turnerrbt @ nmss.com

Blog: http://blogs/nmss.com/communications/