FCC – Office of Engineering and Technology

“Tutorial on Technical Challenges Associated with the Evolution to VoIP”

Presented by:Susan Spradley – President, Wireline Networks Alan Stoddard – General Manager, Carrier Next Generation Networks

FCC Office of Engineering and TechnologySeptember 22, 2003

FCC-OET 9/22/03 -- 2

Agenda

Introduction

IP Telephony Overview

Technical Considerations

Technical Transition Models

Business Transition Models

Conclusions

FCC-OET 9/22/03 -- 3

What is Voice over Internet Protocol (VoIP)?

Public

Internet

“Managed”IP Network

QoS = Best Effort

QoS = Controlled Load orGuaranteed

Voice over the Internet (VOI or VON)

Voice over IPCable

MTA

VideoFeed

CMTS

Data

Wireless Wireline

PublicInternet

FCC-OET 9/22/03 -- 4

BETTY JONES 1:05919-992-1295

Service Drivers

OperationDrivers

Regulation&

Standards

VoiceDataVideo

Telecommunication Network Transitions

Analog to DigitalSS7, CLASS features

Office Consolidation

Clear Regulation/Standards

Digital to PacketMultimedia, Personalization

Network Consolidation

Evolving Regulations

Multiple Forums Driving Standards

AnalogPOTS

Large Offices

One Chief

                                       

Packet conversion, like Digital conversion, driven by Business CasePacket conversion, like Digital conversion, driven by Business Case

FCC-OET 9/22/03 -- 5

VisionConverged Packet Network

IP Network

VideoDataVoice

• Eliminating Boundaries– Geographic independence

– Service flexibility

– Service provider reach

• Data-voice network consolidation

• Central office consolidation

• New service opportunities– Desktop Video

– Application sharing

Revenue generating and Cost Saving OpportunitiesRevenue generating and Cost Saving Opportunities

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Agenda

Introduction

IP Telephony Overview

Technical Considerations

Technical Transition Models

Business Transition Models

Conclusions

FCC-OET 9/22/03 -- 7

VoIP begins with Digital Voice

Digital Switching

In Digital Switching …

… Voice is Data.

AD

A/D Converter

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Digital Circuit Switching

Channels

SingleByte

Time Division Multiplexing

CH0 CH1 CH2 …

EngineeredBandwidth

Time

Cap

acity

WastedBandwidth

Engineering Maintenance

EndOffice

TandemOffice

LDSwiches

Remote Remote

EndOffice

Channels are ReservedNo Voice and Data Integration

Hierarchical Design

High Network Value but … High Network Cost

Used Bandwidth

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Packet Switching

Unified Data and

Voice

EndOffice

Flat Network

No Tandem LayerNo Remote Layer

Time

Cap

acity

DataBandwidth

MaximumBandwidth

Voice and Data Coexist

Remote

• Costs• Maintenance

Engineering Maintenance

Less Equipment

Dynamic Bandwidth Allocation

• Engineering• Utilization

• Value• Utilization

Voice Bandwidth

Unused

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Dynamic Bandwidth Allocation

• Paths Channelized and Grouped• Routes Require pre-Engineered• Unused Channels are Wasted• No prioritization

Value

Packet Link

Data

Unused

Voice

Trunk Group 1

Trunk Group 2

Trunk Group 3

TDM

• All Bandwidth is available• Routes Dynamically Switched• Voice is prioritized• Data fills unused space

Voice alone gains over 30% higher utilizationData and Voice Coexist Efficiently

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ATM Cell Switching vs. IP Routing

Multi-Byte CellsDynamically AllocatedBandwidth ReservedSwitched per Session

Advanced QOS

Synchronous Stream

Cell 0 Cell 1 Cell 2 …

EndOffice

ATM Core

EndOffice

Variable-Byte PacketsNo Native Allocation Scheme

No Native Reservation SchemePackets are Routed Independently

Limited QOSRouters are Unaware of Session

Asynchronous Stream

PayloadHeader

Variable Length Multi-Byte PacketFixed Size Multi-Byte Cells

PayloadHeader

EndOffice

IP Core

EndOffice

FCC-OET 9/22/03 -- 12

Smart IP Routers and Switches

QoS management at different layers

Layer 3 - DiffServ Prioritizes Packet Routing Layer 2 - 802.1 Q/p Prioritizes Ports and Ethernet Frame

- Fragment large packets on Low Speed LinksLayer 1 - Overprovision Bandwidth

CAT 5, Fiber

ETHERNET

ATM, etc.

Interface

CAT 5, Fiber

ETHERNET

ATM, etc.

InterfaceDiffServ

802.1 Q/p

Layer 1

Physical

Layer 2

Data Link

Layer 3

Network

IP

Bandwidth

DiffServ

802.1 Q/p

Layer 1

Physical

Layer 2

Data Link

Layer 3

Network

IP

Bandwidth

DesMac t

SourceMac

802.1 Q Tag

• Priority Bits

• VLAN ID

Protocol

TypePayload

802.1 Q Tag

•Priority Bits

•VLAN ID

Version Header Length

32 Bits 16 Bits 48 Bits48 Bits

First 16 Bits of IP Data Gram

4 Bits 4 Bits 8 Bits

Ethernet Frame

DSCPField (ToS)

DesMac

SourceMac

802.1 Q Tag

• Priority Bits

• VLAN ID

Protocol

TypePayload

802.1 Q Tag

•Priority Bits

•VLAN ID

Version Header Length

32 Bits 16 Bits 48 Bits48 Bits 512 - 12000Bits

First 16 Bits of IP Data Gram

4 Bits 4 Bits 8 Bits

Ethernet Frame

DSCPField (ToS)

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Speech Codecs

G.711: “uncompressed” TDM coding: PSTN standardCompression (reduction in required bit-rate, e.g., G.729)

• Accommodate access link speed (e.g., wireless)• Reduce bandwidth needed in core:

− trade off compression against cost

Concerns• Baseline voice quality will be lower for lower bit-rates• Increased end-to-end delay• Reduced performance with expected packet loss rates• Transcoding

− are there other compression codecs in the network?− how often will multiple transcodings occur in a complicated

path?− frequency of use for features requiring transcoding

conferencing, voice mail

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Agenda

Introduction

IP Telephony Overview

Technical Considerations

Technical Transition Models

Business Transition Models

Conclusions

FCC-OET 9/22/03 -- 15

Application layerNetwork operator wants:A voice quality indicator

Network layer

Manufacturers specify:Delay, link utilization, buffer sizecodecs available packet loss rate

The Voice Quality Problem:How can you know the voice quality is what you want?

Need to establish correspondence between the packet level behavior and the quality perceived at the application level.

Network Engineering Planning Process

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Engineering VoIP

Adjustments to Network

Design

Analysis of Packet Network Impairments Predicted Network Performance

Operational Measurements(Delay, Packet Loss, Jitter)

Network Topology Creator

(access type, equipment, core)

Traffic Profile (loading,

%voice/ %data)

Controllable parameters (voice codec,

packet size, packet loss)

Transport & handoff (IP,ATM, TDM, packet islands, TDM handoff)

Results Analysis & Processing

Implementation

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ReliabilityMaintaining service during network failure events

• Design & Testing: Reliability Before Deployment

─ Reliability Analysis: H/W+S/W Failure rate prediction

─ System and network failure mode analysis

─ Zero Downtime Upgrade and Maintenance by Design

• People & Processes: Responsiveness & Global Support

─ Traffic assurance verification in Large Office test labs

─ Large System Integration Centers in all market environments Asia, NA, SA, Europe, Asia

• Architecture: Engineered for Redundancy & Survivability

─ Self-Healing, Recovers in a Crisis

─ Overload Controls incl. Priority Service to Essential Services

─ Lawful Intercept (CALEA)

"I find that the harder I work, the more luck I seem to have." - Thomas Jefferson

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Control (OAM&P)

Signaling

Bearer/Data Public Network

Voice Network Traffic

Maintaining Security with VoIP

VoIP

Shared Channels

Network Security Hurdles:

• Theft of Service

• Service Disruption

• Privacy– Bearer - eavesdropping– Signaling – collect caller ID / information– Control - theft of subscriber info

Remove Security Hurdles:

• Strong device authentication

• Secure OAM / Encryption

• Strong operator authentication

• Network partitioning & access control

• Voice and signaling accessibility

TDM

Dedicated Channels

Public Network

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Packet Interconnect Between Carriers

Remove Barriers to Cost Reduction with Standardization of:

• Signaling Protocols

• Media Protocols

• Services Delivery

• Packet Interconnect Rules & Billing Agreements

Allow Carriers to Maximize Voice over Packet Architecture Advantages

TDM Office

CallServer

CallServer

PacketNetwork

ISUP

(1) Tandem (2) Local or Tandem

B CA

Packet Bearer Path

Signaling Path

TDM Bearer Path

KeyNetwork 1 Network 2

GW

D

CallServer

CallServer

TDM Office

GWGWGW

Offnet Traffic Between Networks - Significant & Growing Percent of

Total Minutes

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Agenda

Introduction

IP Telephony Overview

Technical Considerations

Technical Transition Models

Business Transition Models

Conclusions

FCC-OET 9/22/03 -- 21

Technical Transition Models

• Transition Models • Enterprise Networks

– IP PBX

– Hosted Services

– VoIP VPNs

• LD Networks• Local Networks • Beyond Voice -- Multimedia Networks

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Transition Models Overlay - Grow all new line and trunks on VoIP, Cap TDM

Evolve - Add IP interfaces to existing TDM infrastructure, new growth on VoIP

Rip & Replace - Replace existing TDM infrastructure with VoIP

Car

rier

E

nter

pris

e

TDM

PBX or Key System

Softswitch

IP PBX

Carrier Hosted VoIP

Hybrid Softswitch

Hybrid IP PBX

Softswitch

IP PBX

Carrier Hosted VoIP

Total Cost - $$ Total Cost - $ Total Cost - $$$

or

+

+

FCC-OET 9/22/03 -- 23

Enterprise Transition IP PBX

Remove Barriers to Profitability• Retail IP Phones provide cost and feature flexibility• Reduced cost IP connectivity to PSTN• Enhanced end user mobility (campus-wide) – increased productivity

Evolve - Hybrid IP PBX• Churn users as needed – growth or

service mobility • Leverage existing CPE

Ovrelay (New) / Replace - IP PBX• New offices or branch sites • Minimize in-building wiring by

using data only connection

Over 25% of the US PBX base expected to be IP-enabled by year end 2005

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•Converged links – local, LD, data•Simple mgmt, efficient b/w use •Improved access for remote users

Enterprise Transition Separate Interconnect to VoIP VPN

•Separate voice & data links •Separate local PSTN & LD connectivity•Complex mgmt, inefficient b/w use

Key System

Sites

PBXSites Centrex

Sites

HQ Site 1

HQ Site 2

VoIP VPNProvider

IP CentrexSites

IP PBXSites

DataProvider

LDProvider

LocalProvider

IP CentrexSites

Key SystemSites

IP PBXSites

PBXSites Centrex

Sites

HQ Site 1

HQ Site 2

Remove Barriers to Outsourced Private Networking Drive New Carrier Revenue / Customer Retention

FCC-OET 9/22/03 -- 25

Enterprise Transition Hosted VoIP (IP Centrex)

Remove Barriers to Outsourced Voice – Save up to 35% over IP PBX• Retail IP Phones provide cost and feature flexibility• Outsource but retain control with improved end user management tools

and simplified moves, add, changes • Avoid Long Distance charges • Enhanced user mobility and feature transparency – campus-wide, at

home, remote offices, on the road – for improved productivity

Drive High Margin Carrier Revenue Stream - Differentiated Service Bundle

Evolve – Hybrid IP Centrex • Churn users as needed – growth or

service mobility • Leverage existing CPE

Overlay (New) / Replace - IP Centrex• New offices or branch sites • Minimize in-building wiring by

using data only connection

FCC-OET 9/22/03 -- 26

Long Distance Transition

Remove Barriers to Carrier Expansion & Service Introduction • Improved Capacity - Relieves CPU Exhaust• Fewer Trunk Groups, Muxes, X-Connects & Simplified Trunk Rearrangement• 15-25% Reduction of Interconnect Ports between Switches• Ability to Address New Markets at Low Cost

Provide up to 20% Carrier Cash Flow Improvement and Packet Infrastructure to Speed IP Services Delivery

Overlay • Add additional switching nodes • Groom trunks to new VoIP nodes • Interconnect inefficiencies

between TDM and VoIP

Evolve / Replace • Convert or replace existing nodes • Delay additional switching nodes

for later growth • Limit operational expense

VoIP VoIP

FCC-OET 9/22/03 -- 27

Local Network Transition

Remove Barriers to Carrier Expansion & Service Introduction• Eliminate Tandems, X-Connects, Trunking between Switch Nodes• Reduce Switch Nodes by 50-85%, Equipment by 60-80%, B/W use up to 30%• Expand Out of Territory at Low Cost • Retain / Grow Centrex - National Centrex, Centrex IP, Churn PBX to Hosted IP

Provide 10-20% Carrier Cash Flow Improvement and Packet Infrastructure to Speed IP Services Delivery

Overlay • Add additional switching nodes • Groom trunks to new VoIP nodes • Interconnect inefficiencies

between TDM and VoIP

Evolve / Replace • Convert or replace existing nodes • Delay additional switching nodes

for later growth • Limit operational expense

VoIP VoIP

FCC-OET 9/22/03 -- 28

Beyond Voice – Multimedia Transition

Evolve - Converged Desktop •Traditional voice services maintained with new multimedia add-ons

•Existing desktop retained - new phone upgrades at end user driven pace

•Utilizes existing TDM SIMRING or IN•Enables ubiquitous service delivery

Multimedia Existing Phone

Remove Barriers to New Service Introduction•Simplify communications – Personal Communications Mgr, Unified Messaging •Enhance productivity – Video Calling & Conferencing, Web-Push / Co-Browsing

Provide New Carrier Revenue Stream & Differentiate Service Set

Overlay (New) / Replace • IP phone required •Softclient flexibility – PDAs and PCs become phones

•Voice becomes a subset of data services bundle – delivered over DSL or data connection

FCC-OET 9/22/03 -- 29

Agenda

Introduction

IP Telephony Overview

Technical Considerations

Technical Transition Models

Business Transition Models

Conclusions

FCC-OET 9/22/03 -- 30

Business TransitionNetwork separate from Service

Separating Service & Network permits Service ubiquity independent of accessSeparating Service & Network permits Service ubiquity independent of access

Network Transition• Competitive Local: Cable, W-, CLEC

– Cities/Municipalities?

• More Competitive LD: IXC vs LEC• Data Access:

– Res: DSL vs Cable– Biz: LEC vs IXC

• Emerging Acccess Implications?– Wireless LANs – Fiber to the Home (FTTH)

Services Transition• Voice: LECs to Cable, W-,

CLEC• Video: Cable Broadband • IM: Yahoo, AOL to ASP• Client Based Services

– SIP Clients– Peer to Peer– Napster Model

• Service Provider Based Service– Yahoo, AOL, Microsoft, Apple– Business specific Companies– Bring your own broadband

FCC-OET 9/22/03 -- 31

Business TransitionTransition Squabble, Struggle, Brouhaha

Market will determine Niche vs End-to-End providersMarket will determine Niche vs End-to-End providers

Cable Co’s

LECs

WirelessCarriers

IXCs CLECs

Yahoo/AOL/MSN

Apple/Microsoft

Industry Specific(e.g. Banks, Gaming,

Brokerage..)Cities/Municipalities

Network/Access• Competitive Carriers: Cable, ISPs

• International Carriers: AT&T

• Data Carriers: UUNET– Res: DSL vs Cable– Biz: LEC vs IXC

• Implication of Wireless LANs, Hot spots

Services•IM: Yahoo, AOL to ASP

•Voice: LECs to Cable, W-, CLEC

•Video: Cable Broadband

•Next Gen: Yahoo, AOL, Microsoft, LECs, IXCs, etc.

FCC-OET 9/22/03 -- 32

Business TransitionNew Models

Regulation will impact viability of new Business ModelsRegulation will impact viability of new Business Models

Client Based Services• Peer-to-Peer• Web/Napster• Pre-arranged Address exchange• SIP based clients

Network Based Services• Network operators provide Service based on

Access (Network + Services)• Partnerships: Yahoo/SBC - MSN/Verizon• Mergers?• Can drive Uniformity/Ubiquity

Providers move with customer to new Business ModelsProviders move with customer to new Business Models

Service Provider Based Services• ISPs offer ad hoc, interpersonal

communications brokerage• Bring your own broadband• Fwd.pulver.com, IM, Email• Reliability required?

Wiretap required?

FCC-OET 9/22/03 -- 33

Agenda

Introduction

IP Telephony Overview

Technical Considerations

Technical Transition Models

Business Transition Models

Conclusions

FCC-OET 9/22/03 -- 34

Conclusions

• Technology is decoupling Service from Access

• Users desire ubiquitous service access, personalization and the freedom of mobility

• There are technology challenges that need to be considered in developing and deploying IP Telephony

• There are both technical transition and business transition models to consider