Right-Size Your IP-PBX

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October 10-13, 2006• San Diego Convention Center, San Diego California

Right-Size Your IP-PBX

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Agenda

What we will cover

• Define “Right-Sizing”• Telephony Past and

Present• Sample Planning

Methodology• Key Considerations

– 5 - W’s– Architectures

What we will not cover

• Specific Vendor Implementations

• Feature Details• Protocol Wars

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Right-Sizing Defined

• Right-Sizing is the careful planning, consideration and implementation of a VoIP solution that meets current capacity requirements and allows for simplified expansion for future needs while taking into account the necessary endpoint and feature bandwidth requirements.

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Why is this a concern?

• Legacy PBX solutions have fixed capacities based on card-based technology.

In other words, you can’t add more than 16 stations to a 16-port card.

• IP-PBX solutions are not always constrained by port counts on cards so the limiting factor is most often the bandwidth on the connecting link; be it LAN, WAN, WIFI, satellite, or cellular.

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The Past

Each phone plugged directly into the legacy switch. When the card was full, you had to add another card; when the switch was filled to capacity, you bought a new phone system

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Today – Enterprise Wide Scalability

VoIP ManagerVoIP Manager

BranchHubBranchHub

PSTN

PSTN

AnalogAnalogDevicesDevices

(Desktop, Fax, (Desktop, Fax, Conference,Conference,

Modem)Modem)

Facility 1Facility 1


AnalogAnalogDevicesDevices


PSTN


SOHOSOHO

LegacyPBX

Multi-mediaMulti-mediaCommunicationCommunication

DesktopsDesktops

T1/E1/PRI

T1/E1/PRI

Analog FXO Trunks

Analog FXO Trunks

IPIPTelephonesTelephones

(Vmail, Email(Vmail, EmailUnified Messaging)Unified Messaging)

WANWAN

IPIPTelephonesTelephones

IP TelephonesIP Telephones

IP IntegratedIP IntegratedDesktopDesktop

VoiceVoiceMessagingMessaging

MeetingHubMeetingHubCOHubCOHub

Mobile UserMobile User


COHubCOHub

PhoneHubPhoneHub

IP Connectivity (Ethernet or WAN)IP Connectivity (Ethernet or WAN)

Digital Trunks (T1, E1, ISDN PRI)Digital Trunks (T1, E1, ISDN PRI)

Analog Lines (PSTN or Stations)Analog Lines (PSTN or Stations)

* requires private network * requires private network connectivity via, typically via a VPN connectivity via, typically via a VPN connectionconnection

Key: Key:

PSTN

AnalogAnalogFXO GatewaysFXO Gateways

(IP Conference Hub)(IP Conference Hub)

Internet*Internet*

IP WiFiIP WiFiTelephonesTelephones

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Discovery Review Design OrderReview

Adopt a Adopt a Methodology for Methodology for Planning Your Planning Your

Solution for Today, Solution for Today, Tomorrow, and Next Tomorrow, and Next

Year.Year.

Comprehensive Planning

ReviewStage CutoverReview

Planning Methodology (DDOSC)

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Important Planning Considerations

• Ethernet switch type, capacity and manageability.• What are your bandwidth limitations.• How much bandwidth will be allocated to voice.• Is the bandwidth dedicated on a separate physical

network or is it on a logical VLAN• How will you provide Quality of Service (QoS)• Which codecs will be used and where.• Total Number of Endpoints• Additional feature requirements (Video, IM, etc.)• How will the phones receive power? Through a wall

jack at each location or via a Power over Ethernet (PoE) capable switch

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Quick Definitions

QoS – Quality of Service - refers to the probability of the telecommunication network meeting a given traffic contract, or in many cases is used informally to refer to the probability of a packet succeeding in passing between two points in the network within its desired latency period.

vLAN – Virtual LAN - is a method of creating independent logical networks within a physical network. Several VLANs can co-exist within such a network. The advantages of a vLAN are:

• Reduces the broadcast domain, which in turn reduces network traffic and increases network security (both of which are hampered in case of single large broadcast domain)

• Reduces management effort to create subnetworks • Reduces hardware requirement, as networks can be logically instead of physically separated • Increases control over multiple traffic types • Increases network security

PoE – Power over Ethernet - describes a system to transmit electrical power, along with data, to remote devices over standard twisted-pair cable in an Ethernet network. The common standard is known as IEEE 802.3af although some vendors have proprietary power over ethernet technology.

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Codec Defined

• A portmanteau of “coder-decoder” which describes a device or program capable of performing transformations on a data stream or signal.

• Codecs are used to convert an analog voice signal to digitally encoded version. Codecs vary in the sound quality, the bandwidth required, the computational requirements, etc.

• Each service, program, phone, gateway, etc typically supports several different codecs, and when talking to each other, negotiate which codec they will use.

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Common Codecs

• GIPS Family - 13.3 Kbps and up • GSM - 13 Kbps (full rate), 20ms frame size • iLBC - 15Kbps,20ms frame size: 13.3 Kbps, 30ms frame size • ITU G.711 - 64 Kbps, sample-based Also known as Toll Quality • ITU G.722 - 48/56/64 Kbps • ITU G.723.1 - 5.3/6.3 Kbps, 30ms frame size • ITU G.726 - 16/24/32/40 Kbps • ITU G.728 - 16 Kbps • ITU G.729 - 8 Kbps, 10ms frame size • Speex - 2.15 to 44.2 Kbps • LPC10 - 2.5 Kbps • DoD CELP - 4.8 Kbps

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Bandwidth Calculation Considerations

• When calculating bandwidth requirements per call, you must also factor in overhead for the IP and UDP headers.

• For example, G.711 has a bitrate of 64Kbps but a nominal IP bandwidth requirement of 80Kbps per call. The extra 16Kbps per call results from IP overhead.

• Finally, When calculating bandwidth, one can't assume that every channel is used all the time. Normal conversation includes a lot of silence, which often means no packets are sent at all. So even if one voice call sets up two 64 Kbit RTP streams over UDP over IP over Ethernet (which adds overhead), the full bandwidth is not used at all times.

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Other Important Considerations

• When calculating bandwidth requirements and allocations make sure to take into account all variables of the link

– Is it a dedicated link?– How much bandwidth will be allocated to voice?– What other applications are running?– Will you employ silence suppression?

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Why Should You Consider VoIP?

•Your Legacy PBX is obsolete, too costly to service, or out of capacity.

•Continued investment results in a stranded asset, not fully depreciable.

•You have a high concentration of “knowledge” workers that can benefit from the increased productivity realized from “enhanced services”.

•You are rapidly expanding and a converged solution is easier to deploy, maintain and grow.

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Where Should You Implement VoIP?

•Which employees would benefit the most? knowledge workers, executives, call center agents?

•What locations are the best fit? Remote offices, HQ, new offices?

•Which networks are capable? All LAN’s, most LAN’s, WAN connected remote offices?

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When Should You Deploy VoIP?

•What is the appropriate sense of urgency?•Is there an immediate problem that can be solved? •Can you start by “extending the life” of your current system?•How can you leverage this opportunity to begin positioning for your future needs?

•If possible, develop a phased approach over 6, 12, 18 months.

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What Are Your Best Applications for VoIP?

•Should you replace all legacy systems with VoIP?•Can you continue to leverage VoIP to extend the life of your existing system? If so, how will that solution allow you to expand easily and cost effectively.

•Can the VoIP platform start small and easily grow to meet my longer term needs? If so how and at what cost?

•Can you utilize a “best-of-breed” approach to the solution? Phones, Call control, Voicemail from different providers?

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Which Vendor(s) Can Best Meet Your Needs?

•Experienced with Voice applications or Data Applications?

•Open solutions vs Closed solutions?•Multi-Vendor Components vs Single Vendor Components ?

•Application focused vs Network focused?

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IP PBX Deployment Scenarios

Technology EvaluationTechnology Evaluation Proactive IntroductionProactive Introduction Full Scale AdoptionFull Scale AdoptionExploratoryExploratory Cap and GrowCap and Grow GreenfieldGreenfield

• Proactive evaluation of the technology and capabilities.

• Limited reach within the organization initially.

• Controlled roll out.• Minimize capital

expenditures.

• Cap investments in legacy solutions.

• Selective introduce capabilities to targeted users.

• Solve practical business needs.

• Understand the larger picture and potential.

•Lowest Risk•Ensures readiness for the

future•May represent throw away

investment

•Balanced Approach•Manages obsolescence

effectively•Does not realize full

benefits•Expansion may be a

challenge

•Full benefits are realized•Best ROI

•Greatest change•Greatest Risk

• Deploy IP at all new locations.

• Replace legacy systems.• Mandate use of

enhanced services.• Actively pursue

productivity advantages.

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IP PBX Approaches

Extended LifeExtended Life TDM over IPTDM over IP Purpose Built IPPurpose Built IPIP EnabledIP Enabled HybridHybrid Client ServerClient Server

• Ideal for extending the life of a Legacy PBX

• Often used for tie line migration to IP

• Lowers TDM Trunk costs

• Ideal for small scale systems (<100 stations)

• Dependant on embedded call processing modules

• Redundancy is a challenge

• Most scalable approach• Most flexible approach – can also

be used as a legacy PBX migration strategy

• Greatest amount of change

PSTNIP

WAN

IPLAN

LegacyTDM PBXIP

Tru

nks

MediaGateway

PSTNIP

WAN

IPLAN

MediaGateway

TelecomServers

PSTNIP

WAN

IP Trunks

IPStations

TDM Trunks

Telecom ServerAnalogStations

IP LAN

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Evolving VoIP TelecommunicationsAlternative Approaches

Software Centric

Network Agnostic

Open Standards Oriented System

Flat / Distributed Architecture

N + 1 Redundancy

Simple Configuration

Bundled Features

Add-on Upgrades for Expansion

Many Endpoints and Application

Best of Breed Options

Costs Less

Hardware Centric

Proprietary Networks

Proprietary / Closed Systems

Hierarchical / Centralized Architecture

N times 2 Redundancy – if any

Complex Configuration

Expensive Add-on Features

Forklift Upgrades for Expansion

Limited Endpoints & Applications

Single Vendor Solution

Costs More

Hybrid Approach Client Server Approach

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Summary

• Start NOW, even if modestly. The sooner you gain exposure and experience the better. Do not let your organization be caught by surprise.

• Try to anticipate the future. Make sure the solution fits your needs not only today, but tomorrow as well.

• Understand your migration path. Avoid forklift upgrades when you expand.

Right-Size Your IP-PBX

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