Lync for Dummies

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By Mohan Palat and Kevin Isacks

Lync

EnterpriseVoice

Sonus Special Edition

These materials are the copyright of John Wiley & Sons, Inc. and anydissemination, distribution, or unauthorized use is strictly prohibited.


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LyncEnterprise Voice For Dummies, Sonus Special Edition

Published byJohn Wiley & Sons, Inc.

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Table of ContentsIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

About This Book ........................................................................ 1Icons Used In This Book ............................................................ 2

Chapter 1: Taking a Peek atUnified Communications . . . . . . . . . . . . . . . . . . . . . . . . . 3

Understanding UC ...................................................................... 4Looking at UC Applications ...................................................... 5So, Where Does UC Come From? ............................................. 6

Chapter 2: Getting Acquaintedwith Microsoft Lync . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

What Is Lync All About Anyway? ............................................. 7Understanding Lync Servers and Apps ................................... 8

Microsoft Lync Server ..................................................... 8Microsoft Lync App ......................................................... 9

Understanding Your Optionsfor Lync Server Deployment ............................................... 10

Deploying Lync on-premises ........................................ 10Using hosted Lync services .......................................... 11Hybrid Lync services..................................................... 12Choosing between the three options .......................... 12

Applications Enabled by Lync ................................................ 13Understanding Why Enterprises Choose Lync .................... 14

Chapter 3: Digging into Lync Enterprise Voice . . . . . . .15

What is Lync Enterprise Voice? ............................................. 16Looking into Lync Enterprise voice features ............. 16Making Lync Enterprise Voice work............................ 17Planning for deployment .............................................. 18Different deployment models ....................................... 18

Choosing a deployment model .................................... 19Reviewing a Lync Enterprise Voice Case Study ................... 21



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Lync Enterprise Voice For Dummies, Sonus Special Editioniv

Chapter 4: Getting the Most Outof Lync Enterprise Voice. . . . . . . . . . . . . . . . . . . . . . . . 23

IP-PBX/Gateways ...................................................................... 23Making Enterprise Voice More Robust

with Survivability ................................................................. 25Understanding SBAs................................................................ 26Introducing the SBC ................................................................. 28

Chapter 5: Leveraging SBC for Enterprise Voice . . . . . .31

Connecting to SIP Trunking Services .................................... 32

Integrating with Existing IP-PBX Platforms ........................... 33Ensuring QoS ............................................................................ 34Supporting E911 ....................................................................... 35Dealing with Interoperability between Vendors .................. 36Centralizing Control and Troubleshooting ........................... 36

Chapter 6: Ten Reasons to Choose Sonus whenDeploying Lync for Enterprise Voice . . . . . . . . . . . . . .39

Microsoft Compatibility and Qualification ........................... 39Proven Experience................................................................... 39Multivendor Interoperability .................................................. 40Maximized Resiliency and Protection

Against DoS Attacks ............................................................. 40Encrypted Communications ................................................... 40Rapid Recovery ........................................................................ 41Survivability for Branch Sites ................................................. 41Centralized Policy Management............................................. 42

Exceptional Transcoding Performance ................................. 42Wide-Ranging Media Support ................................................. 42



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ForewordFor many organizations, the search for the next technology todeliver strategic advantages is leading to Unified Communi-cations (UC) and to Microsoft Lync as a critical component.Lync delivers a unique set of capabilities to integrate commu-nication modalities, presence, application integration, andother services. Organizations can streamline business pro-cesses and increase productivity by assuring that the rightcommunications happen at the right time, with the right

people, and the right tools. Most Lync deployments start as aninternal trial and then deploy, but extending Lync beyond theboundaries of the organization can yield equal or even greaterbenefits than internal use alone. By using Lync federation,capabilities can be extended to partners and customers,reducing costs and increasing business success. Using Lyncconferencing can reduce conferencing costs and, when com-bined with Lync telephony services, can deliver a truly unifieduser experience. You may also experience a reduced cost with

traditional legacy telephony equipment.However, when Lync is extended beyond the organizationboundaries issues of interoperation, security, control, andmanagement emerge. Organizations contemplating Lyncdeployment should begin planning for external Lync capabili-ties. Even if the initial deployment is internal, often users anddepartments will drive rapidly for external Lync capabilities,so make sure you plan ahead.

One key element of a successful external Lync deployment is aSession Border Controller (SBC) that can manage and assurethe security and integrity of the organization. Lync externaliza-tion opens doors to new sets of threats that can have signifi-cant impact. This book guides you to understand the issuesand complexity of a Lync Enterprise Voice deployment. It givesthe reader the initial tools to begin to make the right decisionto assure personal, solution, and organization success withLync Voice.

Phil EdholmPKE Consulting LLC & UCStrategies.com

[email protected]

www.pkeconsulting.com



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IntroductionE

nterprises of all sizes and kinds (government, private,education, and so on) have begun to fully adopt and

embrace the latest in Voice over Internet Protocol (VoIP)technologies. VoIP enables Unified Communications (UC) that

bring all sorts of different VoIP-enabled services together sothey work together seamlessly and in a (well, weve got to sayit) unified way.

With UC, an enterprise user can use a single software applica-tion (app) on his desktop, laptop, tablet, or smartphone tocommunicate and collaborate with colleagues, customers, andpartners through instant messaging, voice calls, conferencecalls, videoconferences, screen and application sharing, and

more. If youve not used it before, well, its awesome.

About This BookOne of the leading software platforms for UC is MicrosoftsLync. In this book, we talk about Lync and give you an ideajust what its all about and what kinds of UC services Lyncsupports. Most importantly, we introduce you to LyncEnterprise Voice an additional element of Microsoft Lyncthat enables the Lync platform to completely replace a tradi-tional enterprise Private Branch Exchange (PBX). (In case youdidnt know, a PBX is the business phone system that mostenterprises use to enable things like call transfers, call hold-ing, conference calling, and more).

While Lync by itself can bring a lot of productivity benefitsto an enterprise and make for happier employees who cancollaborate and communicate in new ways, adding LyncEnterprise Voice to the mix also provides a way for enter-prises to offer their employees really cool voice, video, andcollaboration services while also saving a boatload of money(compared to traditional PBX and phone services).



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Lync Enterprise Voice For Dummies, Sonus Special Edition2

Is your enterprise thinking about implementing UC? Or haveyou already got a Lync deployment and youre now consider-

ing going for the big cost savings with Lync Enterprise Voice?Or are you a service provider who wants to offer these ser-vices to your customers? If so, thenLync Enterprise Voice For

Dummies,Sonus Special Edition, is the book for you.

Icons Used In This BookThis book calls out important bits of information with iconson the left margins of the page. Youll find four such icons:

The Tip icon points out a bit of information that aids in yourunderstanding of a topic or provides a little bit of extra infor-mation that may save you time, money, and a headache.

Pay attention to the Remember icon because it points outparts of the text to lock away in your memory for future use.

Watch out! This information tells you to steer clear of thingsthat may cost you big bucks, suck your time, or be badpractices.

We try to keep the technical jargon and discussion to a mini-mum. You wont need to know these factoids to get the mostout of the book, but you may find them interesting.



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Chapter 1

Taking a Peek at UnifiedCommunications

In This Chapter Getting a handle on UC

Understanding the world of UC applications

Learning who provides UC

For many years, companies, large and small, have reliedon Private Branch Exchange (PBX) systems for their

voice telephony needs. PBXs provide business phone fea-tures, such as shorter numbers for internal dialing, calltransfers, and bridging conference calls. The rise of Internettechnologies like Voice over Internet Protocol (VoIP) hasdriven businesses to switch to Unified Communications (UC)from their old PBX systems for voice telephony.

A leading solution for UC is Microsoft Lync, which, with itsEnterprise Voice components, offers a full replacement for atraditional PBX service. In order to create a robust and high-quality UC voice service for an enterprise with Lync, you alsoneed a special device called the Session Border Controller(SBC), and you need to buy a Session Initiation Protocol (SIP)Trunking service from your Internet Service Provider (ISP).Figure 1-1 shows you how this all fits together.



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Figure 1-1:The Microsoft Lync Enterprise Voice solution.

Understanding UCUC is the next evolution in enterprise communications andcollaboration technologies, bringing all varied connectionsunder a single architecture. This process makes communica-tion seamless, no matter where you are or what device you use.These communications can be delivered over an IP (Internetprotocol) network through the following mechanisms:

Voice:Calls, voice mails, multi-party conference calls,and so on

Video:Videoconferences, on-demand video learning, andso on

Data:Text messaging, e-mail, document sharing, and so on

The unifiedpart of UC refers to the fact that the UC hardware

and software take all these communication applications andput them under the purview of a common control systeminstead of using different hardware and software solutions foreach individual application.

Doing so provides two big benefits:

It allows communications to be delivered across media.For example, a voice mail left by one employee may be

delivered to its recipient as an e-mail attachment or evenas a speech-to-text translated message.

It applies presence and location information to the com-munications flow so communications are routed anddelivered intelligently.



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Chapter 1: Taking a Peek at Unified Communications 5

Presencesimply means the ability and willingness of an indi-vidual to receive certain types of communications. If youve

ever used Skype or an instant messaging program, yourstatus (available, busy, do not disturb) is your presence.

In UC, presence is a richer bit of data and when com-bined with location helps the UC system figure out howand when to deliver your communications to you. Forexample, if youre out of the office and at a meeting, a UCsystem may route calls to your mobile device and alsonot even try to ring the phone.

This combination of multiple platform, client, and communi-cation methods with presence and location data is a powerfultool one that can greatly streamline and improve the waysthat enterprise employees communicate, coordinate, and col-laborate with each other, whether theyre in a single locationor spread across the globe. Say goodbye to playing phone tagand endless e-mails or voice mails, and say hello to UC!

Looking at UC ApplicationsThe most common UC applications include the following:

Voice calls:UC systems provide VoIP-based person-to-person or multiparty voice communications, by usingsoftware applications (apps) on PCs or Macs or onmobile and tablet devices. With a UC system, users no

longer need a PBX system to make voice or even videocalls to others. Users also save a lot of money in voicecalls by skipping the traditional public telephone net-work and using VoIP instead.

Instant messaging (IM):UC systems provide person-to-person or multiparty IM (like AOL IM or Skype),often with the addition of features like persistent chatsessions, the ability for an IM session to pass betweendevices, and for a user to pick up a chat where he left off.

Videoconferencing: UC supports high-quality (often HD)videoconferencing. These calls can be person-to-personor, depending on the system, between groups of people.

Collaboration and meetings:Conferencing and collabo-ration are key parts of a UC solution for enterprise. Thereare a number of aspects to conferencing, including IM/chat, voice, and video.



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Dont limit your UC apps to the desktop. UC platforms cansupport mobile devices as fully integrated clients. To make

this work, you need a working data connection on the mobiledevice and a UC app installed on the device by the IT depart-ment or through an app store.

So, Where Does UC Come From?What you need to deploy UC in your enterprise (or to provideit to your customers if youre a service provider) includes afew key elements:

Connectivity to an IP network, usually including SIPTrunking services

A server (or servers) to run the UC applications and pro-vide back-end functionality, such as directory or contactservers, presence data, and so on

UC clients on the end-user devices (desktop or mobile)

Edge devices (like an SBC) to control, secure, and opti-mize connections to the network

UC can be deployed in a combination of ways:

Enterprise deployments:Choose to deploy the serversand software within your own datacenter or server roomand own and operate the UC system itself.

Hosted deployments: Access UC in the cloud by pur-chasing access to a hosted UC service. In this case, athird-party service provider manages for all the servers,software, and operations the enterprise just paysto use.

Hybrid deployments:Some functionality is installedon the enterprise premise while other functionality ishosted in the cloud by a service provider.

Whether an enterprise deploys UC on its own or through ahosted service, it still requires connectivity through a SIPTrunking service provider or Internet Telephony ServiceProvider (ITSP). The ITSP provides bandwidth and connectiv-ity and (in most cases) connectivity to the Public SwitchedTelephone Network (PSTN).



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Chapter 2

Getting Acquaintedwith Microsoft Lync

In This Chapter Introducing Microsoft Lync

Meeting the servers and clients

Learning about Lync deployment scenarios

Taking stock of Lync applications

Understanding the benefits of Lync

Enterprises of all sizes and kinds are adopting UnifiedCommunications (UC). (Check out Chapter 1 if youre

not sure what UC is all about.) And one of the most widelydeployed UC solutions comes from the folks in Redmond,Washington: Microsoft Lync.

In this chapter, we introduce you to Microsoft Lync and talkabout the servers and clients required to deploy Lync in anenterprise. Next, we discuss the different deployment scenar-ios and the applications that Lync enables. You also discoverthe reasons why so many enterprises are deploying Lync.

What Is Lync AllAbout Anyway?Microsoft has been investing in and developing applicationsfor communications and collaboration for a long time. Lync isthe latest and greatest and far more advanced evolutionin the long line of products.



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For more information on what Microsoft has to say about theLync product, visit office.microsoft.com/en-us/lync.

Microsoft Lync is an enterprise-ready UC platform. UCrequires two elements:

A UC server running the UC software platform in thedatacenter (which could be inside the enterprise orhosted by a third party)

UC software running on the end-users PC, phone,or tablet

Lync provides both the server software (hosted by your owndatacenter or by Microsoft itself) and the app software forvarious platforms to enable a robust voice, video, and dataUC solution appropriate for any enterprise. Because its aunifiedplatform (it is UC, after all), Lync supports all the UCapplications using a single-server platform and a single appli-cation, meaning theres less to learn, less to deploy, and lessto manage.

Understanding LyncServers and Apps

Microsoft Lync has two major elements: Microsoft LyncServer and Microsoft Lync Server App (the client software).

Microsoft Lync ServerMicrosoft Lync Server is designed to provide the followingservices to an enterprise:

Instant Messaging (IM) and presence: Existsboth withinthe enterprise and outside of it. It can also talk to other

standard Internet IM systems, such as Windows Live,Yahoo! Messenger, AOL IM, and Google Talk.

Conferencing:Gives you the ability to videoconferenceand allows users to share screens and applications, enjoycollaboration, manage voice and chat (IM) meetings, and



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Chapter 2: Getting Acquainted with Microsoft Lync 9

conduct virtual meetings anytime, anywhere, and on anydevice (including mobile).

Enterprise voice:VoIP support for person-to-person andmultipoint audio calls, including standard Private BranchExchange (PBX), which is an enterprise telephone systemfunctionality such as voice mail, call holding, forwarding,and so on.

Connection to the PSTN (Private Switched TelephoneNetwork) or SIP (Session Initiation Protocol) Trunking:Supports calling outside of the enterprise network via

connection to either a traditional phone company or toan Internet Service Provider (ISP) that offers voice ser-vices via a SIP Trunking connection.

Support for remote and mobile users: Fully supportsremote and branch office users, telecommuters, andmobile workers.

Many other functions arent mentioned in this list Lyncliterally supports dozens of apps and services (you can findan exhaustive, too-long-to-print list on Microsofts website).

Lync Server utilizes the SIP protocol as the underlying pro-tocol for routing and controlling communications within theenterprise network and beyond. SIP is a standardized proto-col used for supporting voice, video, and conferencing overcommon Internet Protocol (IP) networks. Using SIP ensuresthat the services enabled by Lync Server are broadly compat-ible across devices, networks, and with other UC and commu-nications systems.

You have some options for deploying Lync Server for anenterprise. We cover these in more detail in the sectionUnderstanding Your Options for Lync Server Deploymentlater in the chapter.

Microsoft Lync AppBeyond the server (see the preceding section), a Lync deploy-ment requires apps on the devices and endpoints (also calledLync Client) where enterprises employees actually interfacewith their Lync services. As a Lync client, you have a fewoptions for using Microsoft Lync App:



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Microsoft Lync software: This is the primary way thatmost of you will use Lync. The Microsoft Lync client soft-

ware supports all Lync functionality through one stopshopping users can rely on a single app on their PCsfor IM, to set their presence preferences for video andvoice calls, and for collaborative conferencing.

For claritys sake, well always use the word clientwhen were discussing the client software.

Web client:Users arent required to have the client soft-ware on their computer to use Lync. Lync supports full-

featured client access via a Web browser interface. Allthats needed is an HTML 5 compliant browser (meaningthe latest versions of Internet Explorer, Safari, Chrome, orMozilla) on a PC or Macintosh laptop or desktop computer.

Mobile clients app:Microsoft has developed mobileLync apps for Windows Mobile, Android, and iOS devices(both iPhone and iPad). So users can access their Lyncservices on the go wherever they are.

Lync-enabled phones:Not everyone wants to talkthrough a PC or tablet (or even a mobile device) all thetime. With that in mind, Microsoft has certified a numberof phones and related devices that serve in a Lync UCnetwork.

You can find an up-to-date list of devices that are opti-mized for Lync at technet.microsoft.com/en-us/lync/gg278164.aspx.

Understanding Your Optionsfor Lync Server Deployment

The Lync Server is installed on-premises in an Internet(hosted) datacenter or through a hybrid solution.

Deploying Lync on-premisesThe first Lync option is for an enterprise to install and hostthe Lync Server software itself in its own datacenter. There



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are few types of servers that may be installed in an on-prem-ises deployment of Lync Server.

All the following server types can be deployed within a single-server computer or across a pool of two or more server com-puters for greater redundancy, reliability, and capacity:

Front-end and back-end servers:These are the basic,must-have servers for any Lync deployment. The front-end server (or servers, in a larger deployment) handlesuser authentication, presence information, contact and

address book functionality, and the delivery of applica-tions. The back-end server hosts the databases to makethe front-end servers work.

There is also a LyncStandard Edition Serverfor smallerenterprise deployments (and for pilot deploymentswithin larger organizations). This combines the front- andback-end servers within a single device, but it loses theredundancy and high availability of a distributed serversolution, so it isnt recommended for mission-criticallarger deployments.

Edge servers:For enterprises offering Lync services tomobile or remote users (branch offices, telecommuters,road warriors), an edge server, located in the DMZ out-sideof the corporate firewall, is required.

Mediation server:For deployments of Lync that replacea traditional PBX service with Lync Enterprise Voice, themediation server handles all the signaling, translation,and other media routing and handling roles. This servercan be on the same hardware as the front-end server oron its own server computer.

Other servers:Optionally, additional server types maybe required, based on the range of services, scale, andcomplexity of a given deployment.

Using hosted Lync servicesNot every enterprise wants to or has the capability to install, manage, and maintain an in-house Lync deployment.For those, Microsoft offers the option to use hosted, cloud-basedLync Onlineservices.



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Lync Online is simply Lync delivered as a hosted serviceover the enterprises Internet connection. That means that

someone else (Microsoft or another third party) owns andruns the Lync servers in its own datacenter and the enterpriseaccesses them via a data connection.

Although it supports voice, Lync Online is not a full replace-ment for an enterprises existing PBX platform.

Hybrid Lync servicesYou can also deploy Lync in an enterprise via the hybridoption, which is a service between on-premise and hosted.In a hybrid deployment, an enterprise can move some func-tionality to the Lync Online service while maintaining otherfunctionality within on-premise servers. Specifically, a hybriddeployment may be used to

Deploy Lync Enterprise Voice on-premises while utilizing

Lync Online for other services (this is calledHybrid Voice) Maintain existing PBX voice services while utilizing Lync

Online for other UC services like IM and conferencing

Gradually migrate from an on-premise to a hosted Lyncdeployment

Choosing betweenthe three optionsWhich of the options should an enterprise choose? Well, theprimary decision point is what priority Enterprise Voice orPBX-like services hold to the enterprise if theyre part ofthe goals of a Lync deployment, then the on-premise or hybridapproach is required. If an enterprise is mainly concernedwith IM and conferencing functionality, Lync Online will dojust fine.



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Applications Enabled by LyncThe services enabled by a Lync deployment include

Telephony: With Lync Enterprise Voice, Lync can be acomplete replacement for an enterprises existing PBXsystem. Users can call within the enterprise or (througha SIP Trunk or PSTN interface) anywhere in the world.Lync supports all the PBX functionality that enterprisesexpect, including conferencing, call forwarding and trans-

fer, voice mail, and more. With SIP Trunking present,Lync Enterprise Voice can save an enterprise significantmoney compared to traditional PBX voice.

IM and presence:Using their Lync clients on PC ormobile devices, users can set their presence and engagein real-time and persistent IM chat sessions with one ormany users at a time. If their Lync deployment is config-ured, they can chat with Lync users in other enterprisesor use standard Internet IM protocols to chat with users

anywhere on the Web.

Video conferencing:Users can conduct HD-quality vid-eoconferences with up to five users at a time to conductvirtual meetings anytime and anywhere and on anydevice (including mobile).

Lync meetings:Beyond video, Lync users can quickly(with one click in most cases) conduct collaborativemeetings, including screen sharing, PowerPoint sharing,

and other application sharing. Users outside of the enter-prise (clients and partners) can be included by using asimple URL and the Lync Web client.

Whats new in Lync 2013Microsoft is adding a number of com-pelling new features in Lync 2013including the following:

Support for Enterprise Voice(discussed in Chapter 3) in thehybrid deployment model

Enhanced E911 support

New and improved client appli-cations for Windows 8, WindowsPhone, iOS, Android, and webbrowsers

(continued)



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Understanding Why EnterprisesChoose Lync

Millions of users are currently using Lync within theirenterprises traditionally the IM, presence, and collabora-tion features have drawn enterprises into the world of Lync.But voice is becoming an increasingly important part of Lyncdeployments Lync deployment consultancies have recentlystated that over 50 percent of their new business includesEnterprise Voice. With the support for hybrid enterprise voicein Lync 2013, this number is bound to go up.

Whats driving this adoption? Several things:

Lync offers integration with existing, incumbentMicrosoft services, such as Outlook, and uses familiarserver platforms (Microsoft Server and SQL).

Lync supports a wide range of compatible clients across PCs, Macs (with Web client), and all the mostpopular smartphone and tablet platforms.

Lyncs focus on security is a major plus for many enter-prises. We talk more about security in Chapters 4, 5, and 6.

Lync offers broad compatibility, such as support forthird-party network hardware and third-party IM andconferencing applications such as Skype.

Improved call management androuting features

1080p (high definition) videocon-ferencing support including callsof up to five people

Updated web application sup-port, providing better access toLync apps via the Web

Greater scalability

Improved management tools

The ability to integrate Skypeusers into the contact list, seetheir presence information, andcommunicate with them

Support for Microsoft OfficeOneNote, so a user can sharea OneNote document during aLync meeting

(continued)



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Chapter 3

Digging into LyncEnterprise Voice

In This Chapter Getting to know Lync Enterprise Voice

Seeing Lync Enterprise Voice in action

Enterprise voice provides a business with all the func-tionality that used to require a Private Branch Exchange

(PBX). That functionality includes conference calling, desk-to-desk calling, hold music, attendant functionalities, and more.Microsoft Lync Enterprise Voice is the implementation ofenterprise voice for businesses by using the Microsoft LyncUC platform. With Lync, enterprises can segue from a legacyPBX solution(s) at their own pace.

The most basic implementations of Microsoft Lync UnifiedCommunications (UC) provide an enterprises users with IM,presence and the ability to conduct meetings via voice, video,and collaboration software. The most basic Lync deployments,however, dont offer all the voice communications stuff thatshandled by business PBX systems. So whats the end result?Communications are still siloed in two distinct systems: onefor users who use Lync and another for those who use thePBX (most often through their desk phones). But, with the

addition of Lync Enterprise Voice particularly the latestversion of Lync, Lync 2013 that no longer needs to be thecase. Lync Enterprise Voice provides an overarching architec-ture for allof an enterprises communications, making themtruly unified.



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What is Lync Enterprise Voice?Any Lync deployment gives you voice. You can use an in-house or hosted Lync server and a Lync client to make voicecalls to other users within an enterprise, to other Lync usersor partners, or even beyond that with web clients and Skypeintegration. But voice isnt Lync Enterprise Voice. Its merelya subset.

Think of the difference in terms of comparing a VoIP-enabled

IM client running on your home PC with a phone serviceoffered by your telco or cable company. Both let you talk tosomeone, but only the latter is set up to provide 911 calls(with location data) and to allow more sophisticated callingfeatures like call forwarding, hold, transfer, and so on.

What Lync Enterprise Voice does, in a nutshell, is bring thefull-fledged enterprise PBX experience under the umbrellaof Lync UC. An enterprise can use Lync Enterprise Voice to

supplement or even replace an Internet Protocol PBX (IP-PBX)system.

Looking into Lync Enterprisevoice featuresEssentially offering everything that an enterprise may use anIP-PBX or traditional PBX to provide, Lync Enterprise Voiceenables a wide range of enterprise telephony features:

Connectivity to the PSTN:Lync users can call anynumber, anywhere (within the policy limits of theenterprise of course no calls to Antarctica!) throughconnectivity to the PSTN via a gateway or SIP Trunkingconnection (more on these in Chapter 4).

Voice calls from anywhere:Use Lync to place and

receive calls from any device, in any location, throughthe Lync client.

Device switching:Use Lync to switch devices (for exam-ple, from a headset on your PC to a conference roomphone) with no interruption. This is often known ascall parking.



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Chapter 3: Digging into Lync Enterprise Voice 17

Call handling: You can forward calls or send them tovoice mail or to your mobile phone all without drop-

ping the call. Simultaneous ring:Incoming calls can ring on any or

allyour devices, so calls are never missed (except onpurpose, of course!).

Team calling and delegation:Configure calls to ring onthe phones or devices of all members of a team or todelegate calls to an assistant.

Common area phones/hot-desking:Calls ring through tophones that arent associated with an individual user, soyou can get your calls in the conference room or at thedesk you choose today.

Caller ID manipulation:You use a different outboundcaller ID (for example, showing the main number for anenterprise location rather than an individuals).

E911:Provides location information on calls to emer-gency services (911).

Making Lync EnterpriseVoice workSome additional hardware, server, and software requirementsexist to enable Lync Enterprise Voice. At a high level, youregoing to need the following:

A Lync mediation server (discussed in Chapter 2 not arequirement for basic Lync deployments but required forLync Enterprise Voice)

A device or service to connect your Lync UC network tothe PSTN (more on this in the section Different deploy-ment models a little bit later in the chapter)

Additional servers based on the applications youre

deploying, the number of users, and the desired redun-dancy and survivability of the network



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Planning for deploymentIn order to successfully deploy Lync Enterprise Voice, yourtechnical team needs to spend time actually planning thedeployment in terms of the policies and configurations thatgovern your deployment and the underlying network facilitiesthat your Lync Enterprise Voice deployment requires.

Download the Microsoft Lync Planning Tool applicationfrom Microsoft before you start designing and planning aLync Enterprise Voice deployment. This software walks youthrough your actual deployment and gives you a detailed listof server and software requirements as well as a proposednetwork diagram to support the deployment. The Lync Serversoftware itself contains a Topology Builder module which when the actual deployment begins will validate the net-work deployment as part of the installation process.

When you plan your Lync Enterprise Voice deployment, con-sider the following factors:

Figure out the number and types of sites you want todeploy. Lync Enterprise Voice deployment contains twotypes of sites:

Central sites:Major offices where you deploy afront-end server (see Chapter 2)

Branch sites:Smaller branch offices and peripheralsites that rely on a central sites servers to delivermost of their Lync services

Determine the number of users per site and how manycalls they typically make during a day

Estimate how much bandwidth you need between sites byusing the enterprises data wide area networking (WAN)

Understand your requirements for survivability, highavailability, and disaster recovery this drives both

bandwidth and server requirements

Different deployment modelsPerhaps the biggest decision you make when planning a LyncEnterprise Voice deployment is how youre going to handle



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the offload of voice calls from your network to the PSTN. Lyncgives you options for PSTN interconnection, and what you

choose affects how youre going to build out the rest of yournetwork.

Lync Enterprise Voice is a VoIP system that utilizes the SIPprotocol for session management and routing. You cant justplug it in to a traditional phone service (like a T1 voice linefrom the phone company) without translating the SIP signal-ing and call data first.

The basic distinction in deployments is how you connect yourenterprise to the rest of the world via the PSTN. You have twochoices here:

Connect to standard TDM (time division multiplexing)telephone services

Using TDM telephone services can be expensive and isntthe recommended model.

Connect, via SIP Trunking, directly to an ISP, who thenhandles any connections to TDM phone networks withinits own network infrastructure. You also need a SessionBorder Controller (SBC) to help secure and control thisconnection.

There is one other option here for remote branches. You maywish to install a device called aSurvivable Branch Appliance(SBA) orSurvivable Branch Server(SBS, the difference is in

scale the server is for larger branches) that enables directconnectivity to the PSTN in case the WAN link between thatbranch and the main office suffers an outage. SBCs, SBAs, andSBSs are covered in more detail in Chapter 4.

Branch sites typically connect to the PSTN via a Central Site traffic flows between the branch and central site over theenterprise Intranet connection and then on to the PSTN via agateway or IP-PBX or a SIP Trunk to an ITSP.

Choosing a deployment modelSo which model traditional TDM telephone service or SIPTrunking is best for an enterprise? Of course the answer



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isit depends. Companies that choose SIP Trunking do sobecause

SIP Trunking provides great consolidation of PSTN con-nectivity into a single central site.

SIP Trunking provides a simpler deployment, with lessequipment to buy, manage, and maintain.

SIP Trunking call costs are typically considerably lowerthan TDM calls.

Some ITSPs supporting SIP Trunking charge only by band-width costs, completely eliminating per-minute charges.

This may seem like a slam-dunk case for deploying with a SIPTrunking model, but a few enterprises may choose to main-tain some degree of TDM telephone service. Typically this willbe due to a large existing investment in IP gateways, in whichcase the enterprise may choose to move to SIP Trunking in aslower, incremental approach.

Industry estimates vary widely on the cost savings realized byusing SIP Trunking for connection to external networks. Aboutwhat percentage of cost do you see as actual reductions inexpense for SIP Trunks that you have implemented? Checkout Figure 3-1. This graph of cost savings from SIP Trunkingderives from a recent Sonus sponsored study.

Figure 3-1:Typical SIP Trunking savings.



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Reviewing a Lync EnterpriseVoice Case Study

Sonus recently migrated to an enterprise-wide Lync UCdeployment, including a transition from disparate voicecommunications architectures to a unified Lync EnterpriseVoice infrastructure.

First some background. The company has major headquarters,

technology centers, and branch offices located throughoutthe world. In 2012, the company acquired a firm that hadalready recently completed its own migration to Lync andLync Enterprise Voice. After the acquisition, with the increasein employees and locations as well as the added complexityto the companys voice communications infrastructure, Sonusstruggled to productively and economically provide voice ser-vices to its global employees.

In particular, the complexity of dealing with and managingmultiple communications and collaboration systems out-stripped the productivity offered by those systems. The com-pany decided quickly and to standardize on Microsoft Lyncand Lync Enterprise Voice.

Sonus set and met targets to get the entire combined enter-prise up-and-running on Lync messaging, video/voice, andcollaboration in just eight weeks and to completely move all

communications (including outside-the-enterprise commu-nications via the PSTN) to Lync Enterprise Voice within sixmore months.

In order to support the migration to Lync and Lync EnterpriseVoice, the company replaced numerous IP voice gatewayswith a single Sonus SBC with SBA capabilities in each office.Functionally, the migration to Lync and Lync Enterprise Voicebenefitted the company in several ways:

Each employee can click-to-call colleagues from IMor e-mail when the colleagues presence indicatedavailability.

Global interactive whiteboarding sessions supported byLync allow coworkers across the country and around theworld to collaborate in real time.



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Audio conferences for up to 200 people can be set up onthe fly in less than a minute.

Remote and telework employees are able to connect andcollaborate with coworkers no matter where they are.

The companys CIO noted that employee productiv-ity was measurably improved by the Lync and LyncEnterprise Deployment.

Beyond productivity increases from the migration to Lync,the company reaped direct financial benefits:

Significant savings approximately $40,000 per officeper year by replacing existing IP gateways with asingle SBC in each office

An estimated quarter million dollar decrease in Capex(capital expenditures) for telecom based on the migration

A savings of $150,000 per year on operational expenses(Opex) due the simplified management and operational

expenses for the unified Lync deployment compared toprevious disparate systems

Over $200,000 per year saved on conferencing expensesby keeping internal conferences on network within theenterprises own SIP-based WAN (or Intranet) using Lync

Notably, this savings occurred while the enterprise sawa substantial increase (over 50 percent) in conferencingminutes driven by the ease-of-use of Lync conferencing.



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Chapter 4

Getting the Most Out ofLync Enterprise Voice

In This Chapter Getting into IP-PBXs and IP Gateways

Understanding Lync Survivability

Introducing the Survivable Branch Appliance (SBA)

Knowing the role of Session Border Controllers (SBC)

In Chapter 3, we discussed the elements needed to incor-porate Enterprise Voice in a Lync Unified Communications

(UC) deployment. In this chapter, you discover the devicesthat enable that internal Lync to external PSTN calling. First,we introduce Internet Protocol (IP) Gateways and IP-PBX(Private Branch Exchange) devices that are especiallydesigned to translate between SIP VoIP and Time Division

Multiplexing (TDM) phone services. We discuss the conceptof survivability how to keep the phones on when theworst happens and the survivability-focused hardware thatgets installed in smaller branches of an enterprise using LyncEnterprise Voice. You also find out what a Session BorderController (SBC) is.

IP-PBX/GatewaysEnterprise PSTN connectivity for an Enterprise Voice requiresa connection to a TDM phone provider that utilizes a stand-alone IP Gateway or an IP-PBX with integrated IP Gatewayfunctionality.



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AnIP gatewaycan be a standalone, single-purpose device, orit may be part of a multi-purpose device that includes IP gate-

way functionality. It will be paired with an SBC for securityand media handling functionality.

You may also see IP Gateways referred to asMedia Gateways,VoIP Gateways,orPSTN Gateways.

In an enterprise environment, an IP gateway is typically con-nected between an IP-PBX and a TDM-based service providerphone service connection (known as trunk lines). The IP

gateway functionality may also be integrated directly into theIP-PBX, where the PBX connects directly to trunk lines.

IP Gateways may also be used with legacy TDM PBXs, in orderto connect them to SIP Trunking service provider connections.

Not every IP Gateway or PBX is compatible with LyncEnterprise Voice. Check out a list of certified compatible gearat go.microsoft.com/fwlink/p/?linkId=202836.

For connection to the PSTN, a device that translates betweenthe SIP-based VoIP calls used by Lync Enterprise Voice and theTDM calls supported by traditional telephone service provid-ers. The IP Gateway and some IP-PBXs can perform this job.

IP Gateways have one overarching function, which is to sup-port connectivity and conversion between VoIP and PSTNprotocols and signaling. In conjunction with the SBC, the IP

Gateway may also help to

Convert transmission and encoding techniques calledtranscoding

Support signaling protocols for both sides of the conver-sion (SIP on the Lync side of the network, TDM on thePSTN side)

Support the networking protocols on both sides of the

gateway typically this will be Ethernet within the LyncEnterprise Voice network and standard TDM networkingprotocols such as T1 or E1 on the PSTN side

Maintain toll-quality voice quality in calls by supportingfeatures like echo cancellation and low latency (delay)during calls



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Chapter 4: Getting the Most Out of Lync Enterprise Voice 25

Making Enterprise Voice MoreRobust with Survivability

For enterprises with more than one location which ispretty much all medium and large enterprises there is adesign factor that both increases the efficiency and cost sav-ings of the Enterprise Voice deployment and creates a vul-nerability in the system. In particular, branch sites typicallydepend on a central site for call control and connections to

the PSTN because the front- and back-end servers and oftenthe Mediation Server, as well, are located in the central site(usually the main office). So users in branch sites depend onprocessing that occurs in the central site(s) for their UCconnectivity.

The centralized control of the Enterprise Voice networkleaves two points of vulnerability:

If theres a disruption in service to the enterprise WANconnection between the branch and central site, thebranch site loses all communications connectivity bothwithin and outside of the enterprise.

If theres a server outage in the central site, the branchoffice has network connectivity, but users there areunable to communicate.

In these two instances, you can see that its imperative toarchitect the Enterprise Voice network in such a way thatbranch sites arent left out in the cold.

The main safeguard against these types of outages is theinstallation of survivable equipment in branch sites. Thisequipment includes Lync Enterprise Voice network gear thatcan pick up some of the processing and connectivity slackwhen the worst happens. Its essential to spend time whilearchitecting the network to make the network more resilientand survivable in the following locations:

Central sites:This process involves building sufficientredundancy into the network. For example, an EnterpriseVoice deployment can be made more redundant andresilient by installing backup server pools in other



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locations and then defining failover routes within thenetwork, so services can be seamlessly delivered after

failures. Branch sites:The installation of aSurvivable Branch

Appliance(SBA) provides the backup processing andPSTN connectivity to keep a branch online during afailure situation. More on SBAs in the later sectionUnderstanding SBAs.

All sites:The installation of an SBC provides additionalsecurity and intelligent routing of calls whatever the net-

work status is.

Understanding SBAsIts the role of the SBA (and its larger sister, theSBSSurvivable Branch Server) to provide resiliency and survivabil-ity (hey, its right in the name!) for Lync Enterprise Voice branchsites. When a branchs communications are provided through aLync server in the central site, the loss of WAN connectivity canleave branch offices with neither internal (for example, station-to-station) nor external communications capabilities.

SBAs at each branch office make it possible for those officesto continue to provide basic voice telephony services toemployees when network connectivity to the main office islost. Specifically, an SBA makes this possible by functioningas a local PSTN gateway and providing basic voice telephonyservices to employees in the branch office. When the connec-tivity to the main office is restored, the branch office revertsback to the original configuration and telephony calls areonce again processed by the main office telephony system.Pretty neat trick, huh?

Resiliency and survivability dont mean that every singleLyncservice works without a hitch during a central site or WANoutage. Instead, it means that the most essential services stayon until the network is fully restored. By essential services,we mean things such as the following:

Inbound and outbound PSTN calls

Internal enterprise calling both within the site andbetween sites



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Basic IM

Dial-in (PSTN) conferencing

Voice mail

Other services like E911, web or videoconferencing, andother advanced Lync features may not be available untilthe network is fully restored. But enterprise employees cankeep communicating and working right through the outage,which, for many businesses, is downright essential.

The SBA is designed for smaller (but not necessarily small!)branches. Microsofts recommendations for when to deployan SBA/S are as follows:

Branch sites between 25 and 1,000 users should getan SBA.

Branch sites between 1,000 and 2,000 users shoulddeploy either two SBAs or an SBS.

Sites that support up to 5,000 users or require local pres-ence and conferencing features should be bumped up tothe central site level and deploy Lync server.

Regardless of which approach is taken, a key to resilientbranch deployments is the addition of connectivity to exter-nal phone services. To provide this, a branch site can use oneof two options:

Connect the SBA or SBS to an IP gateway

Connect the SBA or SBS directly to a SIP Trunk connec-tion to an ITSP

This connectivity allows users within the branch site environ-ment to bypass the usual SIP connection to its serving centralsite and to instead route calls through a different communica-tions channel, while the SBA or SBS takes over the call han-dling duties usually performed in the central site.

The SBC may, in many cases, include Lync SBA functionality(and certification). In this case, a single device can handlethree key functions:



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UC network security and intelligent routing

SBA functionality in case of a network or central siteserver outage

Connectivity via SIP Trunking to an ITSP (if the branchuses SIP Trunking instead of an IP gateway)

Figure 4-1 shows a typical branch office SBA with an SBC(acronyms galore!).

Figure 4-1: A branch office SBA with an SBC.

Introducing the SBCThe SBC plays a big role in a Lync Enterprise Voice deploy-ment and sits on the edge of the network (between the enter-prises and the phone companys networks) and provides allsorts of security and mediation services to keep things run-ning smoothly. It communicates between two network enddevices, such as a Lync SIP VoIP call between two phones.These communications are calledSIP sessions. The SBC doesthis session controlling at the point where traffic is handed offfrom one network to another (called the border) like where

traffic leaves the enterprise and goes onto a service provid-ers SIP trunks. Because of where the SBC fits in the network,it can be usefully implemented by both businesses themselvesand also by the service providers who serve them.



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Lync Enterprise Voice network operators both enterprisesand service providers face threats to the security of their

network and business and also face more everyday issuessuch as how to make VoIP work seamlessly and efficientlywhile also realizing the cost and bandwidth savings that VoIPpromises. Thats what makes SBCs really worth deploying inan Enterprise Voice network.

Some of the main roles of an SBC include the following:

Protecting the network from attacks and fraud:

Denial of Service (DoS) attacks:Bad guys attemptto overwhelm the network with fake connections.

Spoofing attacks:Nefarious users attempt to gainaccess to the network deceptively.

Toll fraud: Hackers attempt to access the networkin order to route calls over it at the network ownersexpense.

Enabling SIP trunking, allowing the network owner tosave money and operate more efficiently by connectingdirectly to an ITSP via SIP trunks

Enabling better communications in varied network envi-ronments

For example, a deployment where existing IP-PBXs andother legacy telephony equipment is integrated with theEnterprise Voice deployment. The SBC is designed tosmoothly translate between varying network protocols,codecs (encoders/decoders for digitizing media), band-widths, and more.

In Chapter 5, you take a closer look at the role of SBCs in LyncEnterprise Voice networks.



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Chapter 5

Leveraging SBC forEnterprise Voice

In This ChapterMaking the SIP trunking connection

Making IP PBXs work well

Ensuring service quality

Supporting E911

Helping different PBX vendors play together nicely

Centralizing control and troubleshooting

The Session Border Controller (SBC) is a device that pro-vides a host of security, service enablement, and control

functions for any VoIP or Unified Communications (UC)network. Enterprises use SBCs for all sorts of UC network

deployments, as do service providers.

The SBC which Microsoft recommends be included in aLync Enterprise Voice Deployment to ensure interoperabilityand functionality sits at the border between the internalLync Enterprise Voice network and the SIP Trunk serviceprovided by the Internet service provider (ISP) or a legacyInternet protocol (IP) telephony infrastructure.

In a Lync Enterprise Voice UC deployment, the SBC plays sev-eral key roles discussed in this chapter. First, we discuss howSBCs enable and improve SIP Trunking for connections to ISPs.Then we discuss the role of the SBC in integrating IP-PBXs with aLync deployment. You also discover how SBCs improve servicequality and make E911 services work. Finally, you delve intohow SBCs help with multivendor compatibility and central con-trol and troubleshooting of the Enterprise Voice deployment.



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As we mentioned in Chapter 4, in Lync branch sites, the SBCmay also serve the role of survivable branch appliance (SBA).

Connecting to SIPTrunking Services

While some enterprises may use TDM voice services withtheir Enterprise Voice deployment, a growing number are

taking the VoIP revolution to its logical conclusion andpartnering with SIP Trunking ISP partners. In a SIP Trunkingdeployment all calls entering and leaving the enterprise arecarried as SIP packets across a data connection there areno phone lines like there are in a TDM deployment (wherean enterprise may lease access to a T1 or E1 line with a fixednumber of lines associated with that transmission facility).

Instead, SIP Trunking uses a standard service provider data

connection which may be shared with other data/Internetservices or dedicated to the purpose of SIP Trunking. Theenterprise isnt paying for lines; its paying for bandwidth.Any VoIP to PSTN translation thats required in a SIP Trunkingdeployment (for connection to regular phones outside ofthe enterprise network) is handled by the ISP. Everything thatenters and leaves the enterprise network is pure IP.

PSTN connections may still exist for disaster recovery pur-

poses, as discussed in Chapter 4.

The SBC is an essential part of a SIP Trunking deployment.The SBC performs a few key functions:

A gatekeeper role: The SBC looks at each SIP packetcrossing between the Lync network and the external ISPnetwork, determining which should be allowed throughand how they should be routed.

An interworking role: The SBC allows SIP systems totalk to each other even if they speak different dialectsof SIP. Among the translations that an SBC can perform are

SIP normalization:SIP is a standard, but there aresubtle variants in the way SIP is implemented theSBC can understand all of them and modify the SIP



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Chapter 5: Leveraging SBC for Enterprise Voice 33

packets to ensure both ends of the call can get thefull picture and understand each other.

Transrating: SBCs can modify the bit rate of calls,videoconferencing, and other SIP sessions cross-ing the network to accommodate different devicesand different network segment capabilities. Forexample, a video call may be transrated to a lowerbit rate to accommodate an endpoint on a mobilenetwork.

Transcoding: SBCs can translate in real time

the codecs (encoding and decoding protocols)used for digitizing and transmitting calls. This canbe essential when the endpoint devices involved ina call support different codecs.

Network security:The SBC controls the admission ofcalls in and out of the enterprise and protects the net-work against denial of service attacks, toll fraud, andother attacks against the Lync Enterprise Voice network.Additionally, the SBC can hide the topology of the Lyncnetwork within the enterprise, so external parties arentable to detect the devices within.

Integrating with ExistingIP-PBX Platforms

Many enterprises migrating to Lync Enterprise Voice have anexisting base of IP-PBXs already in place, performing the samesorts of call functionality provided by Enterprise Voice. Inthese cases, most enterprises dont choose to perform a ripand replace wholesale replacement of the existing infrastruc-ture in favor of a Lync Enterprise Voice infrastructure.

Instead, most gradually implement Enterprise Voice whileretaining some or all of the IP-PBX infrastructure. In some

cases, this will be to leverage the TDM telephony interfacesoffered by the IP-PBX, while in other cases, the IP-PBX willstay in service to provide specific services or to serve somesegments of the network while others are transitioned toEnterprise Voice.



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The SBC plays a vital intermediation role and can provide SIPnormalization, transcoding, and transrating to allow a smooth

integration between Enterprise Voice and the IP-PBX.

Most larger enterprises have a disparate IP-PBX base morethan one vendor serving the company with different IP-PBXsin different locations. In these cases, an SBC is even more vitalto a smooth integration because its likely that each of thesedifferent IP-PBXs will have its own SIP variations and trans-coding requirements.

In addition to the SIP normalization and transcoding/ratingfunctions, SBCs also serve to provide a centralized call rout-ing intelligence located logically above both the IP-PBXsand the Lync Enterprise Voice servers. So the SBC can bethe brains of the deployment, helping to ensure that callsare routed correctly, with the most efficient use of networkresources and the lowest costs.

Ensuring QoSQuality of Service (QoS) is important in all communications voice, video, or data but its of particular importance forvoice communications, where any degradation of sound qual-ity, introduction of delay, or jitter (essentially, a change indelay that can cause audible artifacts in a call) can make thecall annoying or even unintelligible.

In Lync Enterprise Voice QoS, the SBC monitors, controls, andactively improves calls moving across the network. The SBCdoes this by:

Call Admission Control:The SBC decides which calls canbe allowed on the Enterprise Voice network based oncustomizable policies set up by the enterprise to keepthe network running smoothly during busy call periods.

Transcoding/rating:The SBC can use more efficientcodecs when the networks bandwidth is near capacity.

VoIP prioritization:The SBC can place voice calls higherin the pecking order (over things like video or webconfer-encing) when the networks capacity is being filled up.



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Media Bypass:Lync supports a process known asMedia Bypasswhere the Lync Mediation Server can be

bypassed. Media Bypass can greatly reduce the load onthe Mediation Server, ensuring proper capacity for callsthat cant be bypassed.

Monitoring the networks health:The SBC monitorsbandwidth usage, latency, jitter, and other metrics andthen feeds that data back into call admission control andother functions.

Supporting E911Lync supports E911. What is E911 you ask?Enhanced 911 isemergency services calling that provides location informationto responders by adding location information to calls soemergency responders can automatically pinpoint the loca-tion of those calling for services.

Just because Lync supports E911 doesnt mean that it willjust work right out of the box though. The SBC can help in anumber of scenarios:

For Enterprise Voice deployments connecting via TDMand an IP Gateway, the SBC can support the connection tothe appropriate local Emergency Response Location (ERL)and pass along standards-compliant location data something that Lync cant do on its own (over a TDM

connection).

In a SIP Trunking environment, the SBC supports E911 intwo ways:

In some cases, the ISP may not carry the locationcomponents of the SIP signal. In these cases, a TDMline may be connected to the SBC, and E911 willoperate as discussed in the previous bullet point.

In other cases, the ISP will carry the E911 informa-tion but requires a direct SIP trunk connection tothe Lync Mediation Server from the 911 service pro-vider something not all enterprises wish to dofor security reasons. The SBC can serve as a proxybetween the 911 network and the Lync network,passing all necessary location data, while maintain-ing network separation and security.



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Dealing with Interoperabilitybetween Vendors

SBCs are really good at playing the role of intermediarybetween the Lync servers and a SIP trunking provider. TheSBCs ability to normalize SIP and to transcode and transratemedia makes it the perfect go-between in any sort of VoIP net-work deployment.

SIP equipment vendors whether theyre making IP gate-ways, SIP VoIP client devices, or whatever, really tend tohave their own slightly distinct variations of the SIP protocolstandard. Its not like one is speaking English and the other isspeaking Mandarin; its like one is speaking Australian Englishwhile the other grew up in Boston. The words and constructsare the same, but occasionally they cant quite understandeach other.

Many perhaps even most Lync Enterprise Voice imple-mentations involve equipment from more than a singlevendor. This is especially true in larger enterprises or enter-prises that are transitioning their exiting VoIP UC deploy-ments to Lync.

Chances are good that there are some subtle but impactfulincompatibilities and differences in the way these differentdevices use SIP. The impact is often missed or dropped calls

or just a plain the networks not working type of scenario.Putting the SBC in between these disparate network elementsand letting it do what it does best (enabling network inter-working) is the solution.

Centralizing Control and

TroubleshootingBecause SBCs sit in a unique place in the Enterprise Voicenetwork at the edges of the network where voice and otherUC traffic transitions between locations and between networkborders they can also play a unique role: that of centralcontrol point in the network.



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The SBC can control the network through its role as calladmission control point and through its intelligent call routing

capabilities. These functions are governed by robust policycapabilities that let the enterprise or a service provider pro-viding Lync Enterprise Voice determine and enforce centrallyestablished rules about call permissions and behaviors.

In other words, the SBC can provide an overarching, policy-based control layer on top of the UC network, determining(on a call-by-call, person-by-person, or group-by-group basis)how or even if calls should be routed across the network

and what network resources they should be assigned.

As part of this process, the SBC tracks the performance andutilization of each UC network element. That means when itcomes time to track down a problem or to optimize policiesand network topologies, the SBC can help pinpoint the areasthat need attention.



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Chapter 6

Ten Reasons to ChooseSonus when Deploying

Lync for Enterprise VoiceIn This Chapter Supporting a wide range of compatibility and interoperability

Providing resiliency and protection from attacks

Getting centralized management

The Session Border Controller (SBC) is a key elementin securing, controlling, maximizing QoS, and enabling

services (like SIP Trunking and E911) in a Microsoft LyncEnterprise Voice deployment. Sonus Networks is a vendor forSBCs and has a lineup that just may be a great choice for yourEnterprise Voice deployment. In this chapter, we give you ten

reasons to choose Sonus for Enterprise Voice.

Microsoft Compatibilityand Qualification

Sonus is a qualified Microsoft Lync hardware partner and hasseveral models of SBCs certified for use in a Lync Enterprise

Voice environment. So you can rest assured that your net-work will be compatible.

Proven ExperienceMany large banks, retailers, and airlines trust Sonus already.Its one of the faster growing brand of SBCs.



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Multivendor InteroperabilitySonus SBCs are deployed throughout the world in a variety ofenvironments, supporting Lync Enterprise Voice and a widerange of IP-PBXs and legacy TDM-PBX systems in differentconfigurations.

Sonus has a broad range of compatibility and interoperabilityin the industry. So no matter what your legacy situation andno matter how youre transitioning to Lync Enterprise Voice,

Sonus has you covered.

Maximized Resiliency andProtection Against DoS Attacks

Keeping the lights on is important in any network environ-ment. In an Enterprise Voice environment its critical. Sonus

SBCs are designed to provide high availability, enabling callsto be completed even under peak conditions.

For larger deployments, Sonus SBCs can be deployed in pairs(in whats calledActive-Active mode), to provide load balanc-ing and even high availability. Sonus SBCs can additionallybalance the call load across multiple Lync Mediation serversto keep the network up no matter what.

Resiliency can really come into play when a network is com-promised by a Denial of Service (DoS) attack. Such an attackcan cripple an enterprises voice services by simply overload-ing servers with malicious incoming IP traffic.

Sonus SBCs offer sophisticated real-time firewalling and theuse of techniques such as Virtual LAN (VLAN) tagging, whichdrops the malicious packets and allows legitimate traffic tocontinue on to the network unimpeded. So the enterprise

stays online and productive!

Encrypted CommunicationsKeeping sensitive enterprise conversations away from eaves-droppers is the role of encryption in an Enterprise Voice



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Chapter 6: Ten Reasons to Choose Sonus for Enterprise Voice 41

deployment. The SIP standard itself uses plain text signaling,so nefarious parties on the Web may be able to intercept a

SIP-based call.

With a Sonus SBC and its support for AES encryption (128 bit),potential eavesdroppers arent able to make head or tails ofa conversation they might be able to otherwise listen in on.And Sonus SBC architecture which separates encryption-processing tasks to its own processor architecture within theSBC allows real-time encryption processing to take placewithout causing slow-downs in other SBC functions such as

call routing or media processing.

Rapid RecoveryOutages happen. Hopefully (and in most cases) not very often,but in real life they do happen. Sonus SBCs are built to makethe disruption of an outage a minor rather than a major event.

For example, Sonus SBCs typically include redundant powersupplies, so a failure of a power supply can be handled with-out a hitch. And if something external to the SBC causes theoutage (like an outage of the enterprise WAN connection),Sonus SBCs are ready.

Sonus SBCs continually monitor the health of the network,pinging other nodes in the network to ensure that links areup and running. If a failure occurs, the Sonus SBC automatically

attempts to find alternate routes to complete calls without theend-user ever knowing that theres a problem. In branch sites,the Sonus SBC can automatically reroute calls to the PSTN (oreven to a mobile network) when the IP network goes down,giving the user the service she needs without disruption.

Survivability for Branch SitesIn Chapter 4, we talk about Survivable Branch Appliances(SBAs). Sonus SBCs include full support for Lync SBA.In fact, Sonus takes this one step further and supports fullLync Enhanced SBA with 3G/4G failover capability. So anenterprises branch sites get high-quality voice services,ready-to-go survivability and require one less device in the



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network that makes the network simpler and cheaper toprovision and manage.

Centralized Policy ManagementSonus SBCs can be centrally managed. Whether an enterprise(or service provider) needs two SBCs or 20, a single set of poli-cies and configurations can be established one time and sentto all locations with one action, which means lower expensesfor IT and better/faster results for users. This streamlining alsoeliminates the need to hire or send expensive IT technologiststo each location in the network to maintain and update policies.

Exceptional TranscodingPerformance

Often voice calls arent in the same codec, such as when inlanguages a translator or in UC a transcoder is needed to con-vert between the two. The Sonus SBC platform has a separateprocessing architecture of media transcoding and transrat-ing, so the overall performance of the SBC doesnt take a hitwhen a lot of processor-intensive transcoding is going on.Whatever the transcoding load, the encryption/security andthe routing modules are unaffected.

Additionally, this functionally separated architecture makes iteasier and less expensive to add more processing power fora specific function without requiring the enterprise or serviceprovider to upgrade other parts of the SBC that are adequatelyprovisioned.

Wide-Ranging Media SupportSonus SBCs provide a wide range of support for differentmedia types because it doesnt rely on off-the-shelf solutions(with its generic off-the-shelf software) for media processing.Instead, Sonus creates its own firmware, which allows Sonusto responsively add additional media types as needed withoutwaiting for a vendor to come along with a solution.



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Documents

Lync for Dummies