Lync® Enterprise Voice For Dummies®, Sonus Special Edition

By Mohan Palat and Kevin Isacks

Lync® Enterprise Voice

Sonus Special Edition

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Lync® Enterprise Voice For Dummies®, Sonus Special EditionPublished by John Wiley & Sons, Inc. 111 River Street Hoboken, NJ 07030-5774 www.wiley.com

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

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

Chapter 1: Taking a Peek at Unified Communications . . . . . . . . . . . . . . . . . . . . . . . . .3

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

Chapter 2: Getting Acquainted with Microsoft Lync . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

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

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

Understanding Your Options for 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 . . . . . . .15What is Lync Enterprise Voice? ............................................. 16

Looking into Lync Enterprise voice features ............. 16Making Lync Enterprise Voice work............................ 17Planning for deployment .............................................. 18Different deployment models ....................................... 18Choosing a deployment model .................................... 19

Reviewing a Lync Enterprise Voice Case Study ................... 21


Lync Enterprise Voice For Dummies, Sonus Special Edition ivChapter 4: Getting the Most Out

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

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

Chapter 5: Leveraging SBC for Enterprise Voice . . . . . .31Connecting to SIP Trunking Services .................................... 32Integrating 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 when Deploying 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............................................. 42Exceptional Transcoding Performance ................................. 42Wide-Ranging Media Support ................................................. 42


ForewordFor many organizations, the search for the next technology to deliver 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, and other services. Organizations can streamline business pro-cesses and increase productivity by assuring that the right communications happen at the right time, with the right people, and the right tools. Most Lync deployments start as an internal trial and then deploy, but extending Lync beyond the boundaries of the organization can yield equal or even greater benefits than internal use alone. By using Lync federation, capabilities can be extended to partners and customers, reducing costs and increasing business success. Using Lync conferencing can reduce conferencing costs and, when com-bined with Lync telephony services, can deliver a truly unified user experience. You may also experience a reduced cost with traditional legacy telephony equipment.

However, when Lync is extended beyond the organization boundaries issues of interoperation, security, control, and management emerge. Organizations contemplating Lync deployment should begin planning for external Lync capabili-ties. Even if the initial deployment is internal, often users and departments will drive rapidly for external Lync capabilities, so make sure you plan ahead.

One key element of a successful external Lync deployment is a Session Border Controller (SBC) that can manage and assure the 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 issues and complexity of a Lync Enterprise Voice deployment. It gives the reader the initial tools to begin to make the right decision to assure personal, solution, and organization success with Lync Voice.

Phil Edholm PKE Consulting LLC & UCStrategies.com

[email protected] www.pkeconsulting.com


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Introduction

E 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 so they work together seamlessly and in a (well, we’ve got to say it) unified way.

With UC, an enterprise user can use a single software applica-tion (app) on his desktop, laptop, tablet, or smartphone to communicate and collaborate with colleagues, customers, and partners through instant messaging, voice calls, conference calls, videoconferences, screen and application sharing, and more. If you’ve not used it before, well, it’s awesome.

About This BookOne of the leading software platforms for UC is Microsoft’s Lync. In this book, we talk about Lync and give you an idea just what it’s all about and what kinds of UC services Lync supports. Most importantly, we introduce you to Lync Enterprise Voice — an additional element of Microsoft Lync that enables the Lync platform to completely replace a tradi-tional enterprise Private Branch Exchange (PBX). (In case you didn’t know, a PBX is the business phone system that most enterprises use to enable things like call transfers, call hold-ing, conference calling, and more).

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


Lync Enterprise Voice For Dummies, Sonus Special Edition 2Is your enterprise thinking about implementing UC? Or have you already got a Lync deployment and you’re 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, then Lync 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 icons on the left margins of the page. You’ll find four such icons:

The Tip icon points out a bit of information that aids in your understanding 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 out parts of the text to lock away in your memory for future use.

Watch out! This information tells you to steer clear of things that may cost you big bucks, suck your time, or be bad practices.

We try to keep the technical jargon and discussion to a mini-mum. You won’t need to know these factoids to get the most out of the book, but you may find them interesting.


Chapter 1

Taking a Peek at Unified Communications

In This Chapter▶ Getting a handle on UC▶ Understanding the world of UC applications▶ Learning who provides UC

F or many years, companies, large and small, have relied on Private Branch Exchange (PBX) systems for their

voice telephony needs. PBXs provide business phone fea-tures, such as shorter numbers for internal dialing, call transfers, and bridging conference calls. The rise of Internet technologies like Voice over Internet Protocol (VoIP) has driven 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 its Enterprise Voice components, offers a full replacement for a traditional PBX service. In order to create a robust and high-quality UC voice service for an enterprise with Lync, you also need 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.


Lync Enterprise Voice For Dummies, Sonus Special Edition 4

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

Understanding UCUC is the next evolution in enterprise communications and collaboration technologies, bringing all varied connections under 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 (Internet protocol) network through the following mechanisms:

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

✓ Video: Videoconferences, on-demand video learning, and so on

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

The unified part of UC refers to the fact that the UC hardware and software take all these communication applications and put them under the purview of a common control system instead of using different hardware and software solutions for each 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 even as a speech-to-text translated message.

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


Chapter 1: Taking a Peek at Unified Communications 5

Presence simply means the ability and willingness of an indi-vidual to receive certain types of communications. If you’ve ever used Skype or an instant messaging program, your status (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 how and when to deliver your communications to you. For example, if you’re out of the office and at a meeting, a UC system may route calls to your mobile device and also not even try to ring the phone.

This combination of multiple platform, client, and communi-cation methods with presence and location data is a powerful tool — one that can greatly streamline and improve the ways that enterprise employees communicate, coordinate, and col-laborate with each other, whether they’re in a single location or spread across the globe. Say goodbye to playing phone tag and 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 using software applications (apps) on PCs or Macs or on mobile and tablet devices. With a UC system, users no longer need a PBX system to make voice or even video calls to others. Users also save a lot of money in voice calls 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 chat sessions, the ability for an IM session to pass between devices, 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-person or, depending on the system, between groups of people.

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



Don’t limit your UC apps to the desktop. UC platforms can support mobile devices as fully integrated clients. To make this work, you need a working data connection on the mobile device 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 provide it to your customers if you’re a service provider) includes a few key elements:

✓ Connectivity to an IP network, usually including SIP Trunking services

✓ A server (or servers) to run the UC applications and pro-vide back-end functionality, such as directory or contact servers, 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 servers and software within your own datacenter or server room and 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, a third-party service provider manages for all the servers, software, and operations — the enterprise just pays to use.

✓ Hybrid deployments: Some functionality is installed on the enterprise premise while other functionality is hosted in the cloud by a service provider.

Whether an enterprise deploys UC on its own or through a hosted service, it still requires connectivity through a SIP Trunking service provider or Internet Telephony Service Provider (ITSP). The ITSP provides bandwidth and connectiv-ity and (in most cases) connectivity to the Public Switched Telephone Network (PSTN).


Chapter 2

Getting Acquainted with 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

E nterprises of all sizes and kinds are adopting Unified Communications (UC). (Check out Chapter 1 if you’re

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

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

What Is Lync All About Anyway?

Microsoft has been investing in and developing applications for communications and collaboration for a long time. Lync is the latest and greatest — and far more advanced — evolution in the long line of products.



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

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

✓ A UC server running the UC software platform in the datacenter (which could be inside the enterprise or hosted by a third party)

✓ UC software running on the end-user’s PC, phone, or tablet

Lync provides both the server software (hosted by your own datacenter or by Microsoft itself) and the app software for various platforms to enable a robust voice, video, and data UC solution appropriate for any enterprise. Because it’s a unified platform (it is UC, after all), Lync supports all the UC applications using a single-server platform and a single appli-cation, meaning there’s less to learn, less to deploy, and less to manage.

Understanding Lync Servers and Apps

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

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

✓ Instant Messaging (IM) and presence: Exists both within the 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 videoconference and allows users to share screens and applications, enjoy collaboration, manage voice and chat (IM) meetings, and


Chapter 2: Getting Acquainted with Microsoft Lync 9conduct virtual meetings anytime, anywhere, and on any device (including mobile).

✓ Enterprise voice: VoIP support for person-to-person and multipoint audio calls, including standard Private Branch Exchange (PBX), which is an enterprise telephone system functionality such as voice mail, call holding, forwarding, and so on.

✓ Connection to the PSTN (Private Switched Telephone Network) or SIP (Session Initiation Protocol) Trunking: Supports calling outside of the enterprise network via connection to either a traditional phone company or to an Internet Service Provider (ISP) that offers voice ser-vices via a SIP Trunking connection.

✓ Support for remote and mobile users: Fully supports remote and branch office users, telecommuters, and mobile workers.

Many other functions aren’t mentioned in this list — Lync literally supports dozens of apps and services (you can find an exhaustive, too-long-to-print list on Microsoft’s website).

Lync Server utilizes the SIP protocol as the underlying pro-tocol for routing and controlling communications within the enterprise network and beyond. SIP is a standardized proto-col used for supporting voice, video, and conferencing over common Internet Protocol (IP) networks. Using SIP ensures that 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 an enterprise. We cover these in more detail in the section “Understanding Your Options for Lync Server Deployment” later in the chapter.

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


Lync Enterprise Voice For Dummies, Sonus Special Edition 10 ✓ Microsoft Lync software: This is the primary way that

most of you will use Lync. The Microsoft Lync client soft-ware supports all Lync functionality through one stop shopping — users can rely on a single app on their PCs for IM, to set their presence preferences for video and voice calls, and for collaborative conferencing.

For clarity’s sake, we’ll always use the word “client” when we’re discussing the client software.

✓ Web client: Users aren’t required to have the client soft-ware on their computer to use Lync. Lync supports full-featured client access via a Web browser interface. All that’s needed is an HTML 5 compliant browser (meaning the latest versions of Internet Explorer, Safari, Chrome, or Mozilla) on a PC or Macintosh laptop or desktop computer.

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

✓ Lync-enabled phones: Not everyone wants to talk through a PC or tablet (or even a mobile device) all the time. With that in mind, Microsoft has certified a number of phones and related devices that serve in a Lync UC network.

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 Options for 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 host the Lync Server software itself in its own datacenter. There


Chapter 2: Getting Acquainted with Microsoft Lync 11are 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) handles user authentication, presence information, contact and address book functionality, and the delivery of applica-tions. The back-end server hosts the databases to make the front-end servers work.

There is also a Lync Standard Edition Server for smaller enterprise deployments (and for pilot deployments within larger organizations). This combines the front- and back-end servers within a single device, but it loses the redundancy and high availability of a distributed server solution, so it isn’t recommended for mission-critical larger deployments.

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

✓ Mediation server: For deployments of Lync that replace a traditional PBX service with Lync Enterprise Voice, the mediation server handles all the signaling, translation, and other media routing and handling roles. This server can be on the same hardware as the front-end server or on its own server computer.

✓ Other servers: Optionally, additional server types may be required, based on the range of services, scale, and complexity 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-based Lync Online services.


Lync Enterprise Voice For Dummies, Sonus Special Edition 12Lync Online is simply Lync delivered as a hosted service over the enterprise’s Internet connection. That means that someone else (Microsoft or another third party) owns and runs the Lync servers in its own datacenter and the enterprise accesses them via a data connection.

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

Hybrid Lync servicesYou can also deploy Lync in an enterprise via the hybrid option, 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 other functionality within on-premise servers. Specifically, a hybrid deployment may be used to

✓ Deploy Lync Enterprise Voice on-premises while utilizing Lync Online for other services (this is called Hybrid 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 Lync deployment

Choosing between the three optionsWhich of the options should an enterprise choose? Well, the primary decision point is what priority Enterprise Voice or PBX-like services hold to the enterprise — if they’re part of the goals of a Lync deployment, then the on-premise or hybrid approach is required. If an enterprise is mainly concerned with IM and conferencing functionality, Lync Online will do just fine.


Chapter 2: Getting Acquainted with Microsoft Lync 13

Applications Enabled by LyncThe services enabled by a Lync deployment include

✓ Telephony: With Lync Enterprise Voice, Lync can be a complete replacement for an enterprise’s existing PBX system. Users can call within the enterprise or (through a SIP Trunk or PSTN interface) anywhere in the world. Lync supports all the PBX functionality that enterprises expect, including conferencing, call forwarding and trans-fer, voice mail, and more. With SIP Trunking present, Lync Enterprise Voice can save an enterprise significant money compared to traditional PBX voice.

✓ IM and presence: Using their Lync clients on PC or mobile devices, users can set their presence and engage in real-time and persistent IM chat sessions with one or many users at a time. If their Lync deployment is config-ured, they can chat with Lync users in other enterprises or 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 conduct virtual meetings anytime and anywhere and on any device (including mobile).

✓ Lync meetings: Beyond video, Lync users can quickly (with one click in most cases) conduct collaborative meetings, including screen sharing, PowerPoint sharing, and other application sharing. Users outside of the enter-prise (clients and partners) can be included by using a simple URL and the Lync Web client.

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

✓ Support for Enterprise Voice (discussed in Chapter 3) in the hybrid deployment model

✓ Enhanced E911 support

✓ New and improved client appli-cations for Windows 8, Windows Phone, iOS, Android, and web browsers

(continued)



Understanding Why Enterprises Choose Lync

Millions of users are currently using Lync within their enterprises — 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 Lync deployments — Lync deployment consultancies have recently stated that over 50 percent of their new business includes Enterprise Voice. With the support for hybrid enterprise voice in Lync 2013, this number is bound to go up.

What’s driving this adoption? Several things:

✓ Lync offers integration with existing, incumbent Microsoft services, such as Outlook, and uses familiar server platforms (Microsoft Server and SQL).

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

✓ Lync’s 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 for third-party network hardware and third-party IM and conferencing applications such as Skype.

✓ Improved call management and routing features

✓ 1080p (high definition) videocon-ferencing support including calls of up to five people

✓ Updated web application sup-port, providing better access to Lync apps via the Web

✓ Greater scalability

✓ Improved management tools

✓ The ability to integrate Skype users into the contact list, see their presence information, and communicate with them

✓ Support for Microsoft Office OneNote, so a user can share a OneNote document during a Lync meeting

(continued)


Chapter 3

Digging into Lync Enterprise Voice

In This Chapter▶ Getting to know Lync Enterprise Voice▶ Seeing Lync Enterprise Voice in action

E nterprise 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 of enterprise voice for businesses by using the Microsoft Lync UC platform. With Lync, enterprises can segue from a legacy PBX solution(s) at their own pace.

The most basic implementations of Microsoft Lync Unified Communications (UC) provide an enterprise’s users with IM, presence and the ability to conduct meetings via voice, video, and collaboration software. The most basic Lync deployments, however, don’t offer all the voice communications stuff that’s handled by business PBX systems. So what’s the end result? Communications are still siloed in two distinct systems: one for users who use Lync and another for those who use the PBX (most often through their desk phones). But, with the addition of Lync Enterprise Voice — particularly the latest version of Lync, Lync 2013 — that no longer needs to be the case. Lync Enterprise Voice provides an overarching architec-ture for all of an enterprise’s communications, making them truly unified.



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 voice calls to other users within an enterprise, to other Lync users or partners, or even beyond that with web clients and Skype integration. But voice isn’t Lync Enterprise Voice. It’s merely a subset.

Think of the difference in terms of comparing a VoIP-enabled IM client running on your home PC with a phone service offered by your telco or cable company. Both let you talk to someone, but only the latter is set up to provide 911 calls (with location data) and to allow more sophisticated calling features like call forwarding, hold, transfer, and so on.

What Lync Enterprise Voice does, in a nutshell, is bring the full-fledged enterprise PBX experience under the umbrella of Lync UC. An enterprise can use Lync Enterprise Voice to supplement or even replace an Internet Protocol PBX (IP-PBX) system.

Looking into Lync Enterprise voice featuresEssentially offering everything that an enterprise may use an IP-PBX or traditional PBX to provide, Lync Enterprise Voice enables a wide range of enterprise telephony features:

✓ Connectivity to the PSTN: Lync users can call any number, anywhere (within the policy limits of the enterprise of course — no calls to Antarctica!) through connectivity to the PSTN via a gateway or SIP Trunking connection (more on these in Chapter 4).

✓ Voice calls from anywhere: Use Lync to place and receive calls from any device, in any location, through the Lync client.

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


Chapter 3: Digging into Lync Enterprise Voice 17 ✓ Call handling: You can forward calls or send them to

voice mail or to your mobile phone — all without drop-ping the call.

✓ Simultaneous ring: Incoming calls can ring on any or all your devices, so calls are never missed (except on purpose, of course!).

✓ Team calling and delegation: Configure calls to ring on the phones or devices of all members of a team or to delegate calls to an assistant.

✓ Common area phones/hot-desking: Calls ring through to phones that aren’t associated with an individual user, so you can get your calls in the conference room or at the desk you choose today.

✓ Caller ID manipulation: You use a different outbound caller ID (for example, showing the main number for an enterprise location rather than an individual’s).

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

Making Lync Enterprise Voice workSome additional hardware, server, and software requirements exist to enable Lync Enterprise Voice. At a high level, you’re going to need the following:

✓ A Lync mediation server (discussed in Chapter 2 — not a requirement for basic Lync deployments but required for Lync Enterprise Voice)

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

✓ Additional servers based on the applications you’re deploying, the number of users, and the desired redun-dancy and survivability of the network



Planning for deploymentIn order to successfully deploy Lync Enterprise Voice, your technical team needs to spend time actually planning the deployment in terms of the policies and configurations that govern your deployment and the underlying network facilities that your Lync Enterprise Voice deployment requires.

Download the Microsoft Lync Planning Tool application from Microsoft before you start designing and planning a Lync Enterprise Voice deployment. This software walks you through your actual deployment and gives you a detailed list of server and software requirements as well as a proposed network diagram to support the deployment. The Lync Server software 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 to deploy. Lync Enterprise Voice deployment contains two types of sites:

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

•Branch sites: Smaller branch offices and peripheral sites that rely on a central site’s servers to deliver most of their Lync services

✓ Determine the number of users per site and how many calls they typically make during a day

✓ Estimate how much bandwidth you need between sites by using the enterprise’s data wide area networking (WAN)

✓ Understand your requirements for survivability, high availability, and disaster recovery — this drives both bandwidth and server requirements

Different deployment modelsPerhaps the biggest decision you make when planning a Lync Enterprise Voice deployment is how you’re going to handle


Chapter 3: Digging into Lync Enterprise Voice 19the offload of voice calls from your network to the PSTN. Lync gives you options for PSTN interconnection, and what you choose affects how you’re going to build out the rest of your network.

Lync Enterprise Voice is a VoIP system that utilizes the SIP protocol for session management and routing. You can’t just “plug it in” to a traditional phone service (like a T1 voice line from the phone company) without translating the SIP signal-ing and call data first.

The basic distinction in deployments is how you connect your enterprise to the rest of the world via the PSTN. You have two choices here:

✓ Connect to standard TDM (time division multiplexing) telephone services

Using TDM telephone services can be expensive and isn’t the recommended model.

✓ Connect, via SIP Trunking, directly to an ISP, who then handles any connections to TDM phone networks within its own network infrastructure. You also need a Session Border Controller (SBC) to help secure and control this connection.

There is one other option here for remote branches. You may wish to install a device called a Survivable Branch Appliance (SBA) or Survivable Branch Server (SBS, the difference is in scale — the server is for larger branches) that enables direct connectivity to the PSTN in case the WAN link between that branch and the main office suffers an outage. SBCs, SBAs, and SBSs 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 the enterprise Intranet connection and then on to the PSTN via a gateway or IP-PBX or a SIP Trunk to an ITSP.

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


Lync Enterprise Voice For Dummies, Sonus Special Edition 20is…it depends. Companies that choose SIP Trunking do so because

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

✓ SIP Trunking provides a simpler deployment, with less equipment to buy, manage, and maintain.

✓ SIP Trunking call costs are typically considerably lower than 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 SIP Trunking model, but a few enterprises may choose to main-tain some degree of TDM telephone service. Typically this will be due to a large existing investment in IP gateways, in which case the enterprise may choose to move to SIP Trunking in a slower, incremental approach.

Industry estimates vary widely on the cost savings realized by using SIP Trunking for connection to external networks. About what percentage of cost do you see as actual reductions in expense for SIP Trunks that you have implemented? Check out Figure 3-1. This graph of cost savings from SIP Trunking derives from a recent Sonus sponsored study.

Figure 3-1: Typical SIP Trunking savings.


Chapter 3: Digging into Lync Enterprise Voice 21

Reviewing a Lync Enterprise Voice Case Study

Sonus recently migrated to an enterprise-wide Lync UC deployment, including a transition from disparate voice communications architectures to a unified Lync Enterprise Voice infrastructure.

First some background. The company has major headquarters, technology centers, and branch offices located throughout the world. In 2012, the company acquired a firm that had already recently completed its own migration to Lync and Lync Enterprise Voice. After the acquisition, with the increase in employees and locations as well as the added complexity to the company’s voice communications infrastructure, Sonus struggled to productively and economically provide voice ser-vices to its global employees.

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

Sonus set and met targets to get the entire combined enter-prise up-and-running on Lync messaging, video/voice, and collaboration in just eight weeks and to completely move all communications (including outside-the-enterprise commu-nications via the PSTN) to Lync Enterprise Voice within six more months.

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

✓ Each employee can click-to-call colleagues from IM or e-mail when the colleague’s presence indicated availability.

✓ Global interactive whiteboarding sessions supported by Lync allow coworkers across the country and around the world to collaborate in real time.


Lync Enterprise Voice For Dummies, Sonus Special Edition 22 ✓ Audio conferences for up to 200 people can be set up on

the fly in less than a minute.

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

✓ The company’s CIO noted that employee productiv-ity was measurably improved by the Lync and Lync Enterprise Deployment.

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

✓ Significant savings — approximately $40,000 per office per year — by replacing existing IP gateways with a single 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 to previous disparate systems

✓ Over $200,000 per year saved on conferencing expenses by keeping internal conferences “on network” within the enterprise’s own SIP-based WAN (or Intranet) using Lync

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


Chapter 4

Getting the Most Out of Lync 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)

I n 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 devices that enable that internal Lync to external PSTN calling. First, we introduce Internet Protocol (IP) Gateways and IP-PBX (Private Branch Exchange) devices that are especially designed to translate between SIP VoIP and Time Division Multiplexing (TDM) phone services. We discuss the concept of “survivability” — how to keep the phones on when the worst happens and the survivability-focused hardware that gets installed in smaller branches of an enterprise using Lync Enterprise Voice. You also find out what a Session Border Controller (SBC) is.

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


Lync Enterprise Voice For Dummies, Sonus Special Edition 24An IP gateway can be a standalone, single-purpose device, or it may be part of a multi-purpose device that includes IP gate-way functionality. It will be paired with an SBC for security and media handling functionality.

You may also see IP Gateways referred to as Media Gateways, VoIP Gateways, or PSTN Gateways.

In an enterprise environment, an IP gateway is typically con-nected between an IP-PBX and a TDM-based service provider phone service connection (known as trunk lines). The IP gateway functionality may also be integrated directly into the IP-PBX, where the PBX connects directly to trunk lines.

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

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

For connection to the PSTN, a device that translates between the SIP-based VoIP calls used by Lync Enterprise Voice and the TDM 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 PSTN protocols and signaling. In conjunction with the SBC, the IP Gateway may also help to

✓ Convert transmission and encoding techniques — called transcoding

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

✓ Support the networking protocols on both sides of the gateway — typically this will be Ethernet within the Lync Enterprise Voice network and standard TDM networking protocols such as T1 or E1 on the PSTN side

✓ Maintain “toll-quality” voice quality in calls by supporting features like echo cancellation and low latency (delay) during calls


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

Making Enterprise Voice More Robust with Survivability

For enterprises with more than one location — which is pretty much all medium and large enterprises — there is a design 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 typically depend on a central site for call control and connections to the PSTN because the front- and back-end servers and often the Mediation Server, as well, are located in the central site (usually the main office). So users in branch sites depend on processing that occurs in the central site(s) for their UC connectivity.

The centralized control of the Enterprise Voice network leaves two points of vulnerability:

✓ If there’s a disruption in service to the enterprise WAN connection between the branch and central site, the branch site loses all communications connectivity both within and outside of the enterprise.

✓ If there’s a server outage in the central site, the branch office has network connectivity, but users there are unable to communicate.

In these two instances, you can see that it’s imperative to architect the Enterprise Voice network in such a way that branch sites aren’t left out in the cold.

The main safeguard against these types of outages is the installation of “survivable” equipment in branch sites. This equipment includes Lync Enterprise Voice network gear that can pick up some of the processing and connectivity slack when the worst happens. It’s essential to spend time while architecting the network to make the network more resilient and survivable in the following locations:

✓ Central sites: This process involves building sufficient redundancy into the network. For example, an Enterprise Voice deployment can be made more redundant and resilient by installing backup server pools in other


Lync Enterprise Voice For Dummies, Sonus Special Edition 26locations and then defining failover routes within the network, so services can be seamlessly delivered after failures.

✓ Branch sites: The installation of a Survivable Branch Appliance (SBA) provides the backup processing and PSTN connectivity to keep a branch online during a failure situation. More on SBAs in the later section “Understanding SBAs.”

✓ All sites: The installation of an SBC provides additional security and intelligent routing of calls whatever the net-work status is.

Understanding SBAsIt’s the role of the SBA (and its larger sister, the SBS — Survivable Branch Server) to provide resiliency and survivabil-ity (hey, it’s right in the name!) for Lync Enterprise Voice branch sites. When a branch’s communications are provided through a Lync server in the central site, the loss of WAN connectivity can leave branch offices with neither internal (for example, station-to-station) nor external communications capabilities.

SBAs at each branch office make it possible for those offices to continue to provide basic voice telephony services to employees when network connectivity to the main office is lost. Specifically, an SBA makes this possible by functioning as a local PSTN gateway and providing basic voice telephony services to employees in the branch office. When the connec-tivity to the main office is restored, the branch office reverts back to the original configuration and telephony calls are once again processed by the main office telephony system. Pretty neat trick, huh?

Resiliency and survivability don’t mean that every single Lync service works without a hitch during a central site or WAN outage. Instead, it means that the most essential services stay on 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 and between sites


Chapter 4: Getting the Most Out of Lync Enterprise Voice 27 ✓ Basic IM

✓ Dial-in (PSTN) conferencing

✓ Voice mail

Other services — like E911, web or videoconferencing, and other advanced Lync features — may not be available until the network is fully restored. But enterprise employees can keep 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. Microsoft’s recommendations for when to deploy an SBA/S are as follows:

✓ Branch sites between 25 and 1,000 users should get an SBA.

✓ Branch sites between 1,000 and 2,000 users should deploy 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 to the central site level and deploy Lync server.

Regardless of which approach is taken, a key to resilient branch deployments is the addition of connectivity to exter-nal phone services. To provide this, a branch site can use one of 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 central site 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 handle three key functions:


Lync Enterprise Voice For Dummies, Sonus Special Edition 28 ✓ UC network security and intelligent routing

✓ SBA functionality in case of a network or central site server outage

✓ Connectivity via SIP Trunking to an ITSP (if the branch uses 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-prise’s and the phone company’s networks) and provides all sorts of security and mediation services to keep things run-ning smoothly. It communicates between two network end devices, such as a Lync SIP VoIP call between two phones. These communications are called SIP sessions. The SBC does this session controlling at the point where traffic is handed off from one network to another (called the border) — like where traffic leaves the enterprise and goes onto a service provid-er’s SIP trunks. Because of where the SBC fits in the network, it can be usefully implemented by both businesses themselves and also by the service providers who serve them.


Chapter 4: Getting the Most Out of Lync Enterprise Voice 29Lync Enterprise Voice network operators — both enterprises and service providers — face threats to the security of their network and business and also face more everyday issues such as how to make VoIP work seamlessly and efficiently while also realizing the cost and bandwidth savings that VoIP promises. That’s what makes SBCs really worth deploying in an 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 attempt to overwhelm the network with fake connections.

•Spoofing attacks: Nefarious users attempt to gain access to the network deceptively.

•Toll fraud: Hackers attempt to access the network in order to route calls over it at the network owner’s expense.

✓ Enabling SIP trunking, allowing the network owner to save money and operate more efficiently by connecting directly to an ITSP via SIP trunks

✓ Enabling better communications in varied network envi-ronments

For example, a deployment where existing IP-PBXs and other legacy telephony equipment is integrated with the Enterprise Voice deployment. The SBC is designed to smoothly 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 Lync Enterprise Voice networks.




Chapter 5

Leveraging SBC for Enterprise Voice

In This Chapter▶ Making 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

T he 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 a Lync Enterprise Voice Deployment to ensure interoperability and functionality — sits at the border between the internal Lync Enterprise Voice network and the SIP Trunk service provided by the Internet service provider (ISP) or a legacy Internet 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 how SBCs enable and improve SIP Trunking for connections to ISPs. Then we discuss the role of the SBC in integrating IP-PBXs with a Lync deployment. You also discover how SBCs improve service quality and make E911 services work. Finally, you delve into how SBCs help with multivendor compatibility and central con-trol and troubleshooting of the Enterprise Voice deployment.



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

Connecting to SIP Trunking Services

While some enterprises may use TDM voice services with their Enterprise Voice deployment, a growing number are taking the VoIP revolution to its logical conclusion and partnering with SIP Trunking ISP partners. In a SIP Trunking deployment all calls entering and leaving the enterprise are carried as SIP packets across a data connection — there are no “phone lines” like there are in a TDM deployment (where an enterprise may lease access to a T1 or E1 line with a fixed number of “lines” associated with that transmission facility).

Instead, SIP Trunking uses a standard service provider data connection — which may be shared with other data/Internet services or dedicated to the purpose of SIP Trunking. The enterprise isn’t paying for lines; it’s paying for bandwidth. Any VoIP to PSTN translation that’s required in a SIP Trunking deployment (for connection to “regular phones” outside of the enterprise network) is handled by the ISP. Everything that enters 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 packet crossing between the Lync network and the external ISP network, determining which should be allowed through and how they should be routed.

✓ An interworking role: The SBC allows SIP systems to “talk” to each other even if they speak different “dialects” of SIP. Among the translations that an SBC can perform are

•SIP normalization: SIP is a standard, but there are subtle variants in the way SIP is implemented — the SBC can understand all of them and modify the SIP


Chapter 5: Leveraging SBC for Enterprise Voice 33packets to ensure both ends of the call can get the full 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 devices and different network segment capabilities. For example, a video call may be transrated to a lower bit rate to accommodate an endpoint on a mobile network.

•Transcoding: SBCs can translate — in real time — the codecs (encoding and decoding protocols) used for digitizing and transmitting calls. This can be essential when the endpoint devices involved in a call support different codecs.

✓ Network security: The SBC controls the admission of calls in and out of the enterprise and protects the net-work against denial of service attacks, toll fraud, and other attacks against the Lync Enterprise Voice network. Additionally, the SBC can “hide” the topology of the Lync network within the enterprise, so external parties aren’t able to detect the devices within.

Integrating with Existing IP-PBX Platforms

Many enterprises migrating to Lync Enterprise Voice have an existing base of IP-PBXs already in place, performing the same sorts of call functionality provided by Enterprise Voice. In these cases, most enterprises don’t choose to perform a “rip and replace” wholesale replacement of the existing infrastruc-ture in favor of a Lync Enterprise Voice infrastructure.

Instead, most gradually implement Enterprise Voice while retaining some or all of the IP-PBX infrastructure. In some cases, this will be to leverage the TDM telephony interfaces offered by the IP-PBX, while in other cases, the IP-PBX will stay in service to provide specific services or to serve some segments of the network while others are transitioned to Enterprise Voice.


Lync Enterprise Voice For Dummies, Sonus Special Edition 34The SBC plays a vital intermediation role and can provide SIP normalization, transcoding, and transrating to allow a smooth integration between Enterprise Voice and the IP-PBX.

Most larger enterprises have a disparate IP-PBX base — more than one vendor serving the company with different IP-PBXs in different locations. In these cases, an SBC is even more vital to a smooth integration because it’s likely that each of these different IP-PBXs will have its own SIP variations and trans-coding requirements.

In addition to the SIP normalization and transcoding/rating functions, SBCs also serve to provide a centralized call rout-ing intelligence — located logically “above” both the IP-PBXs and the Lync Enterprise Voice servers. So the SBC can be the brains of the deployment, helping to ensure that calls are routed correctly, with the most efficient use of network resources and the lowest costs.

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

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

✓ Call Admission Control: The SBC decides which calls can be allowed on the Enterprise Voice network — based on customizable policies set up by the enterprise — to keep the network running smoothly during busy call periods.

✓ Transcoding/rating: The SBC can use more efficient codecs when the network’s bandwidth is near capacity.

✓ VoIP prioritization: The SBC can place voice calls higher in the pecking order (over things like video or webconfer-encing) when the network’s capacity is being filled up.


Chapter 5: Leveraging SBC for Enterprise Voice 35 ✓ Media Bypass: Lync supports a process known as

Media Bypass where the Lync Mediation Server can be bypassed. Media Bypass can greatly reduce the load on the Mediation Server, ensuring proper capacity for calls that can’t be bypassed.

✓ Monitoring the network’s health: The SBC monitors bandwidth usage, latency, jitter, and other metrics and then feeds that data back into call admission control and other functions.

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

Just because Lync supports E911 doesn’t mean that it will just work right out of the box though. The SBC can help in a number of scenarios:

✓ For Enterprise Voice deployments connecting via TDM and an IP Gateway, the SBC can support the connection to the appropriate local Emergency Response Location (ERL) and pass along standards-compliant location data — something that Lync can’t do on its own (over a TDM connection).

✓ In a SIP Trunking environment, the SBC supports E911 in two ways:

•Insomecases,theISPmaynotcarrythelocationcomponents of the SIP signal. In these cases, a TDM line may be connected to the SBC, and E911 will operate as discussed in the previous bullet point.

•Inothercases,theISPwill carry the E911 informa-tion but requires a direct SIP trunk connection to the Lync Mediation Server from the 911 service pro-vider — something not all enterprises wish to do for security reasons. The SBC can serve as a proxy between the 911 network and the Lync network, passing all necessary location data, while maintain-ing network separation and security.



Dealing with Interoperability between Vendors

SBCs are really good at playing the role of intermediary between the Lync servers and a SIP trunking provider. The SBC’s ability to normalize SIP and to transcode and transrate media makes it the perfect go-between in any sort of VoIP net-work deployment.

SIP equipment vendors — whether they’re making IP gate-ways, SIP VoIP client devices, or whatever, really — tend to have their own slightly distinct variations of the SIP protocol standard. It’s not like one is speaking English and the other is speaking Mandarin; it’s like one is speaking Australian English while the other grew up in Boston. The words and constructs are the same, but occasionally they can’t quite understand each other.

Many — perhaps even most — Lync Enterprise Voice imple-mentations involve equipment from more than a single vendor. 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 impactful incompatibilities and differences in the way these different devices use SIP. The impact is often missed or dropped calls or just a plain “the network’s not working” type of scenario. Putting the SBC in between these disparate network elements and letting it do what it does best (enabling network inter-working) is the solution.

Centralizing Control and Troubleshooting

Because SBCs sit in a unique place in the Enterprise Voice network — at the edges of the network where voice and other UC traffic transitions between locations and between network borders — they can also play a unique role: that of central control point in the network.


Chapter 5: Leveraging SBC for Enterprise Voice 37The SBC can control the network through its role as call admission control point and through its intelligent call routing capabilities. These functions are governed by robust policy capabilities that let the enterprise or a service provider pro-viding Lync Enterprise Voice determine and enforce centrally established 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 and utilization of each UC network element. That means when it comes time to track down a problem or to optimize policies and network topologies, the SBC can help pinpoint the areas that need attention.




Chapter 6

Ten Reasons to Choose Sonus 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

T he Session Border Controller (SBC) is a key element in securing, controlling, maximizing QoS, and enabling

services (like SIP Trunking and E911) in a Microsoft Lync Enterprise Voice deployment. Sonus Networks is a vendor for SBCs and has a lineup that just may be a great choice for your Enterprise Voice deployment. In this chapter, we give you ten reasons to choose Sonus for Enterprise Voice.

Microsoft Compatibility and Qualification

Sonus is a qualified Microsoft Lync hardware partner and has several 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. It’s one of the faster growing brand of SBCs.



Multivendor InteroperabilitySonus SBCs are deployed throughout the world in a variety of environments, supporting Lync Enterprise Voice and a wide range of IP-PBXs and legacy TDM-PBX systems in different configurations.

Sonus has a broad range of compatibility and interoperability in the industry. So no matter what your legacy situation and no matter how you’re transitioning to Lync Enterprise Voice, Sonus has you covered.

Maximized Resiliency and Protection Against DoS Attacks

Keeping the “lights on” is important in any network environ-ment. In an Enterprise Voice environment it’s critical. Sonus SBCs are designed to provide high availability, enabling calls to be completed even under peak conditions.

For larger deployments, Sonus SBCs can be deployed in pairs (in what’s called Active-Active mode), to provide load balanc-ing and even high availability. Sonus SBCs can additionally balance the call load across multiple Lync Mediation servers to 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 attack can cripple an enterprise’s voice services by simply overload-ing servers with malicious incoming IP traffic.

Sonus SBCs offer sophisticated real-time firewalling and the use of techniques such as Virtual LAN (VLAN) tagging, which drops the malicious packets and allows legitimate traffic to continue 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


Chapter 6: Ten Reasons to Choose Sonus for Enterprise Voice 41deployment. 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 aren’t able to make head or tails of a 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 the SBC — allows real-time encryption processing to take place without 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 make the disruption of an outage a minor rather than a major event.

For example, Sonus SBCs typically include redundant power supplies, so a failure of a power supply can be handled with-out a hitch. And if something external to the SBC causes the outage (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 are up and running. If a failure occurs, the Sonus SBC automatically attempts to find alternate routes to complete calls without the end-user ever knowing that there’s a problem. In branch sites, the Sonus SBC can automatically reroute calls to the PSTN (or even 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 full Lync Enhanced SBA with 3G/4G failover capability. So an enterprise’s branch sites get high-quality voice services, ready-to-go survivability and require one less device in the


Lync Enterprise Voice For Dummies, Sonus Special Edition 42network — that makes the network simpler and cheaper to provision 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 sent to all locations with one action, which means lower expenses for IT and better/faster results for users. This streamlining also eliminates the need to hire or send expensive IT technologists to each location in the network to maintain and update policies.

Exceptional Transcoding Performance

Often voice calls aren’t in the same codec, such as when in languages a translator or in UC a transcoder is needed to con-vert between the two. The Sonus SBC platform has a separate processing architecture of media transcoding and transrat-ing, so the overall performance of the SBC doesn’t take a “hit” when a lot of processor-intensive transcoding is going on. Whatever the transcoding load, the encryption/security and the routing modules are unaffected.

Additionally, this functionally separated architecture makes it easier and less expensive to add more processing power for a specific function without requiring the enterprise or service provider to upgrade other parts of the SBC that are adequately provisioned.

Wide-Ranging Media SupportSonus SBCs provide a wide range of support for different media types because it doesn’t rely on off-the-shelf solutions (with its generic off-the-shelf software) for media processing. Instead, Sonus creates its own firmware, which allows Sonus to responsively add additional media types as needed without waiting for a vendor to come along with a solution.


Documents

Lync® Enterprise Voice For Dummies®, Sonus Special Edition