These materials are © 2015 John Wiley & Sons, Inc. Any ... Skype for...These materials are 1 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthoried use is strictly

These materials are © 2015 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited.


Skype for Business

By Brad Chapin and Kevin Isacks

Sonus Special Edition


Skype for Business For Dummies®, Sonus Special EditionPublished by John Wiley & Sons, Inc. 111 River St. Hoboken, NJ 07030‐5774 www.wiley.com

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Table of ContentsForeword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1About This Book ........................................................................ 2Icons Used in This Book ............................................................ 2

Chapter 1: What Is Unified Communications? . . . . . . . . .3Understanding UC ...................................................................... 4Taking a Closer Look at UC Applications ................................ 5Getting Started with UC ............................................................. 6

Chapter 2: Getting to Know Skype for Business . . . . . . .9Is “Skype for Business” an Oxymoron? ................................. 10Skype for Business Server 2015 ............................................. 10Skype for Business Client App ............................................... 11What’s Included with Skype for Business? ........................... 12How Do I Deploy Skype for Business? ................................... 14

Deploying Skype for Business in your data center .................................................... 14

Skype for Business in Office 365 .................................. 15Deploying Skype for Business

as a hybrid solution ................................................... 15Are Other Companies Really Betting Their

Communications on Skype for Business? ......................... 16

Chapter 3: Shining the Spotlight on Skype for Business Enterprise Voice . . . . . . . . . . . . .17

What Is Skype for Business Enterprise Voice? ..................... 18Looking into Skype for Business Enterprise

Voice Features ...................................................................... 18Making Skype for Business Enterprise Voice Work ............. 20Planning for Deployment ........................................................ 20

Different deployment models ....................................... 21Choosing a deployment model .................................... 22

Enterprise Voice in the Real World: A Case Study .............. 23

Skype for Business For Dummies, Sonus Special Edition ________iv


Chapter 4: Getting the Most Out of Skype for Business Enterprise Voice . . . . . . . . . . . . .25

IP Gateways and IP PBXs......................................................... 25Making Enterprise Voice More Robust

with Survivability ................................................................. 27Understanding SBAs ................................................................ 28

Chapter 5: Improving Enterprise Voice Quality, Security, and Reliability with an SBC . . . . . . . . . . . . .31

Introducing the SBC ................................................................. 32Connecting to SIP Trunking Services .................................... 33Integrating with Existing IP PBX Platforms ........................... 34Ensuring Quality of Service .................................................... 36Supporting E911 ....................................................................... 36Dealing with Interoperability between Vendors .................. 37Centralizing Control and Troubleshooting ........................... 38

Chapter 6: Ten Reasons to Choose Sonus . . . . . . . . . . . .39Microsoft Compatibility and Qualification ........................... 39Multivendor Interoperability .................................................. 40Maximum Resiliency and Protection against

DoS Attacks ........................................................................... 40Encrypted Communications ................................................... 40Rapid Recovery ........................................................................ 41Survivability for Branch Sites ................................................. 41Virtually Ready for the Cloud ................................................. 41Centralized Policy Management............................................. 42Exceptional Transcoding Performance ................................. 42Wide‐Ranging Media Support ................................................. 42


Foreword

O ver the past few years, for many organizations the search for the next technology that can deliver strategic advan-

tages is leading to Unified Communications (UC) and to Microsoft Skype for Business (formerly Lync) as a critical component. Analysis shows that in North America as many as 70 percent of enterprises are adopting this solution for at least some of their users. Skype for Business (referred to here as SkypeB) delivers a unique set of capabilities to integrate com-munication modalities, presence, application integration, and other services. With SkypeB, organizations can streamline business processes and increase productivity by assuring that the right communications happen at the right time, with the right people, and the right tools to assure successful out-comes. While most SkypeB deployments start as an internal trial and then deployment, many organizations rapidly find that extending SkypeB beyond the boundaries of the organiza-tion can yield equal or even greater benefits than internal use alone. By using SkypeB federation and integration to the con-sumer version of Skype, the capabilities of SkypeB can be extended to partners and customers, reducing costs and increasing business success. Using SkypeB conferencing can reduce conferencing costs and when combined with SkypeB telephony services can deliver a truly unified user experience. It also has the potential of reducing the cost of supporting tra-ditional legacy telephony equipment. All of this leads to SkypeB Enterprise Voice as a logical extension of any SkypeB deployment.

Having a plan to support SkypeB Enterprise Voice should not be left as a future activity; it should be planned for early and with deliberation. One key element of a successful external SkypeB deployment is a Session Border Controller (SBC) that can manage and assure the security and integrity of the organi-zation, so Sonus sponsoring this guide is a logical extension of their SkypeB focus. With SkypeB externalization, doors are opened to a new set of threats, both external and internal, deliberate and unintentional, that can have significant impact. Also, an SBC enables the organization to take full advantage of the revolution in SIP trunking to reduce costs and manage

Skype for Business For Dummies, Sonus Special Edition ________vi


multiple service providers through a single platform. This book is a guide to begin to understand the issues and complex-ity of a SkypeB Enterprise Voice deployment. It gives the reader the understanding to begin the process of making the right decisions to assure both personal, and organizational success with SkypeB Enterprise Voice.

Phil Edholm

PKE Consulting LLC & UCStrategies.com

[email protected]

www.pkeconsulting.com

mailto:[email protected]


Introduction

T elecommunications is always evolving. And so it was inevitable that the Public Switched Telephone Network

(PSTN) would eventually embrace elements of that other big network, the Internet. Where the PSTN originally used a protocol known as Time Division Multiplexing (TDM) to transport digitized voice traffic, the Internet required a different protocol, and so Voice over Internet Protocol (VoIP) was created.

Because VoIP uses the same protocol as other Internet traffic, it wasn’t long before enterprising companies began to com-bine VoIP with IP‐based services such as instant messaging (IM) and video to create richer communications services. If you’ve ever clicked on a web page to launch a voice call or viewed a webinar where someone was sharing his or her desktop, you’ve used these services.

Adding VoIP to the digital conversation makes a lot of sense, but the reality is that managing voice and video and email and texting and the sundry other services out there can be a lot of work. By some estimates, the average knowledge worker spends up to 2.5 hours per day just managing all these con-versations via email, voicemail, and so on. What businesses really need is a way to unify all these communications in one place so their employees don’t have to spend so much time managing different services. And thus the concept for Unified Communications (UC) was born.

UC platforms combine voice, video, email, instant messaging (IM), and other communications services in a single applica-tion, on a single screen that can be managed consistently across multiple devices such as laptops, smartphones, and tablets. Yes, it saves time and money, but more importantly, it allows business users to collaborate more effectively.

Skype for Business For Dummies, Sonus Special Edition ________2


About This BookThe most recent example of the evolution of telecommunica-tions is the introduction of Microsoft’s Skype for Business. Previously known as Microsoft Lync (and several other names before that), Skype for Business inherits the role as the de facto standard for UC at thousands of enterprises around the world. For loyal Lync users, the transition will be a seamless one — as it stands today, the name change is arguably the most significant difference between the two products. Skype for Business still includes all the functionality that made Lync popular with enterprises, and it incorporates some new fea-tures that showcase Skype’s reputation for simplicity and, more importantly, connectivity to millions of Skype users around the globe.

This book explains what’s new in Skype for Business, with special attention paid to the Enterprise Voice component of Skype for Business. You discover how it works, what it requires in terms of integration and security, and how to get the most value from it in your enterprise.

Icons Used in This BookThroughout this book, you may notice four different types of icons that appear in the left margin.

The Tip icon identifies time-savers (and the occasional life-saver) for people planning to deploy Skype for Business in their company.

The Remember icon alerts you to useful information that will come in handy later.

Watch out! This icon warns you against potential pitfalls and mistakes that, um, other companies learned the hard way (okay, so maybe we learned some of them that way).

This icon indicates that you’re entering the weeds (we are, after all, techies at heart), but you can skip over them if you left your acronym decoder ring at home without missing anything important.


What Is Unified Communications?

In This Chapter ▶ Getting a handle on UC

▶ Understanding the world of UC applications

▶ Knowing what it takes to make a UC solution

U nified Communications (UC) has been called a “PBX killer,” which begs the question: What exactly is a PBX?

It stands for Private Branch Exchange, and you can think of it as the collective brain for your business phones. Desk phones are, generally speaking, “dumb” devices. They don’t know how to forward calls to your voicemail or handle a conference call; in fact, they don’t even know when someone is calling you. All those “intelligent” phone tasks are handled by a PBX, usually for dozens or even hundreds of phones.

PBXs have been around for decades. They’re typically com-plex machines to program, costly to maintain, and a large enterprise may have to manage dozens (or more) of them. Oh, and did we mention that PBXs from different vendors or even different models from the same vendor often don’t com-municate well with each other? No wonder enterprises want to replace them.

UC applications such as Skype for Business provide that same phone intelligence but in a software‐based solution. Instead of dozens of expensive gray boxes, enterprises can provide all the intelligent phone features they need (call forward-ing, voicemail, direct inward dialing, and so on) through a

Chapter 1



centralized server running the Skype for Business application. Of course, you also need a few other components, including a SIP trunk connection and a Session Border Controller (SBC) to enable and secure VoIP using Skype for Business, but the cost and complexity is much lower than with a traditional PBX system. Figure 1-1 shows how this all fits together.

Understanding UCUC represents the next generation of enterprise communica-tions and collaboration technologies, bringing multiple com-munications applications under a single architecture. This allows for seamless communications across applications, no matter where you are or what device you use. These com-munications can be delivered over an Internet Protocol (IP) network through the following mechanisms:

✓ Voice applications, including person‐to‐person calls, voicemails, and multiparty conference calls

✓ Video applications, including videoconferencing and on‐demand video learning

✓ Data applications, including text messaging, email, and document sharing

The unified part of UC refers to the fact that the UC hard-ware and software take all these applications and put them under the management of a common control system, instead of using different hardware and software solutions for each

Figure 1-1: The Microsoft Skype for Business solution.

��Chapter 1: What Is Unified Communications? 5


individual application. This provides two big benefits to enterprises:

✓ It allows communications to be delivered across different media. For example, a voicemail could be retrieved as an email attachment or even as a speech‐to‐text translated message.

✓ It applies presence and location information to communi-cations so they can be routed and delivered more intelli-gently. For example, a voice call might go directly to your mobile phone if you’re out of the office.

Presence refers to an individual’s current communications status (for example, available, busy, do not disturb). This will be familiar to IM users as well as commercial Skype users because both have made use of presence features in their communications for some time. In UC, presence is a richer bit of data that, when combined with location information, helps the UC system figure out how and when to deliver your com-munications to you. For example, if your status shows that you’re in a meeting, a UC system may route calls directly to your mobile device without trying to ring the phone.

This combination of multiple platforms, clients, and com-munications methods with presence and location data is a powerful tool. It can greatly streamline and improve the ways that enterprise employees communicate, coordinate, and col-laborate with each other — whether they’re in the same office building or in different hemispheres!

Taking a Closer Look at UC Applications

We briefly touch on the basic kinds of UC applications (voice, video, data) in the preceding section, but in this section, you take a closer look at what UC platforms typically have to offer:

✓ Voice calls: UC systems provide VoIP‐based person‐to‐person or multiparty voice calls using a standard phone, PC, laptop, smartphone, or tablet. With UC, users no longer need a PBX system (or the PSTN) to make voice calls, which can save businesses a lot of money.



✓ Instant messaging (IM): UC systems provide person‐to‐person and multiparty IM sessions, often with the addition of features such as persistent chat sessions, continuous sessions across multiple devices, and the capability to resume sessions at a later time.

✓ Videoconferencing: UC supports high‐quality (often high‐definition) 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 enterprise solution. 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 do this, you need a working data connection on the mobile device and a UC app installed on the device (your IT department can install the app or you can do it directly through an app store).

Getting Started with UCBeyond the UC solution itself, you need several pieces to com-plete the UC picture. These include

✓ Connectivity to an IP network, typically via a SIP trunk

✓ A server (or servers) to run the UC applications and provide back‐end functionality, such as directory or contact servers, presence data, and so on

✓ UC clients on the end‐user devices (either desktop or mobile devices)

✓ Edge devices deployed at the network border (such as an SBC) to control, secure, and optimize communications to/from your network

UC can be deployed in a variety of ways:

✓ Enterprise deployments in which the servers and soft-ware reside on premise (typically in a data center or server room), which are owned and operated by the enterprise

��Chapter 1: What Is Unified Communications? 7


✓ Hosted deployments offered by a third‐party service provider

(In this case, the third‐party service provider typically manages the servers and operations for a fixed monthly fee.)

✓ Hybrid deployments featuring a mix of premise‐based and hosted functionality, such as instances where an enterprise may want to keep its videoconferencing ser-vices on a secure but external server

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 the IP bandwidth for voice, video, and data communications and, in most cases, connectivity to the PSTN as well.




Chapter 2

Getting to Know Skype for Business

In This Chapter ▶ Introducing Skype for Business

▶ Looking at Skype for Business Server 2015 and Client App

▶ Knowing what’s included in Skype for Business

▶ Understanding different deployment options

▶ Taking a look at what’s driving the adoption of Skype for Business

I n 2014, Microsoft announced that Lync 2013 would be rebranded as Skype for Business, causing millions of

Lync users to wonder what the change would mean for them. Would Skype for Business still deliver the same robust, enterprise‐class capabilities? Would it be more open, less secure, cheaper, or more expensive? Would it even be compatible with Lync 2013?

The answer out of Redmond, Washington, has been reassuring: Skype for Business still delivers all the great things users love about Lync, plus a few new tricks learned from millions of Skype users (such as a simpler user interface). And, yes, Skype for Business will integrate with and upgrade seam-lessly with Lync 2013, so you don’t need to trade in your Lync licenses just yet.

In this chapter, we introduce you to Skype for Business, discuss the different deployment scenarios, and highlight the applications that Skype for Business supports.



Is “Skype for Business” an Oxymoron?

Skype is one of the most popular consumer apps in the world, but it has never been synonymous with business. Originally, people “Skyped” to save money, enjoy rich voice and video calls, and connect to friends simply and easily from any device. Which, when you think about, is exactly what enter-prise users are doing with Lync.

In fact, the rebranding makes a lot of sense when you factor in the power of the Skype brand. Skype is simple, it’s cost‐effective, and it’s robust. It’s a lot of the things that you’d want in a Unified Communications (UC) experience. Lync fills in the gaps: It’s secure, it supports all kinds of different platforms and devices, and it has enterprise‐class features such as desktop sharing and unified messaging. With that in mind, Skype for Business promises to be the best of both worlds: simple enough for consumers but strong enough for enterprises.

Sounds cool, right? So what do you need to get started? Skype for Business remains a UC platform, and UC platforms require two key components:

✓ A server to run the UC software and host UC services

✓ A client app on the device that plans to use these UC services

Skype for Business includes both the server software (called Skype for Business Server 2015) and the client software (the Skype for Business App). Like Lync before it, Skype for Business can run on a single server instance, support dozens of different devices (PCs, laptops, IP phones, smartphones, and tablets), and be deployed on premise or hosted in the Cloud through a service provider.

Skype for Business Server 2015The Skype for Business Server 2015 software is designed to provide the following services to an enterprise:

�� Chapter 2: Getting to Know Skype for Business 11


✓ Instant messaging (IM) and presence applications: This works both for internal employees and external customers/partners. Skype for Business supports most standard Internet IM systems, including Lync, Windows Live, Yahoo! Messenger, AOL IM, and Google Talk.

✓ Videoconferencing: This application allows users to share screens and files, enjoy collaboration, manage voice and chat (IM) meetings, and conduct virtual meetings anytime, anywhere, on any device.

✓ Enterprise VoIP: This application supports both person‐to‐person and multiparty (such as conference) calls. As with Lync before it, Skype for Business Enterprise Voice delivers a rich set of PBX‐styled services, including voice-mail, call holding, call forwarding, and many more.

✓ Connectivity via SIP trunks or the PSTN: This enables enterprises to purchase voice services from an ISP and ITSP via SIP trunks or through a traditional telephony provider via PRI trunks (for example, the PSTN).

✓ Seamless support for remote and mobile users: This service includes branch offices, telecommuters, and at‐home workers.

Many others services exist, too. This list is way too long to include here, so for a complete list, which includes support for dozens of additional apps and services, you can visit Microsoft’s website.

Skype for Business uses the industry‐standard protocol for high‐quality, real‐time communications over the Internet, Session Initiation Protocol (SIP). SIP not only helps ensure that real‐time media such as voice and video have the requisite quality and security but also enables applications to mix and match differ-ent kinds of communications (for example, voice, video, IM) in the same session, so users can switch from an IM chat to a voice call without ending the session. SIP also ensures that devices and applications speak the same language (refer to Chapter 1’s discussion of PBXs to see why that’s a good idea).

Skype for Business Client AppIn addition to a server, most UC platforms (including Skype for Business) require a client‐side app on the end‐user’s device that interfaces with the server. Several different kinds



of client apps are available (do an online search) with Skype for Business, based on the type of device:

✓ PC/laptop software client: This is the primary way that most people use Skype for Business. The Skype for Business client software enables PCs and laptops to support and manage multiple types of communications, including IM, presence, video, collaborative tools, and even voice calls.

✓ Mobile app: Skype for Business can be downloaded as an app on mobile devices such as smartphones and tablets. Skype for Business supports most major mobile operat-ing systems, including Windows Mobile, Android, and Apple’s iOS.

✓ Web‐based client: Users aren’t required to load a client app on their devices to use Skype for Business. Skype for Business supports full‐featured client access via a web browser interface. All that’s needed is an HTML 5‐compliant browser such as the ones you find in the latest versions of Internet Explorer, Safari, Chrome, and Mozilla.

✓ Skype‐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 can also be used with the Skype for Business platform.

What’s Included with Skype for Business?

Skype for Business is a complete UC platform that includes the following components:

✓ Telephony: Skype for Business Enterprise Voice is designed to replace your existing PBX system. It allows business users to make VoIP and standard PSTN calls and includes audioconferencing, call forwarding and transfer, voicemail, and much more. Deployed in conjunction with SIP trunks, Skype for Business Enterprise Voice can also save you a lot of money versus traditional PBX/PSTN telephony.



✓ IM and presence: Using their Skype for Business clients on a PC or mobile device, business users can set their presence and engage in real‐time and persistent IM chat sessions with one or many users at a time. Clients can also be configured to chat with other Skype users outside the business or use standard Internet IM protocols to chat with users anywhere on the web.

✓ Videoconferencing: Users can conduct HD‐quality video-conferences with up to five users at a time to conduct vir-tual meetings anytime and anywhere and on any device (including mobile).

✓ Meetings: Beyond video, Skype for Business users can quickly (with one click in most cases) conduct collab-orative meetings, including screen sharing, PowerPoint sharing, and other application sharing. Users outside of the enterprise (clients and partners) can be included by using a simple URL and the Skype for Business web client.

What’s new in Skype for Business?Skype for Business is the next iteration of Microsoft Lync 2013. As such, it fea-tures all the functionality announced with Lync 2013 plus some new fea-tures designed to make the solution easier to use and more robust:

✓ A Skype‐inspired user interface that promises to be more intui-tive and easy to use

✓ Broader interoperability with millions of existing Skype users, including Skype‐to‐Skype‐for‐Business voice and video calls,

plus IM and presence compat-ibility between Skype and Skype for Business users

✓ The capability to directly add Skype buddy lists to Skype for Business clients

✓ Video interoperability with more devices

✓ Simple upgrade options that allow Lync 2013 users to seam-lessly transition to Skype for Business



How Do I Deploy Skype for Business?

Businesses can choose to deploy Skype for Business in three ways: They can opt to buy it and install it in their own data center, they can purchase it as a hosted service (sometimes known as UC as a Service or UCaaS), or they can combine premise‐based and hosted services in a hybrid solution.

Deploying Skype for Business in your data centerThe first and perhaps most familiar option for enterprises is to install and manage the UC platform in their own data center. Deploying Skype for Business in your data center may require several different types of servers, depending on the size and complexity of your network.

The following server functions can be deployed on a single, shared server or distributed across distinct servers for greater redundancy, reliability, and capacity:

✓ Front-end and back-end servers: These are the basic, must‐have servers for any Skype for Business deploy-ment. The front‐end server (or servers, in a larger deployment) handles user authentication, presence infor-mation, contact and address book functionality, and the delivery of applications. The back‐end server hosts the data that drives the front‐end servers.

For Lync 2013, Microsoft also offered a Lync Standard Edition Server designed for smaller deployments. This version combined the front‐ and back‐end servers within a single device, but it lacked the redundancy and high availability of a distributed server solution, making it less than ideal for larger, mission‐critical UC deployments. It’s unclear at this juncture if a similar product is planned as part of Skype for Business.

✓ Edge servers: For enterprises offering UC services to mobile or remote users (for example, branch offices, telecommuters, road warriors), an edge server is needed. This would be located in the demilitarized zone (DMZ) outside of the corporate firewall.



✓ Mediation server: Businesses that are replacing a tra-ditional PBX service with Skype for Business Enterprise Voice may need a mediation server to handle the signal-ing interworking, media translation, routing, and other roles. This server can be co‐located on the front‐end server or reside on a dedicated server.

✓ Other servers: Optionally, additional server types may be required, based on the range of services, scale, and complexity of a given deployment.

Skype for Business in Office 365Not every enterprise will have the interest or the expertise to install, manage, and maintain its UC platform on its premises. For these enterprises, Microsoft offers Skype for Business as a hosted, Cloud‐based service.

Skype for Business in Office 365 provides the same robust UC experience but as a managed service delivered over a secure Internet connection. In this scenario, a third‐party host (typi-cally a hosted VoIP provider or even Microsoft itself) owns and manages the Skype for Business Server 2015 environment, and enterprise users simply access their applications through their standard Skype for Business clients as they would normally do.

While the experience is largely the same to users, it’s worth noting that this Cloud‐based version of Skype for Business currently doesn’t offer an Enterprise Voice option, so it’s not designed to replace your existing PBX system. (See Chapter 3 for more on Skype for Business Enterprise Voice features.)

Deploying Skype for Business as a hybrid solutionEnterprises are increasingly interested in hybrid Cloud deployments as a way to reduce costs and increase capacity. Skype for Business can be deployed in a hybrid environment; for example, enterprises may decide to keep core communi-cations capabilities on a premise‐based Skype for Business Server 2015 in their data center, while moving other function-ality into a Skype for Business in Office 365 implementation. This arrangement can be especially useful for enterprises that need to scale out capacity for certain applications quickly,



such as company‐wide conference calls where everyone is using the same service at the same time.

A hybrid deployment can also be advantageous for enter-prises that wish to maintain existing PBX voice services while utilizing Skype for Business in Office 365 for other UC services such as IM and conferencing, or gradually migrate from an on‐premise system to a hosted Skype for Business deployment.

So which deployment is right for you? It depends largely on what you need Skype for Business to do. If you’re looking to replace your current PBX/voice capabilities, you need to go with a premise‐based or hybrid deployment. If, however, you’re just looking to augment your current voice capabilities with IM and conferencing capabilities, Skype for Business in Office 365 could be the answer.

Are Other Companies Really Betting Their Communications on Skype for Business?

In a word, yes. Millions of people are already Lync’d into UC and, frankly, loving it. Industry research shows that more than half of all Lync deployments include Lync Enterprise Voice, showing that companies aren’t afraid to replace their PBXs with a simpli-fied UC solution. As Skype for Business brings the Lync product into the future and into the public Cloud, millions more will likely make the leap as well, and for some very good reasons:

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

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

✓ Skype for Business’ focus on security is a major plus for many enterprises (we talk more about that in Chapters 4, 5, and 6).

✓ Skype for Business offers broad compatibility, such as support for third‐party network hardware and third‐party IM and conferencing applications.


Shining the Spotlight on Skype for Business

Enterprise VoiceIn This Chapter

▶ Getting to know Skype for Business Enterprise Voice

▶ Learning how to effectively deploy Skype for Business Enterprise Voice

▶ Studying a real‐world case study of Enterprise Voice in action

E nterprise voice systems traditionally rely on a Private Branch Exchange (PBX) to provide essential voice func

tions such as conference calling, extension dialing (for example, desk‐to‐desk calling), music on hold, auto attendants, and so on. Skype for Business Enterprise Voice provides those same PBX features and many others, enabling enterprises to seamlessly and easily transition from a legacy PBX system to a Unified Communications (UC) system.

In its most basic implementation, Skype for Business provides enterprise users with instant messaging (IM), presence, and the capability to conduct meetings via voice, video, and collaboration software. The basic Skype for Business implementation, however, doesn’t provide all the voice communication capabilities that a PBX system can provide. As a result, communications remain siloed in two distinct systems: one for users who use Skype for Business and another for those who use the PBX (most often through their desk phones).

Chapter 3



Skype for Business Enterprise Voice augments these basic Skype for Business capabilities with full PBX‐like functionality, creating a single, unified platform for all of an enterprise’s communications needs.

What Is Skype for Business Enterprise Voice?

The basic Skype for Business implementation does feature basic voice capabilities, which includes making internal and external voice calls to Skype/Lync users or other web‐based clients. But that’s only a small subset of an enterprise’s voice communications needs.

Think of the differences between a VoIP‐enabled IM client running on your home PC and a monthly phone service offered by your telco or cable provider. 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 such as call forwarding, hold, and transfer. That’s kind of the difference between Skype for Business in its basic form and Skype for Business Enterprise Voice.

What Skype for Business Enterprise Voice does, in a nutshell, is bring the full‐fledged enterprise PBX experience under the umbrella of the Skype for Business platform. An enterprise can use Skype for Business Enterprise Voice to supplement its PBX or completely replace it.

Looking into Skype for Business Enterprise Voice Features

Whether you’re currently using an older analog or digital PBX or a newer IP PBX system, Skype for Business Enterprise Voice delivers the same PBX features and brings them

��Chapter 3: Shining the Spotlight on Skype for Business 19


into the UC environment for simpler control and ease of use, including:

✓ Connectivity to the PSTN: Enterprise users can call any number, anywhere (within the policy limits of the enterprise, of course — no calls to Antarctica!) when they connect their UC platform to the Public Switched Telephone Network (PSTN) via a gateway or a SIP trunking connection. (We talk more about this in Chapter 4, “Getting the Most Out of Skype for Business Enterprise Voice.”)

✓ Voice calls from anywhere: Users can place and receive calls from any device, in any location, through the Skype for Business client application.

✓ Device switching: With Skype for Business Enterprise Voice, users can switch devices (for example, from a headset on your PC to a conference room phone) with no interruption. This feature is also referred to as call parking.

✓ Call handling: Users can forward calls to a different number, send them to voicemail, or route them to their mobile phone.

✓ Simultaneous ring: Incoming calls can ring on any or all your devices, so calls are never missed.

✓ Team calling and delegation: Users can configure calls to ring on team members’ phones/devices or forward them to an assistant.

✓ Common area phones/hot‐desking: Users can forward calls to specific phones/devices located in shared areas, such as conference rooms or shared work spaces.

✓ Caller ID manipulation: Users can have a different outbound caller ID — for example, showing the main number for an enterprise location rather than an individual phone number.

✓ E911: Skype for Business Enterprise Voice provides location information on calls to emergency services (such as 911) over the PSTN.



Making Skype for Business Enterprise Voice Work

In order to enable all the PBX‐like functionality offered by Skype for Business Enterprise Voice, you need a few additional components in your network:

✓ A Skype for Business Enterprise Voice Mediation Server, which we introduce briefly in Chapter 2

✓ A device or service to connect your Skype for Business Enterprise Voice solution to the PSTN, which we cover in more detail later in this chapter under “Different deployment models”

✓ Additional servers to support various applications, users, redundancy, and disaster recovery as needed

Planning for DeploymentIn order to successfully deploy Skype for Business Enterprise Voice, your technical team first needs to plan the deployment, which includes identifying the policies and configurations for your deployment as well as the underlying network facilities that your deployment requires.

The Skype for Business Enterprise Voice server software includes a Topology Builder module that you can use to validate the network deployment when you’re ready to install Skype for Business Enterprise Voice.

As part of the deployment planning phase, you should consider the following:

✓ Figure out the number and types of sites you want to deploy. Skype for Business Enterprise Voice supports two kinds of sites:

• Central sites: Major offices where you deploy a front‐end server (see Chapter 2 for more on this)



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

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

✓ Estimate how much bandwidth you’ll need between sites from your enterprise’s data wide area network (WAN).

✓ Understand your requirements for survivability, high availability, and disaster recovery because these will drive both bandwidth and server requirements.

Different deployment modelsPerhaps the biggest decision you need to make when planning a Skype for Business Enterprise Voice deployment is how you’re going to handle the offload of voice calls from your network to the PSTN. Skype for Business gives you several options for PSTN interconnection — via Time Division Multiplexing (TDM) or SIP trunking — and your choice affects how you’re going to build out the rest of your network.

The Cloud version of Skype for Business doesn’t provide the full Enterprise Voice functionality you need to replace your PBX systems.

Because Skype for Business Enterprise Voice is a VoIP system that utilizes the SIP protocol for session management and routing, you can’t simply “plug it in” to a traditional phone service like a T1 voice line from the phone company without first translating the SIP signaling and call data.

The basic distinction between SIP and TDM trunking deployments lies in how you connect your enterprise to the rest of the world (for example, the PSTN). Your two choices are

✓ Connect to standard TDM telephone services: Using TDM telephone services can be expensive and isn’t the recommended model.



✓ Connect directly to an Internet Service Provider (ISP) via SIP trunking and let the ISP handle any connec-tions to TDM phone networks within its own network infrastructure: You also need a Session Border Controller (SBC) to help secure and control this connection.

Additional options do exist for connecting remote branches: a Survivable Branch Appliance (SBA) or Survivable Branch Server (SBS). The difference is in scale — the server is for larger branches. An SBA or SBS provides 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.)

Choosing a deployment modelSo which deployment model — traditional TDM telephone service or SIP trunking — is best for an enterprise? For many, SIP trunking will be the winner because it provides some clear‐cut benefits:

✓ Consolidation of PSTN connectivity into a single, central site

✓ A simpler deployment, with less equipment to buy, manage, and maintain

✓ Lower cost per call than TDM‐based services and — in the case of ITSPs that charge by bandwidth only — a complete elimination of per‐minute charges

This may seem like a slam‐dunk case for deploying a SIP trunking model, but some enterprises may still opt to maintain TDM telephone service, often due to either a large existing investment in IP gateways or the unavailability of SIP trunking in their office locations. In such cases, enterprises may wish to get more value from their gateway investments and move to SIP trunking in a slower and incremental fashion.

Industry estimates vary widely on the cost savings realized by using SIP trunking for connection to external networks. Figure 31 shows how much money can be saved as a percentage of costs, based on research from a recent Sonus‐sponsored study.



Enterprise Voice in the Real World: A Case Study

In 2012, Sonus embarked on its own enterprise voice journey, implementing Lync Enterprise Voice (which is being evolved to Skype for Business Enterprise Voice) across its worldwide, multi‐office enterprise. The move was preceded by the acquisition of a new company in 2012 located on the West Coast, creating a bi‐coastal core of operations for Sonus and its employees. Sonus faced many of the common post‐merger challenges, including a new influx of employees and added complexity to the company’s communications infrastructure.

Fortunately, the West Coast division had recently moved to a Microsoft UC platform prior to the acquisition, which provided a UC foundation on which Sonus could build. Within eight weeks, Sonus moved all its messaging, voice, video, and collaboration and completely migrated its entire Enterprise Voice platform to Lync Enterprise Voice a few months later.

Figure 3-1: Typical SIP trunking savings.



In order to support the migration to Microsoft Lync and Lync Enterprise Voice, Sonus replaced numerous IP gateways with a single Sonus SBC with SBA capabilities in each office. Functionally, the migration to Lync and Lync Enterprise Voice provided a new set of productivity advantages for the company:

✓ Each employee could now click‐to‐call colleagues from IM or email instantly.

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

✓ Audio conferences for up to 250 people could be set up on the fly in less than 60 seconds.

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

✓ Employee productivity rose measurably after the Lync and Lync Enterprise Voice deployments.

In addition to added productivity, the company has already seen a nearly 200 percent return on investment (ROI) from the following cost reductions:

✓ Approximately $40,000 per office/per year savings by replacing multiple voice gateways with a single SBC in each branch office

✓ A savings of $150,000 per year in operational expenses (OpEx) due to the simplified management of a unified Lync platform versus managing disparate, multivendor systems

✓ Over $200,000 per year saved by internally hosting telecom services on Lync and using the SIP‐based WAN to route long‐distance calls

✓ An estimated $250,000 reduction in capital expenditures (CapEx) from the existing telecom network over the next several years

One additional point worth noting: These savings occurred while the enterprise saw a substantial increase (over 50 percent) in conferencing minutes after the Lync solution was deployed.


Chapter 4

Getting the Most Out of Skype for Business

Enterprise VoiceIn This Chapter

▶ Seeing the role of IP PBXs and IP Gateways

▶ Understanding Enterprise Voice Survivability

▶ Introducing the Survivable Branch Appliance (SBA)

I n Chapter 3, we discuss which elements are needed to incorporate enterprise voice functionality in a Skype for

Business deployment. In this chapter, you discover the network devices that enable the internal Skype for Business Enterprise Voice system to connect with and make calls on the PSTN. These devices include Internet Protocol (IP) Gateways and IP PBX devices specifically designed to translate between the SIP VoIP system used by Skype for Business and the Time Division Multiplexing (TDM) system used by the PSTN. We also cover the concept of “survivability” in enterprise voice — that is, how to keep the phone service up even when the network goes out.

IP Gateways and IP PBXsIn order to connect Skype for Business Enterprise Voice to the PSTN, you need to first connect to an IP Gateway or IP PBX with integrated IP Gateway functionality that connects to a TDM‐based service provider. An IP Gateway can be a stand-alone, single‐purpose device, or it may be part of a multi‐purpose device that includes IP Gateway functionality.



In some cases, it may be combined with a Session Border Controller (SBC) that also delivers security and media han-dling 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 network; this connection is referred to as a trunk line. The IP Gateway functionality may also be integrated directly into the IP PBX; in this case, the IP PBX would connect directly to the trunk line.

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

Not every IP Gateway or IP PBX is compatible with Skype for Business Enterprise Voice. For a list of certified compatible gear, visit Microsoft’s website.

In order to send and receive calls over the PSTN using Skype for Business, you need a device that “translates” between the differ-ent signaling and media languages used by SIP and TDM. The IP Gateway and, in some cases, the IP PBX can fulfill this role. (An SBC, as we cover in Chapter 5, can also be used for this role.)

IP Gateways have one primary function: to support connec-tivity and conversion between VoIP and PSTN protocols and signaling. In combination with an SBC, the IP Gateway can also help with the following:

✓ Converting transmission and encoding techniques, a process known as transcoding

✓ Supporting signaling protocols for both sides of the conversion (SIP on the IP side, TDM on the PSTN side)

✓ Supporting the networking protocols on both sides of the gateway — typically this will be Ethernet on the IP side and standard TDM networking protocols such as T1 or E1 on the PSTN side

✓ Maintaining “toll‐quality” voice calls by supporting fea-tures such as echo cancellation, silence suppression, and low latency (delay) during calls

�� Chapter 4: Getting the Most Out of Skype for Business 27


Making Enterprise Voice More Robust with Survivability

For enterprises with more than one location — pretty much every medium and large enterprise — it’s common to use a centralized site to manage call control and PSTN connectivity services.

While this approach increases efficiency and reduces costs, it also exposes vulnerabilities in the network because key devices such as the front‐ and back‐end servers and media-tion servers all reside in the same location (usually the main office). As a result, enterprise voice services are vulnerable:

✓ If there’s a disruption in service to the enterprise wide area network (WAN) connection between the branch and central site, the branch site will lose all communications connectivity both within and outside of the enterprise.

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

In both cases, you can see that it’s imperative to design 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 certified Skype for Business Enterprise Voice network gear that can pick up some of the processing and connectivity slack when problems occur. In order to pre-vent outages from disrupting enterprise voice services, you need to plan for network resiliency and survivability in three key areas:

✓ Central sites: This area involves building sufficient redundancy into the network. For example, an Enter-prise Voice deployment can be made more redundant and resilient by installing backup server pools in other locations 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 fail-ure situation. (Read the section “Understanding SBAs” for more information.)

✓ All sites: The installation of an SBC provides additional security and intelligent routing of calls regardless of the network’s status.

Understanding SBAsIt’s the role of the SBA — and its larger cousin, the Survivable Branch Server (SBS) — to provide resiliency and survivability (hey, it’s right in the name!) for Skype for Business Enterprise Voice branch sites. When a branch’s communications are pro-vided through Skype for Business Server 2015 in the central site, the loss of WAN connectivity can leave branch offices without internal (for example, desk to desk) or external com-munications capabilities.

Deploying an SBA at each branch office makes 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 does this by acting as a local PSTN gateway and providing basic voice telephony services to employees in the branch office. When the connectivity to the main office is restored, the branch office reverts back to the orig-inal 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 Enterprise Voice service works without a hitch during a cen-tral site or WAN outage. Instead, they mean that the most essential services stay on until the network is fully restored. By essential services, we’re referring to

✓ Inbound and outbound PSTN calls

✓ Internal enterprise calling — both within the site and between sites

✓ Basic IM capabilities

✓ Dial‐in (PSTN) conferencing

✓ Voicemail

�� Chapter 4: Getting the Most Out of Skype for Business 29


Other services — such as E911, web conferencing, videocon-ferencing, and other advanced Skype for Business features — may not be available until the network is fully restored. But, with an SBA, enterprise employees can keep communicating and working right through the outage — which, for many busi-nesses, is downright essential.

The SBA is designed for smaller (but not necessarily small!) branches. For deploying an SBA/SBS in branch offices, Microsoft recommends the following guidelines:

✓ Branch sites between 25 and 1,000 users should deploy 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 a dedicated Skype for Business Enterprise Voice 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 the Internet Telephony Service Provider (ITSP) via a SIP trunk connection

This connectivity allows users within the branch site environ-ment to bypass the usual SIP connection to the central site and to instead route calls through a different communications channel, while the SBA or SBS takes over the call‐handling duties usually performed in the central site.

In Chapter 5, we introduce SBCs. Some SBCs may include SBA functionality and Skype for Business certification. In this case, a single device could handle three key functions:

✓ 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.


Chapter 5

Improving Enterprise Voice Quality, Security, and

Reliability with an SBCIn This Chapter

▶ Introducing the SBC

▶ 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) plays an important role in an Enterprise Voice deployment and provides

a host of security, service enablement, and control func-tions. Enterprises need them and so do service providers. And Microsoft recommends them for Skype for Business Enterprise Voice deployments to ensure interoperability and functionality.

In this chapter, we introduce the SBC and discuss how it enhances the SIP trunking connection, integrates with IP PBXs, improves Quality of Service (QoS), and even enables emergency voice services. You also see how SBCs help differ-ent network elements — even those from different vendors — get along. Finally, we explain how SBCs can help simplify the control and troubleshooting of Enterprise Voice networks.



Introducing the SBCThe SBC is crucial in a Skype for Business Enterprise Voice deployment. It gets its name because of what it does (controls SIP sessions) and where it sits in the network (at the edge, or border, between your network and the outside world). An SBC provides all sorts of security and mediation services to keep things running smoothly.

An SBC communicates between two network end devices, such as a SIP VoIP call between two phones (an example of a SIP session). The SBC does this session controlling at the point where traffic is handed off from one network to another (the border), such as when a voice call leaves the enterprise and goes onto a service provider’s SIP trunks. Because of where the SBC fits in the network, it can be usefully implemented by both service providers and the enterprises they serve.

Why do networks need an SBC? To counter IP‐based network attacks, for one thing (remember: VoIP networks are still essentially IP networks and are subject to the same kinds of attacks as other IP‐based data networks). Also, VoIP networks are composed of different elements that require significant interworking and mediation to work properly.

Some of the main roles of an SBC in a network include

✓ Protecting the network from attacks and fraud:

• Denial of Service (DoS) attacks where bad guys attempt to overwhelm the network by bombarding it with thousands of fake login attempts (or VoIP calls)

• Spoofing attacks where nefarious users attempt to gain access to the network deceptively using false IDs

• Toll fraud attacks from hackers who can make thousands of long‐distance calls over your network at your expense

✓ Enabling SIP trunking, which allows enterprises to save money and operate more efficiently by connecting directly to an ITSP via SIP trunks

✓ Supporting better communications in varied network environments

��Chapter 5: Improving Enterprise Voice with an SBC 33


An SBC can help in a deployment where existing IP PBXs and other legacy telephony elements are integrated with the Enterprise Voice deployment. In this case, the SBC can smoothly translate between varying network protocols, codecs (encoders/decoders for digitizing media), bandwidths, and more.

Connecting to SIP Trunking Services

While some enterprises may use TDM voice services with their Enterprise Voice deployment, a growing number of enterprises are taking the VoIP revolution to its logical conclusion and partnering with SIP trunking Internet Service Providers (ISPs). 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. 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 performs several essential roles in a SIP trunking deployment:

✓ A gatekeeper role: The SBC looks at each SIP packet crossing between the Enterprise Voice network and the external ISP network, determining which packets 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. An SBC can perform the following translations:

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

• Transrating: SBCs can modify the bit rate of voice calls, video, and other SIP sessions crossing the network to accommodate different devices and dif-ferent 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 perform real‐time transla-tion of the codecs (encoding and decoding proto-cols) used for digitizing and transmitting calls, a process known as media transcoding. This can be essential when the endpoint devices involved in a call support different codecs.

• Comfort noise generation: Believe it or not, some of your users may think that there are problems with a call because it’s too quiet! If you have users who expect to hear a bit of white noise on the call, the SBC can add comfort noise to the call to let them know that the call is working as they expect.

• Network security: The SBC controls the admission of calls in and out of the enterprise and protects the network against Denial of Service attacks, toll fraud, and other attacks against the Enterprise Voice net-work. Additionally, the SBC can “hide” the topology of the Skype for Business Enterprise Voice network within the enterprise, so external parties aren’t able to detect the devices or servers within.

Integrating with Existing IP PBX Platforms

Many enterprises migrating to Skype for Business have an existing base of IP PBXs already in place that perform the same sort of call capabilities provided by Skype for Business



Enterprise Voice. In these cases, most enterprises won’t choose to perform a “rip and replace” of their existing infra-structure in favor of a Skype for Business Enterprise Voice infrastructure. Instead, many choose to gradually implement Enterprise Voice while retaining some or all of their existing IP PBX infrastructure. In some cases, this will be done in order to leverage the TDM telephony interfaces offered by the IP PBX. In other cases, the IP PBX stays in service to provide specific services or to serve some segments of the network while others are transitioned to Skype for Business Enterprise Voice.

The SBC plays a vital intermediation role and can provide SIP normalization, transcoding, and transrating to allow a smooth integration between Skype for Business Enterprise Voice and the IP PBX. Additionally, dial-plan routing can get really complex as users are moved from existing IP PBXs to Skype for Business Enterprise Voice. Instead of having to manually update dial plans in every IP PBX, a centralized SBC can look into the Microsoft Active Directory and, if the user is a Skype for Business Enterprise Voice user, route calls to the appropriate server or otherwise route it to the legacy IP PBX. This makes for a smooth migration without having to deal with the complexity of a workgroup‐by‐workgroup migration to Skype for Business Enterprise Voice.

Most large enterprises have a disparate IP PBX base — that is, 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 transcoding requirements.

In addition to its SIP normalization, transcoding, and transrat-ing functions, SBCs can also provide centralized call routing intelligence in the voice network, located logically “above” both the IP PBXs and the Skype for Business Enterprise Voice servers. In this way, the SBC can serve as the “brains” of the Enterprise Voice network, helping to ensure that calls are routed correctly through the most efficient use of network resources.



Ensuring Quality of ServiceQuality of Service (QoS) is important in all communications — voice, video, or data — but it’s particularly important for voice communications, where any degradation of sound quality, 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 Skype for Business Enterprise Voice, the SBC monitors, controls, and actively improves call quality through

✓ Call Admission Control (CAC): 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/Transrating: The SBC uses more efficient codecs when the network’s bandwidth is near capacity.

✓ VoIP prioritization: The SBC places voice calls higher in the pecking order (over, say, video or web conferencing) as network capacity is reached.

✓ Media Bypass: Skype for Business supports a process known as Media Bypass in which the Skype for Business Enterprise Voice Mediation Server can be bypassed. This 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 CAC and other functions.

Supporting E911E911 stands for Enhanced 911, and having it can literally mean the difference between life and death. E911 is an emergency service that adds location information to calls so emergency responders can automatically pinpoint the location of those calling for services.

Skype for Business supports E911, but it can’t do everything alone. In certain scenarios, you also need an SBC to facilitate the E911 functionality:



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

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

• In some cases, the ISP may not carry the location components of the SIP signal, in which case a TDM line can be connected to the SBC, enabling E911 to operate 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 to the Skype for Business Enterprise Voice Media-tion Server from the 911 service provider — something not all enterprises wish to do for secu-rity reasons — requiring an SBC to serve as a proxy between the 911 network and the Skype for Business network, passing all necessary location data while maintaining network separation and security.

Dealing with Interoperability between Vendors

SBCs are really good at playing the role of intermediary between Skype for Business Server 2015 and a SIP trunk-ing provider. The SBC’s capability to normalize SIP (that is, smooth out the differences in SIP variants) and to both trans-code and transrate media makes it a great go‐between in any sort of VoIP network deployment.

SIP equipment vendors — whether they’re making IP Gateways, SIP VoIP client devices, or whatever — 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 more 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.



It’s safe to say that the vast majority of Skype for Business Enterprise Voice implementations will involve equipment from more than a single vendor. This is especially likely in larger enterprises or enterprises that are transitioning their existing deployments to Skype for Business.

Chances are good that there are some subtle but impactful incompatibilities and differences in the way these differ-ent devices use SIP. The impact may be seen in missed or dropped calls or just a plain “the network is not working” type of scenario. Putting the SBC between these different network elements and letting it do what it does best (mediating) will solve the problem.

Centralizing Control and Troubleshooting

Because SBCs sit in a unique place in the Enterprise Voice network — at the edge of the network where voice and other UC traffic transitions between locations and between network borders — they can also play a unique role as a central con-trol point in the network.

The 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 service provider deter-mine and enforce centrally established rules about call per-missions 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

In This Chapter ▶ Supporting a wide range of compatibility and interoperability

▶ Providing resiliency and protection from attacks

▶ Getting centralized management

N ot all Session Border Controllers (SBCs) are created equal. The choice you make determines the level of secu-

rity, quality, control, and the types of services (for example, SIP trunking, E911) that your Skype for Business Enterprise Voice implementation will have. Sonus is a leading seller of SBCs and VoIP equipment. In fact, banks, retailers, airlines, and both global and regional communications service providers trust Sonus SBCs to deliver first-rate price/performance and market‐leading innovation in their networks. In this chapter, you dis-cover the ten reasons to choose Sonus SBCs when deploying Skype for Business Enterprise Voice.

Microsoft Compatibility and Qualification

As a qualified Skype for Business partner and a company that has secured real‐time communications since 1997, Sonus offers more Microsoft‐qualified SBCs than any other vendor in the marketplace today, from virtual SBCs that start at dozens of SIP sessions to world‐class appliances that support up to 150,000 concurrent SIP sessions. With Sonus, you can trust that your voice network will be compatible with Skype for Business.



Multivendor InteroperabilitySonus SBCs provide smooth interoperability with a vast range of legacy PBXs, IP PBXs, gateways, and much more. Whether you’re transitioning from a legacy PBX solution or simply upgrading from the latest version of Lync, Sonus has you covered.

Maximum 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 provide high availability, enabling calls to be com-pleted even under the most adverse conditions. To provide maximum resiliency, Sonus SBCs can be deployed in pairs (in what’s called Active‐Active mode) for load balancing and high‐availability requirements. They also balance the call load across multiple Skype for Business Enterprise Voice Mediation Servers to keep the network up no matter what.

When a network is compromised by a Denial of Service (DoS) attack, it can be crippled by a flood of SIP requests. Sonus SBCs offer sophisticated, real‐time firewall capabilities and techniques so your network stays online and productive.

Encrypted CommunicationsEncryption keeps prying eyes (and ears) from eavesdrop-ping on your business conversations and communications. The SIP standard uses only plain text signaling, which can be intercepted and understood by nefarious parties along the Internet highway. Sonus SBCs deliver 128‐bit AES encryption, so potential eavesdroppers can’t make heads or tails of your conversations. Additionally, the unique SBC architecture from Sonus performs real‐time encryption on a dedicated processor, so higher security never comes at the cost of lower performance.

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Rapid RecoveryShould a network outage occur, Sonus SBCs are designed to minimize the impact, so what you experience is a hiccup rather than a meltdown. For example, Sonus SBCs typically include redundant power supplies; in the rare event of a power failure, the SBCs seamlessly switch over to the backup power supply. And if something external to the SBC causes the outage (like an outage of the enterprise WAN connection), Sonus SBCs still keep running through built‐in survivability.

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 automati-cally looks for alternate routes to complete calls — without end‐users being any the wiser to the 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, which gives the user uninterrupted service.

Survivability for Branch SitesSonus SBCs include full support for Skype for Business Enterprise Voice Survivable Branch Appliances (SBAs) and 3G/4G failover capability. With Sonus SBCs, branch sites get high‐quality voice services, ready‐to‐go survivability, and require one less device in the network, which makes the net-work simpler to manage and less costly to operate.

Virtually Ready for the CloudSonus SBCs are now available as a software‐only product for virtualized environments. The Sonus SBC SWe (Software edi-tion) is built for architectures that support Network Functions Virtualization (NFV) and allows service providers and enter-prises to deploy an SBC on standard, commercial‐off‐the‐shelf (COTS) hardware in a virtualized environment or in their pri-vate Cloud. The Sonus SBC SWe also supports a wide range of hypervisors, including VMware, KVM (Linux), and Microsoft Hyper‐V, as well as Cloud infrastructures such as Amazon Web Services (AWS) and Microsoft Azure.



Centralized Policy ManagementSonus SBCs can be centrally managed, so whether you’re deploying 2 SBCs or 20, policy configuration and provisioning never grows in complexity, giving you lower expenses for IT and better/faster results for users. Centralized SBC manage-ment 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

Voice calls frequently use multiple codecs, requiring media transcoding. The Sonus SBC platform features a separate pro-cessing architecture for media transcoding and transrating, so the overall performance of the SBC doesn’t take a “hit” when processor‐intensive transcoding is taking place. Whatever the transcoding load, the encryption/security and the routing modules are unaffected.

An independent third‐party test showed that the enterprise/branch office SBC from Sonus had twice the concurrent call capacity of the nearest competitor for transcoded sessions. This functionally separated architecture also makes it easier and less expensive to add more processing power for a spe-cific function without the need to upgrade other parts of the SBC as well.

Wide‐Ranging Media SupportSonus builds its own digital signal processing (DSP) firmware instead of relying 100 percent on third‐party technology. As a result, it has the freedom and the capabilities to add new media processing features as needed on its customer’s timetable — not on someone else’s timetable.


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