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WHITE PAPERAn Introduction to the Basics of Video Conferencing

WHITE PAPER An Introduction to the Basics of Video ConferencingIntroductionIn the next few years we shall see explosive growth in the useof video conferencing as a fundamental tool for businessesto enhance communication and collaboration betweenemployees, partners and customers. The technology hasdeveloped considerably from early adopters to its currentform of mass market roll-out. It’s anticipated that nearlyhalf of information workers will have some type of personalvideo solution in 2016, up from just 15% today 1. With videoconferencing becoming a core component of IT infrastructurethat enables communication and collaboration, businesses willbe looking to providers of telephony, business applications andnetwork infrastructure services to include this capability as partof their offering.This report will examine the basic components of thetechnology, considerations for deploying video conferencingsolutions, and will introduce the Polycom RealPresence Platform to readers.What is video conferencing and how does it work?To set the foundations for future elaboration, at the simplestlevel, a video conference is an online meeting (or a meetingover distance) that takes place between two parties, whereeach participant can see an image of the other, and whereboth parties are able to speak and listen to the otherparticipants in real time. The components necessary tomake this happen include: A microphone, webcam and speakers A display A software program that captures the voice stream from themicrophone, encodes it, transmits to the other participant,and simultaneously decodes the digital voice stream beingreceived from the remote participant in the video conference(most commonly referred to as a “Codec”). A software program that bridges both parties togetheracross a digital connection, managing the exchange ofvoice and video between participants. At either end of theconnection, the video and voice traffic is combined anddelivered to each participant in the form of a real-time videoimage and audio stream. An optional management tool for the scheduling of videoconferencing sessionsAt a slightly more advanced level, it is also possible to providethe ability to share content from a device during a video call.The quality and type of content that can be shared depends onthe rate of data exchange during the call.Terminology used by video conferencing users to describe theprocess of dialling into and participating in a virtual meeting isknown as “joining a bridge.” Different virtual meeting rooms areassigned unique “bridge numbers,” and users join a video callby “dialling a bridge number.”Point-to-point video conferencingVideo-enabled meetings happen in two distinct ways: eitherpoint-to-point or with multi-point. In point-to-point, the simplestscenario is where one person or group is connected to another.The physical components (i.e. microphone and camera) thatenable the meeting to take place are often integrated in todesktop computing solutions like a laptop or tablet, or can becombined into dedicated, room-based hardware solutions.An example of point-to-point video conferencing.1. Forrester—Preparing for Uneven Corporate Adoption of Video Communications, May 9, 20112

WHITE PAPER An Introduction to the Basics of Video ConferencingA use-case scenario of multi-point video conferencing.Where desktop solutions tend to be used by individuals,room-based solutions utilize dedicated video conferencingtechnology where groups of people can be seen, heard andcan naturally participate in the meeting.Multi-point video conferencingIn multi-point video calls, three or more locations areconnected together, where all participants can see and heareach other, as well as see any content being shared duringthe meeting.In this scenario, digital information streams of voice, videoand content are processed by a central, independent softwareprogram. Combining the individual participant’s video andvoice traffic, the program re-sends a collective data streamback to meeting participants in the form of real-time audioand video imagery.Individuals can participate in a meeting in an “audio only”mode, or combine audio with video images of the meetingon screen. Depending upon the technical capability ofthe video conferencing system being used, images seenby participants are either classified as “active speaker” or“continuous presence.”In “active speaker” mode, the screen only provides an imageof the person that is speaking at any point in time. In moreadvanced solutions with “continuous presence” mode, thebridge divides the image on the screen into a number ofdifferent areas. The person speaking at any point in time ispresented in a large central area, and other meetingparticipants are shown displayed around the central image.The “continuous presence” mode thus allows meetingparticipants to view and interact with all meeting participantsin a ‘virtual meeting room.’The software program which creates the “virtual meeting room”and the digital processing hardware on which it resides, is oftencalled a video bridge, or “bridge”, for short. Another term for abridge which is often used is a video conferencing “multi-pointcontrol unit” or “MCU.”Whereas point-to-point video conferencing is relatively simple,the creation and management of multi-point video conferencescan be complex. An MCU must be able to create, controland facilitate multiple simultaneous live video conferencingmeetings. A further complexity is added when differentlocations may connect to the meeting over digital or analoguestreams at different speeds, with different data transport andsignalling protocols employed to facilitate the communication.To link these users into a common, virtual meeting, the MCUmust therefore be able to understand and translate betweenseveral different protocols (i.e. H.264 for communication overIP, and H.263 for ISDN). The MCU will also allow those joiningthe video bridge to do so at the highest speed and the bestpossible quality that their individual system can support.Although there are two separate processes taking place here,this is often jointly referred to as “transcoding.”It is important to note that not all bridges provide suchtranscoding capability, and failure to do this can seriouslyimpact the quality and experience of video calls. Whentranscoding is not provided and users dial into a bridge3

WHITE PAPER An Introduction to the Basics of Video Conferencingover a range of different connection speeds, it is possible thatthe bridge may only be able to support the video meetingby establishing the connections at the lowest commondenominator. To illustrate the negative effect of this, considera meeting that takes place with most users joining the bridgefrom the high-speed corporate network, but where one or twoindividuals dial into the meeting from home on low-bandwidthDSL or ISDN. In this case the experience of the many corporateusers is downgraded to the lowest common denominator ofthe home-users, potentially making the video call ineffective.Where effective transcoding is supported by the MCU, thoseon the corporate network will continue to enjoy HD videoquality, while remote users receive quality commensurate withtheir connection speeds.In summary, when an MCU is designed well, integrating easilywith multiple vendors and allowing users to call in at the datarate and resolution they want or need to—the result is an easy,seamless experience for all users, allowing people to focus onthe meeting, not the technology.The language of video conferencingAs video conferencing technology has evolved, two mainprotocols have emerged to provide the signalling controlfor the establishment, control and termination of videoconferencing calls: SIP (Session Initiation Protocol) and H.323.For the encoding and decoding of visual information, theindustry is moving towards the industry standard known asH.264, which was developed to provide high-quality video atlower bandwidth over a wide range of networks and systems.An extension to the H.264 protocol is Scalable Video Coding(SVC), which is established to facilitate the enablement of videoconferencing on a wider range of devices, such as tablets andmobile phones.Bridging architecture and functionalityAs described above, the combination of software and thehardware that creates the virtual meeting rooms is calleda “video bridge.” Virtual meeting rooms are identified bytheir “bridge numbers.” With multiple calls taking placesimultaneously, software analyses all the different datastreams coming into the bridge processors, and assignsdata streams accordingly.At the simplest level, the processing workload for bridges isdependent upon four factors: The number of locations that dial into each bridge The number of conferencing calls that each bridge musthandle simultaneously4 The amount of data that is being received on each digitalstream: higher resolutions of images and sound (i.e. HighDefinition) generate more data that needs to be processed The degree of transcoding that the bridge must performwhile handling calls being received at different connectionspeeds and utilizing different protocolsAs the workload increases, each bridge must process moredata. Performance can therefore be improved by increasingthe number of Digital Signalling Processors (DSPs) utilized todecode and encode the digital streams entering and leavingMCUs. If the bridging function becomes overloaded, videoand voice information may be lost, causing latency to beintroduced into calls, both of which can degrade the videomeeting experience.Extra processing resource can be provided for the bridgingfunction by either utilizing a more powerful bridge (witha greater number of DSPs) or through a virtual softwareapproach, where the software that controls the signallingfunction can operate independently of the physical hardware.A conference call with an assigned conference number doesnot have to take place, or be processed by a dedicated pieceof hardware. The call can be “virtualized”, and assigned towhatever physical bridge has the correct resource or capacityto handle the call. A virtualization manager oversees whichphysical bridge has the capacity, and assigns incomingcalls accordingly.In extreme, but rare circumstances, the virtualization managermay assign resources for a call across several differentphysical bridges that work in tandem together. Known as“auto-cascading”, the resources within the physical bridge canbe instructed by the software to operate in a “parent-child”arrangement, with one bridge “owning” the conference call,and the others sharing the workload.In the continuous presence mode of presentation, the bridgewill automatically provide the screen templates in which theviewers will see the other meeting participants. The bridgecan also provide some administrative functionality for thecall, such as assigning passwords to enter each meeting, andproviding Interactive Voice Response (IVR) functionality, wherecall participants can be greeted and instructed by customizedvoice greetings.Although most participants will actively dial into a videoconferencing meeting, the bridge can be programmedto automatically dial out to participating locations andautomatically connect them in to a meeting. For example,the bridge could automatically wake up the cameras in

WHITE PAPER An Introduction to the Basics of Video Conferencingremote meeting rooms, and link those meeting rooms into aprescheduled call. Participants of such a meeting would simplyhave to walk into the video room at the correct time, and jointhe meeting.Video call management and protocol conversionIn order to build an architecture that scales, the softwareplatform must be able to provide call signalling functionality,and dynamically manage the set-up and maintenance of a largenumber of video calls. The software architecture has to becapable of reconfiguring itself and its resources in real-time, sothat these resources are used to their best ability. In addition,the software architecture has to understand the bandwidthrequirements of each call being placed, the policy that isassociated with each call (the prioritization and importance ofa call), and where the participants of a call are geographicallylocated. By understanding this, the software platform can utilizelocal resources instead of redirecting data streams and callsignalling to resources that are far away, an approach whichwould eat up large amounts of bandwidth on WAN links thatare very costly.The software platform should also be able to instantly detectany failure of hardware resources or loss of communicationacross infrastructure links, so that it can re-direct traffic andre-establish calls utilizing alternative resources, without overlyimpacting video calls or their quality.When systems on different customer premises try to join thesame video call using devices which run different protocols(i.e. H.323, RTV or SIP), the video conferencing platform mustfirst perform protocol conversion to a common language sothe infrastructure can understand and process informationcorrectly. In other words, the software platform should provideintrinsic gateway functionality between devices that talkdifferent languages.The Polycom RealPresence DMA sits in front of the bridges,and interfaces between the outside world and the bridgingresources. This optimizes how incoming video calls arehandled by virtual resources at its disposal. The PolycomRealPresence DMA can apply business rules that help it placeincoming meetings on bridges that make the most sense, eitherfor capacity, geography, or other priority rules.Let us consider three examples of this approach and see how it simplifies the process.Example ACustomer A in California wants to meet with Customer B in New York, Customer C in London andCustomer D in Paris. The Customer has a video bridge in Denver and a video bridge in Paris anda virtualization manager on a server in London. In this situation, the virtualization managementsoftware would identify that two participants wanted to join the call from the U.S., and may, forexample purposes, direct them to the resources on the Denver bridge. Likewise, the Europeanparticipants may be directed to the Paris bridge, with overall control of the call being given to theMaster Denver bridge. Under this scheme, large amounts of video data are not shipped across atransatlantic WAN, thereby potentially providing cost savings.Example BIn the above example, the U.S. customers are using an H.264 based system, and in Europe theyare using Microsoft Lync enabled video conferencing based upon RTV. In this scenario, thevirtualization management software on the London server acts as a gateway between Microsoft and the U.S. video resources, converts the Microsoft signalling, and establishes the whole callusing the bridges in the U.S. and Paris.Example CIn this example, the call is proceeding but the bridge in Denver suddenly stops functioning dueto a fire in the data centre. The Virtualization Manager in London detects this, and redirects thevideo traffic across the WAN link to the Paris bridge. Users connecting via H.323 simply redialto re-join the call, with the administration and management being performed seamlessly in thebackground. However, for SIP based calls there is an added advantage: the platform will detectthe problem and reconnect the participants back into the call automatically, hopefully before theuser has even noticed that there was a problem.5

WHITE PAPER An Introduction to the Basics of Video ConferencingDevice managementContent managementTo enable large-scale deployment and management ofvideo conferencing solutions, the software platformprovides for the management and maintenance ofhardware infrastructure components through a separatefunctional area: The Device Manager.Historically, the primary motivating factor for most companieshas been to use video conferencing as a way of savingbusiness travel costs. Recently, organizations are beginning tounderstand that the benefits of video conferencing can impactmany different parts of an organization including; training,marketing, education, compliance, internal communications,advertising, PR, to name just a few.The Device Manager can help dynamically provision devicesand components of the video conferencing infrastructure.Once component hardware is deployed within the networkand its infrastructure, the Device Manager will monitor andhelp troubleshoot problems with these devices. Whensoftware updates are required, the Device Manager willhelp deploy them.As the usage of video conferencing in these fields has begunto grow, customers have discovered the potential to not onlyuse video conferencing to communicate in real-time, butalso to uncover the possibilities that exist for re-using digitalrecordings of past events and communications.A significant contributing factor to the rise in demand for videoconferencing is because of the ease of use by which calls canbe established by users. The scheduling and management ofcalls has become easy, through the creation of user-friendlyscheduling portals, or via integration into Microsoft Outlook .Moving beyond “meetings,” the same technology is beingused to create digitally encapsulated rich media, which canthen be edited, enhanced, archived, and broadcast acrossmultiple media. These assets can be made available to targetaudiences on-demand.The Device Manager will also provide reporting, andcomprehensive details of video calls, processing theinformation to evaluate current system usage, andexpansion plans for the video network.For example:Security Video-on-demand—The software platform automates thecreation of archived versions of any live event webcast sothat customers can replay them on demand, as desired.Many organizations who have invested in video conferencingwill inevitably need to be able to assist mobile or home workerswanting to dial into their company network, and participatein video calls with colleagues. The software platform musttherefore provide the capability to enable, and manage this.Likewise, video conferencing-enabled organizations will alsowant to use the technology to communicate with their partnersand customers. This will only be possible if video traffic is ableto securely traverse the firewalls from one customer to another.Firewall traversal is a particular challenge to video, as the datafirewalls try to re-organize data packets. The implementationof a video firewall such as the Polycom VBP (H323) caneliminate this issue.6 Live event multicasting—The software platform enables thestreaming of recorded webcasts, and supports both the pushand pull of video to the streaming servers. Media management—The software platform can be usedto control how video content will be aggregated, approved,categorised, edited and published. Storage and archiving—The software platform establishesrules for the lifecycle of storage for bandwidth-intensivevideo content: customers can determine how the content willbe retained, transcoded and stored in the Cloud, or acrosscorporate resources without daily, hands-on maintenance.

WHITE PAPER An Introduction to the Basics of Video ConferencingThe Polycom RealPresence PlatformUniversal access and securityIn the previous section, we explained the five basic functionalareas that constitute the software platform Polycom hasdeveloped to enable scalable, reliable, and cost-efficientvideo conferencing solutions. The Polycom RealPresenceplatform breaks down the core infrastructure for enabling videoconferencing into universal video collaboration, virtualizationmanagement, video resource management, universal accessand security and video content management.Video content managementUniversal video collaborationProviding the bridging capability at the core of videoconferencing, this provides the software for multipoint video,voice and content collaboration that connects the most peopleat highest quality and lowest cost.Virtualization managementProviding the call management and protocol conversion thatallows the bridging resources to be virtualized, this providesthe software that enables multi-tenancy and massive scale,redundancy and resiliency.Video resource managementProviding the device and software management of endpointsand infrastructure, enabling central management, monitoringand the delivery of video collaboration across organizations.The software that easily and securely connects videoparticipants in and outside a customer firewall and optimizesfor a best collaboration experience.Software that enables organizations to support their businesscustomers for secure video capture, content management,administration and delivery.SummaryWith demand for video conferencing growing rapidly, solutionsneed to provide a robust, resilient, scalable, and manageableinfrastructure that delivers unparalleled quality of experience.The Polycom RealPresence Platform is the softwareinfrastructure that underlies Polycom’s video conferencing,and binds it together by integrating with core networking andsecurity infrastructure. This enables secure collaboration forany number of users across heterogeneous networks, withup to 50% less bandwidth consumption than other competitorsolutions. By delivering an architecture based upon openstandards, Polycom has created a flexible, state-of-the-artvideo conferencing platform that provides superior investmentprotection, at the lowest total cost of ownership.7

WHITE PAPER An Introduction to the Basics of Video ConferencingAbout PolycomPolycom is the global leader in open standards-based unified communications and collaboration (UC&C) solutions for voiceand video collaboration, trusted by more than 415,000 customers around the world. Polycom solutions are powered by thePolycom RealPresence Platform, comprehensive software infrastructure and rich APIs that interoperate with the broadest setof communication, business, mobile and cloud applications and devices to deliver secure face-to-face video collaboration inany environment.Polycom, Inc.1.800.POLYCOMwww.polycom.comPolycom Asia Pacific Pte Ltd 65 6389 9200www.polycom.asiaPolycom EMEA 44 (0)1753 723282www.polycom.co.uk 2013 Polycom, Inc. All rights reserved. All Polycom names and marks associated with Polycom products are trademarks or service marks of Polycom, Inc. and are registered or common lawmarks in the United States and other countries. All other trademarks are property of their respective owners. No portion hereof may be reproduced or transmitted in any form or by any means, forany purpose other than the recipient’s personal use, without the express written permission of Polycom.7624 0713

called a video bridge, or “bridge”, for short. Another term for a bridge which is often used is a video conferencing “multi-point control unit” or “MCU.” Whereas point-to-point video conferencing is relatively simple, the creation and management of multi-point video conferenc