Office Communications Server 2007 Videoconferencing Interoperability

Transcription

1 Office Communications Server 2007 Videoconferencing Interoperability Microsoft Corporation Published: July 31, 2008 Executive Summary Microsoft Office Communications Server 2007 is the first Microsoft product to combine enterprise-ready IM (instant messaging), presence, videoconferencing, Web conferencing, and VoIP (Voice over IP) telephony in one solution. In addition, Office Communications Server 2007 includes real-time videoconferencing solutions running on servers in your intranet or interoperating with videoconferencing hardware vendors (such as TANDBERG or Polycom). Providing interoperability between Office Communications Server 2007 and videoconferencing vendors allows you to take advantage of your existing videoconferencing hardware investment while extending videoconferencing features to other users with minimal hardware investment and user training. The users that attend conferences using dedicated videoconferencing hardware can schedule meetings and determine attendee availability using familiar tools, such as Microsoft Office Outlook or Microsoft Office Communicator This paper discusses: An overview of videoconferencing, including benefits, features, and industry standards used in videoconferencing solutions. Features and capabilities of Office Communications Server 2007 that are utilized in videoconferencing solutions. Interoperability of Office Communications Server 2007 with existing videoconferencing vendor solutions. How Microsoft envisions future interoperability with videoconferencing vendors.

2 This is a preliminary document and may be changed substantially prior to final commercial release of the software described herein. The information contained in this document represents the current view of Microsoft Corporation on the issues discussed as of the date of publication. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information presented after the date of publication. This White Paper is for informational purposes only. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS DOCUMENT. Complying with all applicable copyright laws is the responsibility of the user. Without limiting the rights under copyright, no part of this document may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), or for any purpose, without the express written permission of Microsoft Corporation. Microsoft may have patents, patent applications, trademarks, copyrights, or other intellectual property rights covering subject matter in this document. Except as expressly provided in any written license agreement from Microsoft, the furnishing of this document does not give you any license to these patents, trademarks, copyrights, or other intellectual property. Unless otherwise noted, the companies, organizations, products, domain names, addresses, logos, people, places, and events depicted in examples herein are fictitious. No association with any real company, organization, product, domain name, address, logo, person, place, or event is intended or should be inferred Microsoft Corporation. All rights reserved. Microsoft, Active Directory, Outlook, PowerPoint, RoundTable, SharePoint, and Windows are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries. All other trademarks are property of their respective owners.

3 Contents Introduction... 4 Using This White Paper... 4 Videoconferencing Concepts... 4 Overview of Office Communications Server Videoconferencing Architecture in Office Communications Server Office Communications Server 2007 Concepts and Features Videoconferencing Audio Conferencing Interoperability with Partners Office Communications Server 2007 Interoperability with Videoconferencing Vendor Solutions Office Communications Server 2007 Interoperability with TANDBERG Solutions Overview of TANDBERG-based Solutions Interoperability with Office Communications Server Office Communications Server 2007 Interoperability with Polycom Solutions Overview of Polycom-based Solutions Interoperability with Office Communications Server How Microsoft Envisions the Future of Videoconferencing Interoperability Conclusion For More Information... 27

4 Introduction Microsoft Office Communications Server 2007 provides solutions for real-time communications within your organization, between federated networks, and with users on the Internet. The solutions include instant messaging, real-time audio communications, real-time videoconferencing, Web conferencing, and playback of recorded video conferences. Using This White Paper This white paper focuses on the interoperability of Office Communications Server 2007 with real-time videoconferencing vendors. This paper discusses the following topics: Creating videoconferencing solutions using Office Communications Server Creating videoconferencing solutions that interoperate Office Communications Server 2007 and videoconferencing hardware vendors. How Microsoft envisions future interoperability with videoconferencing vendors. As you read this white paper, identify the videoconferencing features that are needed in your organization and select the videoconferencing solutions that best address your organization s needs. Videoconferencing Concepts Videoconferencing is part of a $4-5 billion dollar real-time collaboration technology sector that includes audio, video, and Web conferencing products and services. More and more organizations adopt these products and services each year. Some of these components are not only installed within an organization, but are also available on a pay-as-you-go basis by conferencing service providers. Although the implementation for each videoconferencing hardware and software vendor may differ, the following are some of the common components found in most videoconferencing solutions: Group videoconferencing endpoints. These devices are videoconferencing clients that are designed to be used in shared environments such as meeting rooms, boardrooms, and auditoriums. These devices are sometimes referred to as room videoconferencing endpoints or systems. Individual videoconferencing endpoints. These devices are videoconferencing clients that are designed to be used for personal or single-person use. Examples of this type of device include videophones, executive systems, and PC-based solutions optimized for the office and cubicle work environment. Multipoint control units (MCUs). These devices enable two or more participants to be in a single videoconference. These devices are also known as bridges. Videoconferencing gateways. These devices connect users on different networks, typically IP and Integrated Services Digital Network (ISDN) as well as public switched telephone networks (PSTNs) NAT-firewall traversal. This technology enables audio and video calls to connect across different networks and user domains. You can use them to connect your videoconferencing infrastructure with federated networks or users who access your infrastructure from the Internet. A federated network is a network that is owned and managed by two organizations for the purpose of sharing networking resources and information. Gatekeepers. The H.323 gatekeeper provides call control, bandwidth management, and address translation services. The videoconferencing endpoints register with the gatekeeper and provide their IP address and H.323 alias (also known as an E.164 alias). The gatekeeper manages these addresses and facilitates the communications Microsoft Office Communications Server

5 between endpoints as well as between endpoints and other infrastructure components (such as MCUs and gateways). The following figure illustrates the role of gatekeepers in establishing connections between videoconferencing endpoints. Figure 1. Role of gatekeepers in establishing a videoconferencing session between endpoints Microsoft Office Communications Server

6 Interoperability in modern videoconferencing solutions is facilitated by industry standards and protocols, including: H.323. This is an umbrella standard that defines the protocols used to provide audiovisual communications sessions. This standard is widely implemented by voice and videoconferencing equipment manufacturers and deployed by service providers and enterprises for both voice and video services over IP-based networks. The following figure illustrates the other standards and protocols that are encompassed in the H.323 umbrella standard. For more information about the H.323 standard, see H.323: Packet-based multimedia communications systems at H.323/e. Figure 2. H.323 umbrella standard and the relationship with other standards and protocols H.239. Typically, videoconferences have an audio channel, a video channel, and optionally a data channel. The video channel usually shows the participants. The H.239 standard defines how to establish additional video channels, which can be used for additional video sources such as a computer display or an additional camera. The H.239 standard does this by labeling video channels with a role and then the role labels are used by H.320 and H.323 based systems. In multipoint conferencing, the H.239 standard defines token procedures to guarantee that only one endpoint in the conference sends the additional video channel, which is then distributed to all conference participants. For more information about the H.239 standard, see H.239: Role management and additional media channels for H.300- series terminals at H.264. This standard is a video compression codec, which is also known as MPEG-4 Part 10, MPEG-4 Advanced Video Coding (AVC), or the Joint Video Team (JVT) codec. The goal of the H.264 standard is to provide a standard means of sending high quality video at substantially lower data rate requirements. This standard is typically used for storing video on DVDs and broadcasting video over Real-time Transport Protocol (RTP) in IP-based networks. H.264 is widely used for providing high definition (HD) quality video in standards-based video conferencing systems. For more information about the H.264 standard, see H.264: Advanced video coding for generic audiovisual services at Microsoft Office Communications Server

7 Centralized Conferencing Control Protocol (C3P). A custom protocol for communicating conference creation and control commands from clients to Office Communications Server C3P commands are carried as XML in SIP SERVICE or INFO messages. C3P commands are carried over HTTPS to all conferencing servers. For more information about the C3P standard, see Centralized Conferencing Control Protocol at Session Initiation Protocol (SIP). The industry standard protocol described in IETF RFC 3261 that defines a standard for session setup, termination, and media negotiation between two parties. It is widely used for Voice-over-IP (VoIP) and video call signaling in IP networks. SIP is an alternative to H.323 for VoIP and video call signaling. Computer Supported Telecommunications Application (CSTA). This standard is an abstraction layer for telecommunication applications that is independent of the underlying signaling protocols and devices. The core of this standard is the definition of call control features, such as call answering, call forwarding, bridging calls, and call hold. For more information about CSTA, see Computer Supported Telecommunications Applications (CSTA) at Persistent Shared Object Model (PSOM). A proprietary protocol for the transport of real-time data, including audio and video. PSOM uses TCP or TLS as the underlying transport. Secure Real-time Transport Protocol (SRTP). An IETF standard protocol that is used in Office Communications Server 2007 to securely transport audio and video content to various media devices. It is based on the RTP that defines a packet format for carrying audio and video over IP networks. RTCP (Real-Time Control Protocol). An IETF standard protocol used in conjunction with RTP and SRTP to convey information about the signal quality of an audio/videoconferencing session to various media devices. The following figure illustrates the protocol interaction between Office Communications Server 2007 and client computers running Office Communicator Microsoft Office Communications Server

8 Figure 3. Protocol interaction between Office Communications Server 2007 and client computers running Office Communicator 2007 Overview of Office Communications Server 2007 Office Communications Server 2007 is the most recent version of real-time conferencing solutions developed by Microsoft. Office Communications Server 2007 complements existing collaboration and communications products such as Microsoft Exchange Server 2007 and Microsoft Office SharePoint Server Office Communications Server 2007 augments the collaboration features of these products by adding real-time instant messaging, voice conferencing, Web conferencing, and videoconferencing. Microsoft Office Communications Server

9 Videoconferencing Architecture in Office Communications Server 2007 The architecture of Office Communications Server 2007 allows for deployment in a number of different configurations, based on the business, scaling, and availability requirements of an organization. This document focuses on the Enterprise Edition: Consolidated Configuration scenario as described in the Office Communications Server 2007 Document: Technical Overview. For more information about this and other scenarios, see: Office Communications Server 2007 Document: Technical Overview at Office Communications Server 2007 Document: Planning Guide at C3B596F4&displaylang=en. The following figure illustrates a common deployment scenario for Office Communications Server 2007: the Enterprise Edition: Consolidated Configuration scenario. This scenario is typically used as the initial deployment for mission-critical large enterprise instant messaging and conference usage. This scenario assumes one centralized geographic location that provides videoconferencing solutions within that location. The solution includes four server computers running the Office Communications Server 2007 server roles. The Enterprise Edition: Consolidated Configuration scenario is a pool configuration in which all server components are collocated on the pool s front-end servers (with the exception of the back-end database, which must reside on a separate dedicated computer). Consolidated Configuration provides scalability and high availability and yet is easy to plan, deploy, and manage. For more information about this scenario, see the Enterprise Edition: Consolidated Configuration and Perimeter Network Configuration for IM and Conferencing sections in Office Communications Server 2007 Document: Technical Overview. The following technologies, services, and hardware components are required as prerequisites to deploy this solution: Active Directory running in Windows 2000 native mode or higher functional level in the domain in which the computers running Office Communications Server 2007 are members. Microsoft SQL Server 2004 with Service Pack 4, SQL Server 2005 Service Pack 1, or a later version of SQL Server Service Pack that provides database storage for the Enterprise Pool. Public key infrastructure (PKI) to provide certificates used in mutual server computer authentication and external client authentication. Hardware load balancer for the computers in the Enterprise Pool. Microsoft Office Communications Server

10 Figure 4. Enterprise Edition: Consolidated Configuration scenario that supports videoconferencing for internal and external users Microsoft Office Communications Server

11 The following table lists the core Office Communications Server 2007 components used in this scenario. Table 1. Office Communications Server 2007 components used in scenario Component Focus Focus Factory Web Conferencing Server A/V Conferencing Edge Server IM Conferencing Server Telephony Conferencing Server Conferencing Server Factory Description The Focus is the conference state server. It is implemented as a SIP user agent that is addressable by using a conference URI. The Focus runs in the User Services module of all front-end servers. All group IM, multiparty A/V, and data collaboration sessions are managed on the server by the Focus. The Focus Factory is the part of the Focus that is responsible for scheduling. When a user creates a new meeting, the meeting client sends a SIP SERVICE message to the Focus Factory, which creates a new instance of the conference in the conference database and returns information about the newly created conference to the client. A separate instance of the Focus exists for each active conference. Manages conference data collaboration, including native support for Microsoft Office PowerPoint presentations, Microsoft Office document sharing, white boarding, application sharing, polling, Q&A, compliance logging, annotations, meeting summaries, handouts, and various multimedia formats. The Web Conferencing Server can reside either on the front-end server (Standard Edition and Enterprise Edition Consolidated Pool) or on a separate physical computer (Enterprise Edition Expanded Pool).The Web Conferencing Server uses PSOM, a Microsoft Office Live Meeting protocol, for uploading slides to a meeting. Provides multiparty IP audio and video mixing and relaying, including Microsoft RoundTable, by using industry standard RTP and RTCP. The A/V Conferencing Edge Server can reside either on the front-end server (Standard Edition and Enterprise Edition Consolidated Pool) or on a separate physical computer (Enterprise Edition Expanded Pool). Enables group IM by relaying IM traffic among all participants. When a third participant is added to a peer-to-peer IM conversation, the initiating client invites the IM Conferencing Server to the conversation. From that point, all messages among the participants are routed through the IM Conferencing Server. The IM Conferencing Server is an integral part of the front-end server and cannot be installed on a separate computer. Responsible for ACP (audio conferencing provider) integration. Supports both dial-out and dial-in, as well as standard third-party call control features such as mute and eject. The Telephony Conferencing Server does not support mixing VoIP and PSTN in the same call. To connect dial-out to PSTN endpoints requires a Mediation Server, as described later in this overview. The Telephony Conferencing Server is an integral part of the front-end server and cannot be installed on a separate computer. When the Focus requests a particular conferencing server for a meeting, the Focus sends the request to the Conferencing Server Factory, which determines which conferencing server is available to service the request and returns its URL to the Focus. The Conferencing Server Factory is responsible for provisioning a meeting for a particular media type on a conferencing server by using local policies for creating meetings. A Conferencing Server Factory provisions meetings according to local policies and takes into account the current load on the conferencing servers before assigning one to a meeting. For information about front-end servers and components that run on them, see Other Server Components Required for Conferencing in Office Communications Server 2007 Document: Technical Overview. Microsoft Office Communications Server

12 The following table lists additional Office Communications Server 2007 components that support external users. Table 2. Additional Office Communications Server 2007 components that support external users Component Access Edge Server Director Web Conferencing Edge Server A/V Edge Server HTTP Reverse Proxy Description Formerly known as the Access Proxy, the Access Edge Server handles all SIP traffic across the corporate firewall. The Access Edge Server handles only the SIP traffic that is necessary to establish and validate connections. It does not handle data transfer, nor does it authenticate users. Authentication of inbound traffic is performed by the Director or the front-end server. The Access Edge Server is essential for all external user scenarios, including conferencing, remote user access, federation, and public IM connectivity. The Office Communications Server 2007 Director is the recommended internal next-hop server to which an Access Edge Server routes inbound SIP traffic destined to internal servers. The Director authenticates inbound requests and distributes them among the servers in the Enterprise pool or to the appropriate Standard Edition server. The Web Conferencing Edge Server proxies PSOM traffic between the Web Conferencing Server and external clients. External conference traffic must be authorized by the Web Conferencing Edge Server before it is forwarded to the Web Conferencing Server. The Web Conferencing Edge Server requires that external clients use TLS connections and obtain a conference session key. The A/V Edge Server provides a single trusted connection point through which inbound and outbound media traffic can securely traverse NATs and firewalls. The industry standard solution for multimedia traversal of firewalls is ICE (Interactive Connectivity Establishment), which is based on the STUN (Simple Traversal Underneath NAT) and TURN (Traversal Using Relay NAT) protocols. The A/V Edge Server is a STUN server. All users are authenticated to secure both access to the enterprise and use of the firewall traversal service that is provided by the A/V Edge Server. To send media inside the enterprise, an external user must be authenticated and must have an authenticated internal user agree to communicate with him or her through the A/V Edge Server. Office Communications Server 2007 conferencing support for external users also requires deploying an HTTP reverse proxy in the perimeter network for the purpose of carrying HTTP and HTTPS traffic for external users. The HTTP reverse proxy is used to download the following data for external users: Address Book Server files Web conferencing content Expanded distribution lists for group IM The reverse proxy does not run Office Communications Server 2007 or carry SIP traffic. Microsoft Office Communications Server

13 Office Communications Server 2007 Concepts and Features You can deploy Office Communications Server 2007 in organizations that support a small number of users or large organizations that have a large number of users. Office Communications Server 2007 is available in the following editions: Standard Edition. This edition provides all the features available in Office Communications Server 2007, but runs on a single computer. Standard Edition is typically selected for smaller organizations or in scenarios in which branch offices are isolated from one another. Enterprise Edition. This edition provides all the features available in Office Communications Server 2007, but can be run on multiple computers to scale to the desired number or users and to provide fault-tolerance. This edition is typically selected for larger organizations or in scenarios in which branch offices are interconnected with one another. This white paper focuses on deploying the Enterprise Edition. For more information about Office Communications Server 2007, see Communications Server 2007 Document: Technical Overview at For more information about how Exchange Server Unified Messaging integrates with Office Communications Server 2007, see Exchange Server 2007 Unified Messaging at Videoconferencing Office Communications Server 2007 supports multiparty audiovisual (A/V) conferencing. Users can specify audiovisual when scheduling a conference or can add audio or video to an existing IM conversation or conference call. Managing multiparty audio and video sessions is the job of the A/V Conferencing Server. The A/V Conferencing Server can be collocated with the pool front-end server or deployed in the pool on a separate computer for greater scalability. When deployed on a separate computer, the A/V Conferencing Server can support up to 250 participants within a single session and up to 1,250 total participants per A/V Conferencing Server. Office Communications Server 2007 also extends audiovisual conferencing to external users. The A/V Edge Server acts as a media relay for the transmission of both audio and video signals across corporate firewalls. This makes it possible to share audio and video with external users. The A/V Edge Server can be collocated with the Access Edge Server or installed on a separate computer in the perimeter network. Office Communicator clients support peer-to-peer audiovisual communication for users both inside and outside the organization s firewall. Office Communications Server 2007 supports the RoundTable communications system, which is an A/V conference-room device from Microsoft that provides a 360-degree surround video and audio experience. Attending a video conference that uses RoundTable is similar to attending a meeting in person. The audio and video of the entire conference room is delivered to other videoconferencing attendees in real time. Audio Conferencing External audio conference participants who have not deployed Office Communications Server can participate through the services of a third-party Audio Conferencing Provider (ACP). The provider enables conferencing over an external PSTN bridge, with no interaction with internal VoIP audio conferencing. As a result, audio conferences can be completely PSTN or completely VoIP, but not a combination of both. Microsoft Office Communications Server

14 ACP integration is managed by the Telephony Conferencing Server, which always runs as a separate process on either a Standard Edition server or Enterprise Edition front-end server. Integration with the Audio Conferencing Provider occurs by configuring a federated connection with the external service provider, as you would with any other federated partner. Interoperability with Partners Office Communications Server 2007 has an extensible architecture that allows partners to develop software features and dedicated hardware that interoperates with Office Communications Server This architecture supports the interoperability of: Dedicated audio conferencing devices. These partners provide dedicated hardware devices that can participate in VoIP voice conferences with Office Communicator 2007 clients. Dedicated videoconferencing devices. These partners provided dedicated hardware devices that can participate in videoconferences with Office Communicator 2007 clients. Interoperating with these vendors is the focus of this white paper. H.323 videoconferencing devices. These partners provide gateway services that allow H.323-based (and in some cases H.320-based) devices to participate in videoconferences with Office Communicator 2007 clients or other native endpoints. Office Communications Server 2007 Interoperability with Videoconferencing Vendor Solutions The current interoperability between Office Communications Server 2007 and videoconferencing vendors is accomplished by each vendor. An example of this interoperability is the videoconferencing solutions provided by TANDBERG and Polycom. Office Communications Server 2007 Interoperability with TANDBERG Solutions TANDBERG, a global visual communications company, provides videoconferencing products and services in more than 90 countries worldwide. If an organization has an existing TANDBERG videoconferencing solution, they can interoperate with Office Communications Server 2007 with minimal effort. Note: Although TANDBERG is used an example in this white paper, similar solutions exist for other videoconferencing hardware vendors. Although the details for interoperability vary on a vendor-by-vendor basis, the concepts for interoperability are the same. Microsoft Office Communications Server

15 Overview of TANDBERG-based Solutions The following figure illustrates a typical TANDBERG-based videoconferencing solution. Figure 5. Typical TANDBERG-based videoconferencing solution Microsoft Office Communications Server

16 The following table lists the components that are included in the solution illustrated in Figure 5. Table 3. Components in a TANDBERG-based videoconferencing solution Component TANDBERG MXP Endpoints TANDBERG Video Communication Server (VCS) Control and TANDBERG VCS Expressway TANDBERG Codian MCU 4500 Description These components are a family of dedicated standards-based videoconferencing hardware endpoints (clients) that support SIP and H.323 and can be used with other TANDBERG products as well as other standards-based videoconferencing products. They range from complete Telepresence systems to high definition personal appliances for the executive desktop. These components bridge the gap between SIP and H.323 and deliver three unique applications in one centralized device. These components provide video call forwarding capabilities, support both SIP and H.323, and facilitate the migration to SIP. The TANDBERG VCS Control is the TANDBERG implementation of the gatekeeper functionality within the TANDBERG solution. The TANDBERG VCS Expressway is the TANDBERG implementation of the border controller function that provides network access translation (NAT) and firewall traversal. This component connects multiple audio and video sites in one or more ISDN, IP and mixed ISDN and IP videoconferences (including H.323 and SIP-based endpoints). Interoperability with Office Communications Server 2007 Currently the interoperability of TANDBERG-based solutions with Office Communications Server 2007 is provided by TANDBERG components. The following figure illustrates the interoperability of a TANDBERGbased videoconferencing infrastructure with Office Communications Server 2007 and Office Communicator 2007 clients. Microsoft Office Communications Server

17 Figure 6. Interoperability of Office Communications Server 2007 in a TANDBERG-based solution To provide videoconferencing interoperability between Office Communicator 2007 clients and clients in the TANDBERG infrastructure, the following happens: 1. Office Communicator 2007 clients register their presence status with the pool of servers running Office Communications Server In this configuration, the Office Communicator 2007 clients perform as they would in a solution that only includes Office Communications Server The clients are unaware that the TANDBERG infrastructure exists. Microsoft Office Communications Server

18 2. TANDBERG endpoints register their presence status with the TANDBERG VCS and the pools of servers running Office Communications Server Current versions of TANDBERG endpoints have the ability to register directly with Office Communications Server by using SIP. To provide interoperability with H.323 clients and other legacy endpoints, these endpoints also register with the TANDBERG VCS. The TANDBERG VCS functions as a SIP proxy, H.323 gateway, and H.323 gatekeeper. 3. Legacy endpoints register their presence status with the TANDBERG VCS. These endpoints must register with the TANDBERG VCS to participate in videoconferences with Office Communicator 2007 clients and current TANDBERG endpoints. The endpoints appear as H.323 clients to the TANDBERG VCS. 4. TANDBERG Codian MCU 4500 registers the presence of virtual conference rooms with Office Communications Server A TANDBERG virtual conference room is a video conference between two or more individual endpoints. The TANDBERG virtual conference rooms allow multiple point-topoint connections with Office Communicator 2007 clients to conference with other TANDBERG-based endpoints as well as videoconferencing endpoints from other vendors. The following figure illustrates how the presence status of individual TANDBERG endpoints and virtual conference rooms displays in Office Communicator From an Office Communicator 2007 perspective, the TANDBERG endpoints and virtual conference rooms appear as other Office Communicator 2007 contacts. Figure 7. Presence status of TANDBERG endpoints in Office Communicator 2007 Microsoft Office Communications Server

19 Videoconferences between these clients are accomplished either as point-to-point calls between Office Communicator clients and the TANDBERG MXP endpoints or as a multiparty conference through the TANDBERG Codian MCU The TANDBERG Codian MCU 4500 allows Office Communicator 2007 clients to conference with the current TANDBERG endpoints and legacy endpoints (such as H.323 and H.320 based endpoints). Although the solution in Figure 6 provides a level of interoperability between the Office Communications Server 2007 infrastructure and TANDBERG infrastructure, there are some limitations to the solution. The following table lists some limitations of the current interoperability between Office Communications Server 2007 and TANDBERG-based infrastructure. Table 4. Limitations of the current interoperability between Office Communications Server 2007 and TANDBERG-based infrastructure Limitation Office Communicator 2007 endpoints can only perform pointto-point videoconferences with TANDBERG infrastructure Only Office Communicator 2007 endpoints within the intranet can participate in videoconferences with TANDBERG endpoints Description Currently, only point-to-point videoconferences are supported between Office Communicator 2007 endpoints and the TANDBERG infrastructure. However, one of the endpoints in the videoconference could be a TANDBERG virtual conference room, which may in turn have other endpoints connected to the virtual conference room. Currently, Office Communicator 2007 endpoints that are outside the intranet, such as users on federated networks or the Internet, are only able to participate in videoconferences with Office Communicator 2007 endpoints within the intranet through the A/V Edge Server. In future releases, Office Communicator 2007 endpoints outside the intranet will be able to communicate with TANDBERG endpoints. For more information, see the How Microsoft Envisions the Future of Videoconferencing Interoperability topic later in this paper. Office Communications Server 2007 Interoperability with Polycom Solutions Polycom Inc. is one of the worldwide leaders in unified communication and collaboration solutions. Polycom is one of the earliest partners with Microsoft within the conferencing and collaboration industry. If an organization has an existing Polycom videoconferencing solution, they can interoperate with Office Communications Server 2007 with minimal effort. Note: Although Polycom is used an example in this white paper, similar solutions exist for other videoconferencing hardware vendors. Although the details for interoperability vary on a vendor-by-vendor basis, the concepts for interoperability are the same. Microsoft Office Communications Server

20 Overview of Polycom-based Solutions The following figure illustrates a typical Polycom-based videoconferencing solution. Figure 8. Typical Polycom-based videoconferencing solution Microsoft Office Communications Server