Deploying H.323 Conferencing on Your IP Network

CUseeMe Networks Technology White Paper Deploying H.323 Conferencing on Your IP Network Seeing, Hearing, and Sharing Across Networks Table of Contents Table of Contents... 1 Introduction... 2 What is the H.323 Standard?... 2 Why is the H.323 Standard Important?... 2 Planning for Deployment of the H.323 Standard... 3 Evaluate Current Network Capacity... 3 Characterize the type and frequency of H.323-based conferencing... 4 Understanding the audience... 4 Conference variables... 4 Audio... 4 Video... 5 Data... 5 Number of conferencing client endpoints to deploy... 5 Review Firewall Design... 6 Implementing QoS Measures... 6 Deploying Gatekeepers... 7 Linking distributed MCUs... 7 The Four Phases of Deployment... 8 Phase 1: Pilot test on a dedicated LAN... 8 Phase 2: Extend to LAN/WAN... 8 Phase 3: Secure H.323-based conferencing over the Internet... 9 Phase 4: Incorporate H.320-protocol endpoints via gateways... 9 The CUseeMe Networks Solution... 9 Conclusion... 10 About CUseeMe Networks, Inc.... 10 Sources of Additional Information... 11 Legal and Contact Information... 11 www.cuseeme.com World Headquarters CUseeMe Networks, Inc. 542 Amherst Street Nashua, NH 03063 T 603 886 9050

Introduction Since 1990, when the technology first became available, Fortune 500 companies have invested large sums of money in dedicated H.320-based videoconferencing systems and the networks to support them. Executives at these companies recognized the value of meeting face-to-face with key customers, suppliers, and employees. Reduced travel costs, shortened decision-making cycles, and increased productivity (due to less time spent away from the office) justified the expense of these costly systems. Despite its benefits, circuit-switched videoconferencing based on the H.320 suite of communications standards has seen limited deployment. Small groups of high-level managers within large enterprises have been the main beneficiaries of this communications medium. Meanwhile, demand has been building for a less-costly, more broad-based implementation of real-time, two-way multimedia communications. With this demand have come new communications standards and advances in computer technology. Faster processors, better audio and video compression schemes, and access to high speed connectivity networks have made it possible to integrate audio and video into the personal computing environment. Corporations today are leveraging their existing local and wide area networks (LANs/WANs) as well as the Internet to bring voice, video, and data conferencing to their work force, partners, and customer base. Real-time multimedia applications are being delivered on computer desktops over the same packet-based networks as more traditional LAN applications such as e-mail and file transfer. As more videoconferencing clients become available from a variety of different vendors, interoperability becomes increasingly important. The H.323 suite of communications standards is providing the framework for this interoperability. What is the H.323 Standard? The H.323 standard serves as the umbrella for a suite of recommendations defined by the International Telecommunication Union (ITU). The H.323 standard defines multimedia conferencing over packet-switched, generally IPbased, networks such as LANs/WANs and the Internet. It covers both point-to-point and multipoint conferencing. The specifications that fall under the H.323 standard umbrella define several components for real-time multimedia communications over packet-based networks. These include: Terminals: H.323-protocol terminals are client endpoints that provide real-time, two-way communications. Videoconferencing clients such as CUseeMe Networks CUseeMe Pro, CUseeMe Web, and CUseeMe for Windows; Intel ProShare and TeamStation ; Microsoft NetMeeting ; PictureTel LiveLAN ; Polycom ViewStation ; Sun Microsystems SunForum ; VTEL Galaxy and SmartStation; Zydacron Z350 and Z360; and others are H.323-protocol terminals. Gatekeepers: H.323-protocol gatekeepers are networklevel administration servers that provide call control services to H.323-protocol endpoints (an endpoint can be a terminal, gateway, or multipoint control unit). Services that gatekeepers provide include address translation, admissions control, bandwidth control, and zone management. CUseeMe Networks CUseeMe Conference Server has an integrated H.323-protocol gatekeeper. Gateways: H.323/H.320-protocol gateways enable H.323- protocol endpoints to communicate with non-h.323-protocol endpoints by providing translation between packet-based networks and circuit-switched networks (examples of circuit-switched networks include Public Switched Telephone Network (PSTN) and Integrated Services Digital Network (ISDN); note that the H.324 standard applies to PSTN and the H.320 standard applies to ISDN). CUseeMe Networks CUseeMe Conference Server is an H.323/H.320- protocol gateway, as well as a CUseeMe-protocol/H.323- protocol gateway. Multipoint Control Units (MCUs): H.323-protocol MCUs provide support for multipoint conferences between three or more endpoints. An MCU consists of a Multipoint Controller (MC) and optional Multipoint Processors (MP). The MC negotiates with endpoints to achieve common levels of communication for the multipoint conference. The MP allows mixing, switching, or other processing of media streams from connected endpoints. CUseeMe Networks CUseeMe Conference Server is an example of a softwarebased MCU with an integrated gatekeeper. In order for a terminal to be compliant with the H.323 standard, it must support voice communications and can optionally support video and/or data. The H.323 specification references other ITU specifications for all aspects of the conference, including gatekeeper signaling (H.245), call signaling (Q.931), call control (H.245), media control (H.225), audio (G.7xx series), video (H.2xx series), and data (T.120 series). Why is the H.323 Standard Important? In May of 1996, the ITU ratified the H.323 standard for real-time multimedia communication and conferencing over packet-based networks. In January of 1998, it ratified Revision 2 of the standard, which added clarification and enhancements to the original recommendation. With the ratification of the H.323 standard, we now have a common protocol that allows communications products offered by different vendors to work together. While this sounds simple on the surface, its impact on the videoconferencing market should not be underestimated. With users from around the globe communicating via hardware and software from a variety of vendors, industry standards are required to ensure interoperability. Without a comprehensive H.323 Technology White Paper Page 2

standard such as the H.323 standard, many customers would not be willing to deploy conferencing on their IP networks. In addition to providing essential interoperability between communication endpoints, real-time H.323-based conferencing over IP networks provides the following key benefits: The ability to integrate multimedia communications directly with other IP applications. The H.323 standard allows the integration of T.120-based data conferencing, creating new ways to collaborate in the corporate world. Users can share applications, mark up shared whiteboard documents, and perform file transfers during the course of an H.323-based videoconference. Users work can be done real-time instead of being delayed until participants return to their offices. New ways to use the technology including distance learning, home-office meetings, face-to-face customer support, and direct sales expansion. Users are analyzing their current business practices and discovering new applications every day. Protection of investment in legacy conference systems. Gateways that go from H.320-based environments to H.323-based environments bridge ISDN (circuit-switched) and IP (packet-based) networks. Conference systems that reside on H.320-based networks can now conference with H.323-based systems. Leveraged investment in existing corporate network infrastructure. Traditional H.320-based conferencing systems require dedicated ISDN lines for each conference room or office. The H.323 standard can be deployed wherever Internet Protocol (IP) is supported. Corporations are increasingly migrating communications onto a single IPbased network, eliminating the cost and complexity of maintaining multiple communication networks. Scalability. The H.323 standard takes advantage of increased hardware performance and faster connectivity to improve software performance. A user can upgrade to a faster network connection or faster CPU and get a better videoconferencing experience from existing H.323-protocol software. Long-distance savings. The H.323 standard allows you to place long distance videoconferencing calls over fixed-cost IP networks. Traditional H.320-based conferencing requires dial-up ISDN service with incremental usage charges. Convenience to the user. The H.320 standard has traditionally meant expensive, room-based systems, requiring the user to go to the technology. The H.323 standard can be integrated cost-effectively into users existing desktop computers. The technology is only a button-click away. Increased productivity. H.323-based desktop systems are used throughout the day for general business purposes when users are not participating in videoconferencing calls. Dedicated H.320-based conferencing systems sit idle when there is no videoconference in session. Planning for Deployment of the H.323 Standard The requirements that real-time multimedia conferencing place on a network are different than that of traditional IP traffic. Bandwidth and consistent quality of service are primary. However, with proper evaluation and planning, many organizations will find that their existing network infrastructure can adequately support a rollout of H.323-based conferencing A network administrator should take the following steps before deploying H.323-based conferencing. Each is described in more detail later in this section. Evaluate current network capacity. How much bandwidth do you have available? Characterize the type and frequency of H.323-based conferencing. How much bandwidth will be consumed? How many conferencing clients can you safely deploy? Review existing firewall design. Does your firewall support H.323-protocol traffic? Implement measures to guarantee the desired Quality of Service (QoS) for H.323-based conferencing. Evaluate Current Network Capacity The first step in planning for H.323-based conferencing is to determine the amount of bandwidth currently being consumed on your LAN/WAN, and what amount is available for conferencing. Evaluating current network capacity is fairly straightforward today, with the many network diagnostic tools available. It is important to evaluate current usage on all segments of your network and identify any potential bottlenecks. The following are some questions you should ask: What is the full duplex bandwidth capacity for each segment of your network, including WAN links to remote offices? For example, 10 megabits per second (Mbps) for 10BaseT Ethernet LAN, 3.08 Mbps for a T1 (1.54 x 2). What is the current bandwidth load, averaged over the busiest hour of the day, for each segment? What is the maximum bandwidth load you are comfortable with for each segment? Many network administrators feel Shared Ethernet LAN segments should not be loaded to more than 35-40% of capacity in order to accommodate spikes in usage. What is the difference between the current bandwidth load and the maximum bandwidth load you want to allow on your network? This is the amount of bandwidth you currently have available for the deployment of H.323-based conferencing. H.323 Technology White Paper Page 3

You may be able to increase available bandwidth on your local LAN with modest updates to your infrastructure. Refer to Implementing QoS Measures later in this document for some suggestions. Characterize the type and frequency of H.323- based conferencing The second step in planning for deploying the H.323 standard is to determine how much bandwidth you expect conferencing to consume. Once you have determined this, you can make some calculations as to how many conferencing clients can be safely deployed on your existing network, or to determine whether to make upgrades to your network to accommodate increased traffic. There are many different parameters you need to look at in determining bandwidth requirements for H.323-based conferencing. These include: What is the base number of simultaneous calls you expect on your network? What type of client endpoints will be conferencing on your network? In what type of conferences will these endpoints participate? What is the desired audio/video quality level for these conferences? Understanding the audience In order to determine bandwidth requirements for H.323-based conferencing, you must define user application needs for your organization. This involves getting a clear understanding of how multimedia conferencing will be used in your organization, how often, and by how many. For instance, small two-way interactive sales conferences with several remote participants on a daily basis will have much different requirements than a CEO s quarterly communication to employees at multiple sites around the world. Will your users be interacting via audio and video only, or will they also be data conferencing? Will conferences be two-way interactive or one-way broadcast? Will video be primarily talking heads (where the image does not change much from frame to frame), or will it involve a lot of motion? Will users be videoconferencing regularly throughout the day, or only occasionally for scheduled conferences? Understanding these issues will help you determine the base number of simultaneous calls to expect on your network, bandwidth requirements for those calls, how many and what kind of client endpoints to deploy, and appropriate MCU and gatekeeper/gateway configurations for your network. Conference variables Bandwidth requirements for interactive multimedia conferences vary widely, influenced in large part by the following factors: The kinds of media used in the conferences. An audio-only H.323-based conference will obviously use much less bandwidth than a conference that also employs video and/or data conferencing. The types of codecs (COmpression/DECompression algorithms) used by client endpoints in the conference. Table 1 shows the individual standards, including audio/video codec standards, supported by the H.320 and H.323 standards. User-configurable parameters. These include video resolution, frame rate, and sound quality. Given these variables, it is difficult to state an average bandwidth for a multimedia conference. However, understanding these variables will help you to make educated estimates of bandwidth requirements. Type Network Audio G.711 G.722* G.728* Video H.261 H.263* H.320 Standard supports Narrowband, circuitswitched (ISDN) H.323 Standard supports Packet-switched, nonguaranteed QoS (IP) G.711 G.722* G.723.1* G.728* G.729* H.261 H.263* Data T.120 T.120 Multiplexing H.221 H.225.0 Control H.230 H.242 H.245 Table 1. H.320/H.323 Codec Comparison Chart *Optional Audio H.323-based terminals must support the G.711 audio codec for speech compression. This is required by the standard for interoperability between H.323-protocol and H.320-protocol endpoints. The standard defines additional audio codecs as optional (see Table 1 for a complete listing). The G.711 audio codec transmits voice at either 56 or 64 kilobits per second (Kbps). The G.711 codec is well suited for high bandwidth environments. However, bandwidth is often a concern in a LAN/WAN setting, and the G.723.1 audio codec is becoming a popular option in H.323-protocol applications. The G.723.1 audio codec offers somewhat inferior audio quality to the G.711 codec, but offers much better compression, requiring only 5.3 or 6.4 Kbps of bandwidth. H.323 Technology White Paper Page 4

Video If an H.323-based terminal supports video, it must support the H.261 codec for video compression. This is required by the standard for interoperability between H.323-protocol and H.320- protocol endpoints. The standard defines H.263 and H.263+ video codecs as optional. The H.261 codec generally provides less compression and therefore requires more bandwidth than the H.263 codecs. The H.263 codec was designed to be more resilient to packet loss. It therefore provides better image quality in low bandwidth environments and also offers more video resolution options. When you specify a video codec for an H.323-based conference, you also need to specify the video resolution that the codec will use to send and receive. Table 2 describes the video resolution formats supported by the H.261 and H.263 codecs. In general, greater image resolution requires greater bandwidth to transmit and receive. Video Format Sub-QCIF (Sub-Quarter Common Intermediate Format) QCIF (Quarter Common Intermediate Format) CIF (Common Intermediate Format) Image Resolution (Pixels) H.261 Codec 128 x 96 176 x 144 352 x 288 * * 4CIF 702 x 576 * 16CIF 1408 x 1152 * H.263 Codec Table 2. Video Resolutions Supported by H.261 and H.263 Codecs *Optional Videoconferencing calls can vary in send and receive bandwidth from 57.6 Kbps to 800+ Kbps, depending on the video frame rate and the quality of image. These factors are affected by the video compression scheme used by the client endpoint and can be selected by the user within the multimedia bandwidth constraints set by the network administrator. Users can choose to optimize video quality (sharpness or clarity), frame rate (motion), or bandwidth use. Note: Support for optional H.323 video codecs differs from client to client. Some vendors implement only the required H.261 codec, while other vendors implement variations of the H.263 codec as well. Data T.120-protocol data conferencing applications such as file transfer, whiteboard, and application sharing, have widely varied bandwidth requirements. Unlike audio and video, which require consistent bandwidth performance, data applications tend to require bandwidth in bursts and can tolerate slow-downs in network performance. When a user opens a new whiteboard document, for example, bandwidth will spike for a few seconds and then average out. If the network is congested, a user s mark-ups to a document will take longer to travel over the network but will eventually arrive on the whiteboards of connected participants. Despite its bursty nature, data conferencing can take up significant network resources and should not be left out of the bandwidth requirement equation. Find out what data conferencing applications your users will be using and perform some bandwidth usage tests with these applications in a videoconferencing environment. Number of conferencing client endpoints to deploy Once you have determined available bandwidth and the characteristics of your conferencing clients, some simple calculations can help you determine the maximum number of clients that can be safely deployed. A client s send/receive rates are determined by the audio/video codec settings for the conference. By dividing available bandwidth by the send/receive rates of the client, you get the maximum number of clients that can simultaneously videoconference on your network. For example, H.323-protocol clients could participate in a high quality videoconference using the G.711 audio codec and H.261 CIF video codec. Each client would consume approximately 400 Kbps of bandwidth in each direction (send/receive). Assuming a normal load of 40% on a 10 MB Shared Ethernet network, five clients could conference simultaneously without negative impact on the network. Note that the number of users could increase dramatically for conferences in which send/receive rates are lower, or for conferences where users are connected via Switched Ethernet rather than Shared Ethernet. Table 3 provides some client connection estimates per available bandwidths. A variety of conference quality levels are explored. The 100 MB and 10 MB columns assume a maximum 40% network load on Shared Ethernet networks. The T1 column assumes 100% full duplex utilization (1540 Kbps x 2). H.323 Technology White Paper Page 5

Client Connection to Conference High Quality Video Conference (384 Kbps) Medium High Quality Video Conference (256 Kbps) Medium Low Quality Video Conference (128 Kbps) Low Quality Video Conference (64 Kbps) High Quality Video Chat (56 Kbps) Low Quality Video Chat (28.8 Kbps) Client Full Duplex Bandwidth Maximum # of Client Connections on 100 MB Shared Ethernet (40000 Kbps) Maximum # of Client Connections on 10 MB Shared Ethernet (4000 Kbps) 768 52 5 4 512 78 8 6 256 156 16 12 128 313 31 24 84.8 472 47 36 57.6 694 69 53 Maximum # of Client Connections on T1 Connection (3080 Kbps) Table 3. Client Connections per Available Bandwidth Review Firewall Design Firewall devices are designed to protect your organization s network from unwanted computer access. If your organization has a firewall set up, or is planning to implement one, you need to determine the following: Can the firewall be programmed to pass H.323-protocol multimedia traffic? In contrast to data traffic, which is carried over TCP connections, the H.323 protocol uses a combination of TCP and UDP ports. An H.323-protocol call is made up of numerous simultaneous connections; it uses a static port for call connection and multiple dynamic ports. Consult your firewall documentation or contact your firewall vendor to find out whether your firewall supports H.323- protocol traffic. Does the firewall have enough bandwidth to carry H.323- protocol multimedia traffic? Multimedia traffic can have greater continuous bandwidth than data traffic. Note: A port refers to a specific location within a computer s TCP/IP stack. Programs that communicate over computer networks use different port numbers to help keep the data they are sending separate from data sent by other programs communicating to the same IP address. Single programs might use several different ports each for a different activity. Implementing QoS Measures Once you have determined your current network capacity and how much bandwidth is available for videoconferencing, you are ready to prepare your network for deploying the H.323 standard. As network administrator, you can control the Quality of Service (QoS) on your LAN/WAN through proper engineering of your IP network. Suggestions include: Use 10BaseT or 100BaseT Ethernet to connect individual endpoints to the LAN. 10BaseT operates at a maximum speed of 10 Mbps (10,000,000 bits per second). 100BaseT operates at a maximum speed of 100 Mbps (100,000,000 bits per second). Provide 100BaseT Ethernet to your MCUs and gatekeepers. Upgrade from a Shared Ethernet LAN to a Switched Ethernet LAN. LAN segments are often shared among multiple users. The most cost effective way to add bandwidth is to spread your users across multiple Ethernet switches. An Ethernet switch isolates traffic between different users so that heavy demand from one user doesn t slow down performance for others. Provide a dedicated always on connection from your LAN to your WAN and/or the Internet. Use the same network service provider at every location on your WAN, so that data stays on your provider s private network. Schedule WAN traffic appropriately so as not to create conflicts. For H.323 Technology White Paper Page 6

example, schedule jobs that are not time sensitive so they consume bandwidth off hours. Use routers that give audio and video priority over non-realtime data such as e-mail and file transfer. Optimize multipoint conference configurations on your MCU for the type of endpoints you expect. Choose appropriate audio/video codecs for the bandwidth and connection speeds available. Set up separate conferences for low bandwidth and high bandwidth clients when applicable. If you are planning to purchase new network components, be sure to research device latency statistics between different products before buying. Audio/video communication requires low latency (accumulated delay) between sender and receiver in order to maintain quality. This is because audio and video data lose relevancy to the receiver if not delivered in a timely manner. Each component on a network introduces some amount of latency. Excessive delay occurs when one or more of these components are not working at desired capacity. Routers, switches, and other network devices from different vendors introduce different amounts of latency. Factor in native performance of the systems you plan to use for deploying the H.323 standard. CPU cycles, memory use, and the I/O (input/output) subsystem can limit throughput on both client and MCU systems. However, keep in mind that a client system has only to deal with its own load, while an MCU must be able to deal with added users. Numerous commercial tools are available to gather data about system usage. rules for deciding which endpoints can register with a gatekeeper are left to the network administrator. Network administrators assign each segment of their LAN/WAN to a particular gatekeeper zone. The administrator then allocates to that zone, the desired amount of bandwidth for conferencing traffic. When an H.323-protocol call is made, the gatekeeper accepts or rejects it based on current network load at the time. This allows a network administrator to make realtime multimedia conferencing available to many users without fear of overloading the network. Linking distributed MCUs A single Multipoint Control Unit can do a lot to optimize the use of resources on your network. However, bandwidth savings can be even more dramatic when MCUs are used to distribute the communications load over a wide area network or the Internet. Figures 1 and 2 provide a comparison to illustrate local replication. Both figures illustrate a videoconference with four participants, one located at the corporate head office and three located in a remote office (for simplicity of illustration, we have shown communications flowing in one direction only). The following sections provide information on additional measures that you can take to assure the quality of service on your network for deploying the H.323 standard. Deploying Gatekeepers Gatekeepers are key elements in maintaining the quality of service for H.323-based conferencing. Services that gatekeepers provide include: Address Translation: Gatekeepers perform alias-address to transport-address translation. Endpoints register one or more aliases with a gatekeeper. Other endpoints then query the gatekeeper for a desired alias. Admissions Control: H.323-protocol endpoints send RAS (Registration, Admission, and Status) messages to a gatekeeper. The gatekeeper authorizes network access to these endpoints. Figure 1. Single Server Conference over Wide Area Network In Figure 1, the conference uses a single MCU located at the corporate office. Three copies of the corporate office participant s data traverse the unicast WAN one copy for each recipient at the remote office. In Figure 2, each office has a local MCU. Participants connect locally and the MCUs communicate to each other across the unicast WAN. A single data stream of the corporate office participant is sent over the WAN. The MCU then replicates the data stream to each recipient on the remote office s LAN. This saves considerable bandwidth on costly WAN links. Bandwidth Control: Terminals send requests for network bandwidth to the gatekeeper. The gatekeeper grants or denies these requests based on bandwidth allocation limits set by the network administrator for that gatekeeper s zone. Zone Management: A gatekeeper is required to provide address translation, admissions control, and bandwidth control to all endpoints that have registered with it. The H.323 Technology White Paper Page 7

Conduct a small multipoint conference on your MCU. Connect three endpoints through the gatekeeper to start. Use network monitoring devices to determine how much actual bandwidth is being consumed. Continue to add client endpoints to the multipoint conference, one at a time. Check performance and bandwidth use with each client you add. Figure 2. Local Replication Note: Distributed server linking is a feature of CUseeMe Networks CUseeMe Conference Server. Unlike the CUseeMe Conference Server, most H.323-protocol MCUs are not designed to link together. They are designed for a centralized deployment model. In the centralized model, a single MCU handles all of the conferencing requirements for a network. If demand for conferencing increases, MCUs can be added to the network but cannot share conferences across servers, take advantage of bandwidth savings inherent to linking (such as local replication), or be centrally administered through a single server. In a centralized model, the demands of H.323-based conferencing can quickly saturate the network. A decentralized model, with distributed server linking, takes into consideration the major factors that affect bandwidth use and network performance in the IP environment. The Four Phases of Deployment With your network optimized for H.323-based conferencing, you are now ready to deploy it within your organization. The following four phases outline the steps you should take in deploying the H.323 standard on your network. Take time to test performance on your network as you complete each phase. This will help you identify and isolate any potential problems. Phase 1: Pilot test on a dedicated LAN Figure 3 illustrates a small deployment of the H.323 standard on a dedicated LAN segment. Figure 3. Dedicated LAN Deployment Phase 2: Extend to LAN/WAN Once you have pilot tested your H.323-based system in a LAN environment you can extend a small-scale deployment to your WAN. Install client endpoints at remote locations on your wide area network. Connect these clients over your WAN to your MCU. Check performance and bandwidth use with each client you add. To optimize bandwidth over your WAN and distribute the bandwidth load, install an MCU in each remote location. Connect client endpoints to their local MCU and link MCUs across WAN links. Figure 4 illustrates a deployment of the H.323 standard over a LAN/WAN. Before deploying H.323-based conferencing to your organization as a whole, conduct a small pilot test on a dedicated LAN segment. Install client endpoints and test in a point-to-point conference to make sure clients are configured properly and can establish an H.323-protocol connection. Ensure that clients are set with proper audio and video codecs and performance is acceptable. Install and start the MCU and the gatekeeper that will control multipoint conferencing on your network. Do this on the same subnet on which you installed the H.323-protocol clients. Allocate bandwidth as determined in your predeployment planning stages. H.323 Technology White Paper Page 8

Phase 4: Incorporate H.320-protocol endpoints via gateways You can connect H.320-protocol traffic to your H.323-based conferencing network through an H.323/H.320-protocol gateway. Setup an H.323/H.320-protocol gateway device on your network. Gateways create a bridge between packet-based and circuit-switched networks, enabling H.323-protocol endpoints to communicate with H.320-protocol endpoints. Allow H.320-protocol client endpoints to connect through the gateway to multipoint H.323-based conferences controlled by a gatekeeper and MCU on your corporate network. Figure 4. Distributed H.323 Multipoint Deployment Figure 6 illustrates H.323-based conferencing deployed over a LAN/WAN, and the Internet, and incorporating circuit-switched H.320-protocol traffic through a gateway. Phase 3: Secure H.323-based conferencing over the Internet With H.323-based conferencing working over your corporate LAN/WAN, you can now extend it to clients over the Internet. If your organization has a firewall, configure it to accept H.323-protocol traffic. Allow H.323-protocol client endpoints to connect to multipoint conferences controlled by a gatekeeper and MCU on your corporate network, traversing your firewall if applicable. Figure 6. H.320-protocol Endpoints Incorporated into H.323-protocol Network The CUseeMe Networks Solution CUseeMe Networks develops real-time multimedia conferencing applications tailored to business, education, and training. The CUseeMe Conference Server is CUseeMe Networks software-based, multipoint control unit with an integrated H.323-protocol gatekeeper. Figure 5. Secure H.323-based conferencing deployed over a LAN/WAN and the Internet. It allows groups of users with networked personal computers to interact in real-time, sharing any combination of audio, video, and T.120 data. H.323 Technology White Paper Page 9

It allows administrators to control the use of multimedia communications on their network, offering them bandwidth control and optimization, security, conference administration, and monitoring services. The CUseeMe Conference Server provides multipoint conferencing services to H.323 standards-based clients such as CUseeMe Networks CUseeMe Pro; Microsoft NetMeeting; Intel Business Video Conferencing with ProShare; Intel TeamStation; and PictureTel LiveLAN. Participants can use a variety of videoconferencing clients to work, learn, and socialize in a multipoint conferencing environment. As a company, CUseeMe Networks has its roots in the world of IP-based client/server software, and was the first vendor to offer a software-based H.323-protocol MCU. Integrated Gatekeeper Multi-platform Support (UNIX & Windows) User Access Management Conclusion CUseeMe Conference Server s integrated gatekeeper allows administrator s to set bandwidth limits for conferencing on their network. CUseeMe Conference Server can also be configured to use the services of a third-party gatekeeper, instead. Provides flexibility in deployment by allowing administrator to choose the operating system best suited for the application/environment. Allows administrator control over who can access which conferences, at what time of day, and who can schedule conferences. CUseeMe Networks designed the CUseeMe Conference Server for a decentralized model of deployment, where multiple, distributed MCUs serve to balance the videoconferencing load on a network. The CUseeMe Conference Server s intelligent bandwidth management features, such as distributed server linking, help to optimize videoconferencing for today s existing network topologies. Major benefits of CUseeMe Networks CUseeMe Conference Server include the items in the following table. Feature Standards-based Software-based Web-based Interface Server Domains Server Linking Bandwidth Pruning and Scalability Third-party Billing Support Data Sharing Benefit Uses your existing IP network to connect multiple standards-based conferencing clients over your Intranet, the Internet, or through an H.323/H.320-protocol gateway. Allows flexibility of deployment in a scalable, cost effective manner. Administrators can add, edit, and moderate conferences from anywhere via a Web browser. Administrators can centrally administer a group of distributed CUseeMe Conference Servers associated with a single domain, through the Web-based interface. CUseeMe Conference Servers can be linked so that several servers can share a conference across the LAN/WAN or the Internet. This allows network administrators to load balance conference data across the network. The CUseeMe Conference Server determines when to prune, or intelligently discard, IP packets so as not to flood endpoints. In addition, the CUseeMe Conference Server can mix different users connection speeds without dropping overall performance to the lowest common denominator. Allows organizations to roll out fee-based conferencing services. Users can integrate videoconferencing with other IP-based applications. Real-time, two-way multimedia communications are being deployed on IP networks today. The arrival of H.323-based conferencing solutions has opened up a new world of communications possibilities. User applications include everything from distance learning, videochat, customer service, and recruiting to legal consultation, loan origination, and board meetings. With every day, more and more people have easy access to H.323-based conferencing tools. Increasingly, desktop computers come from the factories multimedia ready. And, in many retail stores, users can obtain software and hardware that enables visual communications over the Internet for under $100. With this convergence of technology and application, corporations are looking for ways to deploy H.323-based conferencing without negative impact on existing networks. CUseeMe Networks CUseeMe Conference Server provides the necessary tools to do this. Features such as distributed server linking and gatekeeper functionality allow network administrators to control the impact of videoconferencing on their organization s network. Through up-front evaluation and planning, corporations today are successfully integrating H.323-based conferencing into their existing networks providing a valuable new method of communication to their employees, partners, and customer base. About CUseeMe Networks, Inc. CUseeMe Networks develops, markets and supports multiplatform, browser-based, internetworking software that facilitates worldwide video and audio communication and data collaboration across the Internet, intranets, extranets and other networks that use the Internet Protocol. Our videoconferencing software products, CUseeMe, CUseeMe Conference Server, and CUseeMe Web, create client-server solutions that allow users to participate in real-time, multipoint video, audio, and data conferences over the Internet and intranets. You can find H.323 Technology White Paper Page 10

CUseeMe Networks on the World Wide Web at http://www.cuseeme.com and experience our videochat technology at http://www.cuseemeworld.com. CUseeMe Services has an established list of charter customers including CUseeMe World, FaceTime Communications, Inclusion, Kensington, MAX i.c., National Computer Camps, Inc., Ricoh, ThinkTanks Worldwide, Time Warner, and TMG Corporation. CUseeMe Services charter customers represent a range of business types including corporations, Internet community sites, and ISPs/ASPs. Sources of Additional Information For the latest news about CUseeMe Conference Server from CUseeMe Networks and access to our searchable database of Frequently Asked Questions (FAQs), visit: http://www.cuseeme.com/software For information on the International Telecommunication Union, visit: http://www.itu.org For information on the Multicast Backbone (MBone), visit: http://www.ietf.org/ids.by.wg/mboned.html Legal and Contact Information Copyright 2000, CUseeMe Networks, Inc. All Rights Reserved. CUseeMe is a registered trademark, and CUseeMe Conference Server and CUseeMe Web are trademarks of CUseeMe Networks, Inc. Other products or company names mentioned herein may be trademarks or registered trademarks of their respective manufacturers. This paper is for informational purposes only. CUSEEME NETWORKS MAKES NO WARRANTIES, EXPRESS OR IMPLIED, IN THIS DOCUMENT. CUseeMe Networks is a publicly traded company on the NASDAQ Exchange using the symbol CUSM. For more information visit www.cuseeme.com and www.cuseemeworld.com World Headquarters CUseeMe Networks, Inc. 542 Amherst Street Nashua, NH 03063 USA T 603 886 9050 F 603 886 9051 European Headquarters CUseeMe Networks, SA 9551, route de Saint Laurent du Var 06610 La Gaude, France T +33.4.93.59.43.43 F +33.4.93.24.76.06 H.323 Technology White Paper Page 11