Real-World IP Network Convergence for Conferencing

Real-World IP Network Convergence for Conferencing

Considerations for Hosting IP Video on the Enterprise Data Network

Real-World Convergence for Conferencing Considerations for Hosting IP Video on the Enterprise Data Network

Ira M. Weinstein Wainhouse Research

July 2005

http://www.wainhouse.com/

Table of Contents

Executive Summary .................................................................................................................................... 1

Introduction................................................................................................................................................. 2

Why Migrate Video to IP? ......................................................................................................................... 3

The Enterprise Convergence Challenge ................................................................................................... 4

Convergence Considerations...................................................................................................................... 5 Network Security (Firewalls / DMZ) ....................................................................................................... 5 IP Addressing Scheme / Network Addressing Translation (NAT)........................................................... 7 Existing Network Traffic.......................................................................................................................... 8 Network Quality of Service (QoS) Capabilities ....................................................................................... 8 Routing Protocols and Routing Redundancy............................................................................................ 9 Network Elements & Hardware Redundancy ........................................................................................ 10 WAN Topology ...................................................................................................................................... 10 Lack of Ancillary Services ..................................................................................................................... 10

Forward Motion Options ......................................................................................................................... 12 Option 1 – Maintaining Status Quo........................................................................................................ 12 Option 2 – Network Convergence .......................................................................................................... 12 Option 3 – The Hybrid Solution ............................................................................................................. 12

Conclusion ................................................................................................................................................. 14

About Wainhouse Research ..................................................................................................................... 15 About the Author.................................................................................................................................... 15

About GlowPoint....................................................................................................................................... 15

Real-World Convergence for Conferencing Copyright © 2005 Wainhouse Research. All rights reserved.

List of Figures

Figure 1: Traffic Traversing H.323-“Capable” Firewalls ............................................................................. 5

Figure 2: Using an H.323 Proxy, ALG, or SBC Solution............................................................................. 5

Figure 3: Routing Video Traffic through ISDN Gateways........................................................................... 6

Figure 4: Using a Dedicated IP Video Network Overlay Solution............................................................... 6

Figure 5: A Typical IP Video Network Overlay Deployment ...................................................................... 7

Figure 6: Traffic Routing on a "Typical" Data Network .............................................................................. 9

Figure 7: Traffic Routing with Prioritization for Low Latency .................................................................... 9

Figure 8: GlowPoint’s Web Interface for Accessing Video Mail............................................................... 11

Figure 9: Bypassing Network Issues Using an Overlay Network............................................................... 13

Real-World Convergence for Conferencing Copyright © 2005 Wainhouse Research. All rights reserved.

Executive Summary

In recent years, the promise of enhanced productivity, improved communications, and potential cost savings has prompted many organizations that previously embraced an “in-person” meeting culture to reconsider their position and deploy (or evaluate) virtual meeting tools.

In addition, the proliferation of IP networks (and the benefits of IP-based conferencing) has encouraged many organizations to at least attempt to migrate their videoconferencing traffic from H.320-based ISDN to a converged network hosting voice, video, and data traffic. Unfortunately, for many enterprises this has been a difficult goal to reach for a variety of reasons, including limited availability of resources, a lack of uniformity within the WAN, and concerns about the impact conferencing traffic may have on other data sharing the same data pipe.

The above notwithstanding, it is entirely possible for organizations to host video traffic on their corporate network, but due diligence requires careful consideration of certain areas including:

Network security issues (firewalls, proxies, etc.)

IP addressing schemes and network address translation

Existing network capacity and traffic level

Ability for the network to provide the required Quality of Service (QoS)

Network routing protocols

Network elements and hardware redundancy

Current WAN topology (vendors, protocols, network peering)

Need for ancillary services (scheduling, call launching, monitoring, reporting, etc.)

Ideally, organizations embarking on such a project would conduct a thorough network assessment to highlight the network’s current status and document areas in need of remediation.

In most cases, organizations seeking to host video traffic on the corporate data network will be faced with four forward-motion options as follows:

Do Nothing - Maintain status quo (delay the migration of videoconferencing over to IP)

Global Convergence - Activate an enterprise-wide convergence initiative

Hybrid Solution - Selectively enhance certain parts of the network environment with a third party video overlay network.

Global Overlay Network - Utilize a dedicated, third-party IP video network to host all videoconferencing traffic.

While enterprise-wide convergence is certainly a reasonable long-term plan, many organizations will be unable to complete such an ambitious task in the near future. As such, Wainhouse Research expects many organizations to selectively enhance their network (depending upon the enterprise this may involve minor or significant investments or upgrades), or to deploy a dedicated IP network as a means to quickly decrease costs and improve reliability and performance.

Real-World Convergence for Conferencing

Copyright © 2005 Wainhouse Research. All rights reserved. Page 1

Introduction

Wainhouse Research believes that the convergence of voice, video, and data traffic onto the corporate data network should be a part of the corporate network strategy for virtually every large, distributed enterprise organization. While a detailed discussion of the justification for convergence is beyond the scope of this document, the obvious benefits of congregating these items onto a single network include:

Reliability – In converged environments, all management and monitoring systems are focused on a single network, which allows for faster problem discovery, troubleshooting, and resolution.

Manageability – Convergence allows an organization to utilize a single set of network management tools to manage and monitor its entire network.

Performance – Networks hosting voice, video, and data traffic typically include some form of Quality of Service (QoS) control, resulting in enhanced performance for demanding applications.

Cost Effectiveness – By eliminating the need for multiple networks, management / monitoring systems, and support staff, convergence typically yields significant cost savings.

Efficiency – Centralized network platforms allow organizations to leverage support resources on a global basis, thereby increasing the effectiveness of their support staff and minimizing support costs.

Scalability – The centralization of network resources and support resources allows an organization to scale their network without having to deploy additional management / monitoring systems and support resources.

Wainhouse Research believes that network convergence should be a part of virtually every

enterprise’s network strategy.

Strictly speaking, convergence includes the migration of both voice and video traffic from legacy, independent data networks (typically the “plain old telephone system” or “POTS” for voice, and ISDN for video) to the corporate LAN / WAN. For various reasons, including the bandwidth and QoS requirements, the migration of video tends to be more difficult for an enterprise to achieve.

This paper focuses on some of the areas that organizations must consider as they work toward running business quality videoconferencing on the corporate LAN / WAN.



Why Migrate Video to IP?

The first item worthy of discussion is why a company should seek to migrate their videoconferencing traffic from a legacy ISDN overlay network to IP. The answer lies in the difficulties and expense of ISDN-based videoconferencing, and the benefits of IP.

As of this writing, WR believes that the install-base of videoconferencing systems is still primarily running on global ISDN networks (although a significant percentage of newly purchased video endpoints are only IP-capable). Provided primarily by telephone companies (Telco’s) around the world, ISDN is an international communications standard for voice, video, and data over digital telephone lines.1 In many cases, ISDN service is delivered over normal telephone wiring, making it possible to provide these services to many locations around the world – including small offices and home offices.

Unfortunately, ISDN was not built to address (and in some instances has contributed to) many of the problems commonly associated with videoconferencing, including:

Reliability – ISDN videoconferencing involves placing multiple ISDN long-distance phone calls. Any glitch or disconnection on any of the individual phone calls can impact the entire videoconference.

Manageability – As a circuit-switched technology, it is difficult to manage or monitor ISDN lines when they are not connected.

Performance – ISDN video calls often suffer from quality problems, including frozen or tiled video images and distorted audio.

Scalability – Unless ISDN switching equipment is deployed (usually justifiable only for environments with a high volume of usage per system), each video system requires dedicated ISDN lines, which makes ISDN expensive and difficult to scale.

Cost Effectiveness – ISDN is a metered, pay-per-minute service which means that frequent videoconference users are burdened with high long distance bills. This is especially true for users making international videoconference calls.

These are just a few of the many drivers for migrating videoconferencing from traditional ISDN networks to the corporate LAN / WAN.

1 Source: webopedia.com, http://isp.webopedia.com/term/i/isdn.html



The Enterprise Convergence Challenge

Considering the obvious benefits of convergence, and the fact that IP video systems and IP networks have been widely available for years, why is the convergence of voice, video, and data onto a single IP network taking so long? The answer is that while convergence sounds wonderful, in reality it’s quite difficult for organizations to implement for reasons including:

Limited Resources – Many organizations have difficulty dedicating the necessary resources to a project of the magnitude required for convergence.

Non-Uniform Networks – Most enterprises utilize different type of networks (often from different vendors and offering different levels of performance) to reach their various offices. Since videoconferencing requires a high level of end-to-end network performance, convergence may require forklift network upgrades and/or new service contracts.

Lack of Experience – Until recently, videoconferencing was managed by telecommunications-focused professionals familiar with circuit-switched technologies. Today’s IT support staff expected to manage IP-based videoconferencing have limited experience in this area. This learning curve has slowed convergence efforts.

The “convergence conundrum” is that many organizations that could benefit from

convergence are unable to successfully complete a network convergence project.

Risk Management – By running all videoconferencing over ISDN lines, organizations could segregate video data from critical company data. Once migrated over to the corporate LAN, there is a risk that unless properly managed, the videoconferencing data could overwhelm network resources and step on critical network traffic.

Lack of Information – Many organizations have difficulty collecting the information needed to activate a network convergence project. Without a reasonable understanding of the current network environment (topology, traffic patterns, performance), it is virtually impossible to implement a successful convergence project.

This has placed many organizations in the difficult and frustrating situation of recognizing the benefits of migrating videoconferencing over to IP, but not having the ability to make this happen “in real time.” Or, in some cases the organization is ready for convergence in some locations but not in others. This is the enterprise convergence conundrum.



Convergence Considerations

Despite the convergence conundrum, many organizations are in the position to initiate some form of convergence project. To ensure that a converged network can effectively host videoconferencing traffic while not impacting necessary data traffic, organizations should focus on the following areas:

Network Security (Firewalls / DMZ2)

By design, and to protect the data network from intruders, enterprise firewalls typically block the network ports required for videoconferencing between internal and external endpoints. In order to conduct IP video calls with those outside the corporate LAN / WAN, organizations have several options.

Option 1) “H.323-enable” existing firewalls (via software or hardware upgrades) as shown below. Unfortunately, depending upon the network architecture and type of firewall(s) in use, this may be difficult for some enterprises.

Figure 1: Traffic Traversing H.323-“Capable” Firewalls

Option 2) Deploy an H.323 proxy, application layer gateway (ALG), or session border controller (SBC) in the DMZ (as shown below).

Figure 2: Using an H.323 Proxy, ALG, or SBC Solution

2 In this context, the network DMZ (or demilitarized zone) is an area outside the firewall that is accessible to public, Internet traffic. Placing a video system in the DMZ makes it “reachable” to systems on the Internet.



3) Utilize IP-to-ISDN gateways to connect to endpoints outside the firewall as shown below. Note that depending on usage and rates for ISDN long distance calls, this may result in significant monthly fees.

Figure 3: Routing Video Traffic through ISDN Gateways

Option 4) Utilize a third-party, dedicated IP network designed to host videoconferencing traffic. As shown below, this option provides an alternate route for video traffic and thus eliminates any potential burden or security risk on the corporate WAN. Often called an overlay network solution, this option can be used selectively in specific locations to bypass network security, performance, or capacity issues.

Figure 4: Using a Dedicated IP Video Network Overlay Solution

When possible, option 1 tends to be the most cost-effective option as it involves upgrading existing hardware instead of purchasing new equipment or activating a service provider. Option 2 provides secure inter-enterprise conferencing, but because it requires the purchase, deployment, and management of additional network security devices, many organizations seek other alternatives. The ISDN gateway solution in utilized option 3 allows the video traffic to bypass the enterprise firewalls, but routing the traffic over ISDN deprives the organization of the benefits of leveraging its IP network. Finally, for organizations conducting the majority of their videoconferencing internally (without involving external locations), option 4 provides the benefits of migrating video traffic over to IP without impacting the corporate WAN.



The figure below, provided by GlowPoint (the sponsor of this white paper and one of a number of IP videoconferencing service providers), shows a typical deployment of a dedicated IP videoconferencing service provider to host intra- and inter-enterprise videoconferencing. Note also that connecting to the service provider’s network also provides access to the managed ancillary services including video bridging, media servers, and ISDN / PSTN gateways.

Figure 5: A Typical IP Video Network Overlay Deployment

IP Addressing Scheme / Network Addressing Translation (NAT)

Real-time rich media applications, like videoconferencing, can be very demanding on IP networks. As a result, the IP addressing scheme in use can have a significant impact on the performance and usability of the videoconferencing environment. For example, the use of private IP addresses via network address translation (NAT) means that the video system IP addresses may need to be translated (either by the video systems or by firewalls or routers), which adds complexity and potentially latency to the IP video deployment.

Furthermore, some video system directories may require the assignment of static IP addresses to all video systems, which may be an issue for enterprises using DCHP3 throughout the organization.

3 According to Internet.com (http://www.webopedia.com/term/d/dhcp.html), DHCP (which is short for Dynamic Host Configuration Protocol) is a protocol for assigning dynamic IP addresses to devices on a local network. In DHCP environments, a device’s IP address may change each time it reconnects or even while it is connected.



Existing Network Traffic

When analyzing network readiness for video traffic, it is important to understand current traffic patterns on the LAN and WAN. Of specific interest are the type and priority of the traffic traversing the network. For example, certain network paths may be carrying SAP or transaction traffic, while others may be busy with lower priority packets like email, general file transfers, and / or Internet data.

The real-time nature of videoconferencing means that video traffic must traverse the network quickly, and therefore the capability of the network to service additional high-priority traffic must be considered.

Network Quality of Service (QoS) Capabilities

A network designed to host real-time videoconferencing traffic must provide a high level of Quality of Service as follows:

Bandwidth – The network should provide sufficient bandwidth to support the expected number of video calls between various locations plus bandwidth for any other data applications. Note that videoconferencing bandwidth calculations should include a reasonable overhead factor (perhaps 20%), which means that a 384 kbps video call will actually require a total of 460 kbps of bandwidth.

Latency – Best practice calls for a one-way end-to-end latency / network traversal time of less than 150 milliseconds. Higher latency figures will result in an uncomfortable user experience.

Packet Loss – Although most current video systems can compensate for limited packet loss, the packet loss on video-ready networks should be less than 0.5 %.

Jitter – As with packet loss, current video systems have jitter buffers to allow them to recover from limited levels of jitter. Video-ready networks, however, should maintain a jitter level of 50 ms or less.

Prioritization – In networks with even limited amounts of congestion, it may be necessary to prioritize videoconferencing data through the network switches and routers.



Routing Protocols and Routing Redundancy

Network routing protocols determine the path that data packets take along the network between video systems and to/from video infrastructure devices like gatekeepers, ISDN gateways, and video bridges. A typical data network will route traffic randomly as shown below, resulting in varying degrees of performance and latency.

Figure 6: Traffic Routing on a "Typical" Data Network

On the other hand, a well-engineered network routing system will minimize the number of “network hops” (or intermediate connections), and thus minimize the time (delay / latency) it takes for the data to travel from source to destination as shown below.

Mail Server

Video Endpoint

Site ASite BEnterprise Network

Traffic Routing Prioritized --Videoconferencing Latency Is Low

e-Mail Traffic (6 hops)Video Traffic (3 hops)

10 ms

10 ms

50 ms

50 ms

50 ms

310 ms path delay120 ms path delayVideo

Endpoint

e-MailSender

10 ms

60 ms 60 ms

60 ms

60 ms

10 ms

Figure 7: Traffic Routing with Prioritization for Low Latency



In addition, a properly defined network will avoid over-burdening individual network paths, which may cause congestion and packet loss, and will include some degree of redundancy to help the system quickly recover from a component or network failure. Network Elements & Hardware Redundancy

Network device capabilities and settings can significantly detract from a network’s ability to host real-time video traffic. For example, an improperly configured switch could introduce packet loss and QoS problems, which in turn will negatively impact the videoconferencing experience.

Furthermore, in order to support video and other demanding traffic, network elements should be able to provide an appropriate level of reliability and uninterrupted performance. Depending upon the level of reliability that the organization expects from its network (and any services, including video, that ride on that network), devices whose logs show excessive (> 0.5%) packet loss, cyclic redundancy check (or CRC) errors, resets, or other issues should be carefully investigated and possibly upgraded / replaced.

WAN Topology

The general layout of the enterprise WAN can impact the network’s ability to host video traffic. For example, WANs that include data lines from multiple network service providers (NSPs) may not be able to provide end-to-end network management and QoS. In many cases this is due to the lack of QoS marking translation between NSPs, which means that data tagged as high priority (like real-time multimedia traffic) may lose its prioritization status when traversing from one NSP’s network to another. The result is that even internal video calls may suffer from network-related performance problems.

Lack of Ancillary Services

The ability to physically host the video traffic on the network is only one of the elements of a successful IP-based enterprise videoconferencing service. In most cases, internal end users will expect various other service items, capabilities, and infrastructure items to be in place and available to them as needed. In addition, service managers (either IT staff or conferencing resources) will have difficulty effectively managing the environment unless certain management capabilities and support tools are in place.

Items worthy of consideration and investigation include:

Capabilities that enhance ad hoc and personal videoconferencing, for example: o Telephony functions (messaging services, answering services, call forwarding, transfer,

hold) o Reservation-less multipoint bridging (video and audio)

Capabilities that enhance group conferencing, for example: o Centralized web-based scheduling o Automatic call launching and termination o Scheduled multipoint bridging o Meeting archival / streaming / on-demand playback



Support Services o Proactive endpoint monitoring o Usage and performance reporting o 24/7 videoconferencing technical support (available by video, audio, or perhaps IM)

Enterprises seeking to activate some or all of these ancillary services can deploy these services themselves (by purchasing or developing various hardware and software solutions) or activate an external service provider. In recent years a number of providers, including GlowPoint, the sponsor of this white paper, have introduced turnkey videoconferencing services that encompass many of the aforementioned capabilities for a fixed monthly fee.

Figure 8: GlowPoint’s Web Interface for Accessing Video Mail

Readers should not misinterpret this to mean that an organization can not successfully build and manage its own videoconferencing infrastructure. Such a project, however, can be expensive, time-consuming, and resource-intensive. Therefore, Wainhouse Research recommends that organizations carefully evaluate all options, from a cost, benefit, and return standpoint, before making any significant decisions.

Finally, we’d like to point out that this section highlights only a subset of the areas of consideration for organizations planning a convergence initiative. Whenever time and budget / resources allow, Wainhouse Research recommends the activation of a formal network assessment to accurately analyze the network’s level of readiness to effectively host video traffic.



Forward Motion Options

Bearing in mind the considerations outlined in this document, and ideally after having completed a reasonably thorough network assessment, organizations are faced with four top-level options for hosting videoconferencing traffic on their networks. These are: maintain status quo, complete network convergence, a hybrid solution, or the deployment of a dedicated IP video network.

Option 1 – Maintaining Status Quo

Despite the many promises of convergence, and usually due to budgetary or resource limitations, some organizations may determine that running video over IP is not a reachable goal at this time. Therefore, they will elect to continue running their videoconferences over ISDN (or over IP without a strategic plan for guaranteeing consistent performance).

The possible disadvantages of this option are quite clear: high usage costs (per minute), potentially mediocre / inconsistent performance (depending upon the performance of the ISDN network involved), limited management capabilities, and poor scalability. WR has found that many companies remain dissatisfied with the current level of performance and reliability of their videoconferencing environment, which often makes option 1 unacceptable.

Option 2 – Network Convergence

Given the necessary budget and resources, an organization may choose to activate an enterprise-wide convergence initiative. To ensure consistent, end-to-end performance, this will involve upgrading the entire global network to meeting the performance recommendations set forth in this document. Since most WANs were designed to support non-real time (NRT) traffic, the scope of the convergence project typically includes:

Network topology enhancements (upgraded data lines, etc.)

Network hardware upgrades / replacements

Routing protocol updates / changes

Deployment of network and conferencing management / monitoring tools

For organizations that depend upon their visual collaboration, such initiatives may be worthwhile. But for organizations that do not consider videoconferencing a corporate priority, these costs may be difficult to justify.

Option 3 – The Hybrid Solution

Many organizations will find that it may be cost-prohibitive to complete the minimum necessary enhancements to enable the network at some locations to host video traffic. For example, “video-enabling” an office might involve upgrading the existing data connection at a considerable incremental monthly fee. To bypass these convergence-related issues cost-effectively, organizations should consider a selective deployment of a video-ready overlay network.



Figure 9: Bypassing Network Issues Using an Overlay Network

The diagram above shows a hybrid solution involving the selective use of ISDN and an IP overlay network solution to supplement an organization’s existing data network. As shown, the WAN links connecting Sites A and C are “video-capable” while the links to Sites B and D are not. Instead of upgrading the WAN links to sites B and D, this organization chose to deploy an IP overlay network solution for sites A and B (see blue lines above) and to continue using ISDN to connect to site D.

Option 4 – Deploying a Dedicated IP Video Network

Several companies, including GlowPoint, the sponsor of this white paper, offer turnkey video-ready IP-network solutions. Such offerings typically include high-performance QoS network services, video telephony and help desk services, and even “managed” ancillary services (scheduling, bridging, reporting, billing, etc.). In many cases, deploying such a service will allow the end user organization to quickly and cost-effectively activate IP video, without having to upgrade its network to support converged voice, video, and data traffic.

Note that while IP videoconferencing overlay networks are typically used to facilitate intra-enterprise video calls, most also allow communication with external endpoints via service-provider managed gateways (ISDN / Public Internet) and by allowing external endpoints to register to their gatekeepers.

Organizations seeking to enjoy the benefits of running video over IP quickly and without the cost and workload of a convergence initiative should consider the total or selective deployment of an IP video service. Due to the complexities involved in firewall traversal, network routing and addressing, and the high cost of network hardware and data line upgrades, Wainhouse Research expects to see many organizations deploy hybrid convergence / dedicated IP video network solutions in the near future. In some cases the deployment will be for long-term, and in other cases it may serve as an interim measure to allow the enterprise to formally initiate and complete its own convergence initiative.



Conclusion

The benefits of a converged voice, video, and data network have compelled organizations to add enterprise-wide convergence to their long-term strategic network plans. Although current conditions have blocked many organizations from achieving global convergence in real time, the typical enterprise can improve the performance and cost-effectiveness of its videoconferencing by implementing one or more interim initiatives including:

Migrating a select portion of their video traffic from ISDN to IP

Implementing limited network enhancements to solve specific issues or problems

Utilizing third-party overlay networks to circumvent problematic network areas and/or gain access to “managed” ancillary services (help desks, video telephony features, bridging, monitoring, scheduling, etc.) without the need for capital investments or additional resources.

In short, organizations that are currently unable to include video conferencing in an enterprise-wide convergence project may still be able to enjoy significant video service performance enhancements and cost-savings by selectively enhancing their networks and utilizing third-party services.



About Wainhouse Research

Wainhouse Research (http://www.wainhouse.com) is an independent market research firm that focuses on critical issues in rich media communications, videoconferencing, teleconferencing, and streaming media. The company conducts multi-client and custom research studies, consults with end users on key implementation issues, publishes white papers and market statistics, and delivers public and private seminars as well as speaker presentations at industry group meetings. Wainhouse Research publishes Conferencing Markets & Strategies, a three-volume study that details the current market trends and major vendor strategies in the multimedia networking infrastructure, endpoints, and services markets, as well as a variety of segment reports, the free newsletter, The Wainhouse Research Bulletin, and the PLATINUM (www.wrplatinum.com) content website.

About the Author

Ira M. Weinstein is a Senior Analyst and Consultant at Wainhouse Research, and a 14-year veteran of the conferencing, collaboration and audio-visual industries. Prior to joining Wainhouse Research, Ira was the VP of Marketing and Business Development at IVCi, managed a technology consulting company, and ran the global conferencing department for a Fortune 50 investment bank. Ira’s current focus includes IP video conferencing, network service providers, global management systems, scheduling and automation platforms, ROI and technology justification programs, and audio-visual integration. Mr. Weinstein holds a B.S. in Engineering from Lehigh University and is currently pursuing an MBA in Management and Marketing. He can be reached at [email protected].

About GlowPoint

Glowpoint, Inc. (NASDAQ: GLOW) is the world’s leading broadcast quality, IP-based video communications service provider. GlowPoint operates a video communications service featuring broadcast quality images with telephone-like reliability, features, and ease-of-use, and is a member of the Cisco Powered Network Program and COVAD Partner Program. The GlowPoint network spans three continents and carries on average over 20,000 video calls per month worldwide. Since the network was introduced in 2000, GlowPoint has carried over 23 million IP video minutes. GlowPoint is headquartered in Hillside, New Jersey.

To learn more about GlowPoint, visit us at www.glowpoint.com.



mailto:[email protected]

http://www.nasdaq.com/scripts/redir.asp?symbol=GLOW&page=quotes

http://www.glowpoint.com/

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Real-World IP Network Convergence for Conferencing