table of contents

Executive Summary

In July 2001, the Indiana Higher Education Telecommunication System (IHETS) Integrated Technologies Committee (ITC) formed an IP Video Task Force (IPVTF) to evaluate two-way interactive video over IP networks using the H.323 protocol and to recommend to the Indiana Telecommunications Network (ITN) various hardware/software and policy components required for implementing H.323 IP video.

This report will help network designers, technical coordinators, faculty, students, and administrators understand the basic functioning of H.323-based video conferencing. The section dealing with codecs should provide schools, libraries, and other institutions with guidance on the purchase of equipment.

Task Force recommendations will provide direction for ITN to implement a state-of-the-art H.323 video conferencing environment that is robust and scalable for the state of Indiana.

The topics reviewed and discussed by the IPVTF include:

• H.323 Codecs (endpoint terminal equipment)
• Multipoint Conference Units (MCU)
• Gatekeepers
• Gateways
• Dial Plan Development
• Directory Services
• Quality of Service (QoS)

The H.323 standard covers four fundamental hardware elements of a complete network system: terminals (also called codecs), gatekeepers, gateways, and MCUs. Figure 1 presents a sample implementation of these four elements, also demonstrating how the IP technology will interface with existing ISDN and ATM technology. Dial plans and directory services are policy and support mechanisms used to make an H.323 network easier to use. Finally, QoS is a function of the underlying IP network, transparent to the end-user while it is working but immediately evident if it fails.

Many education institutions are already using IP-based video conferencing. Indiana University, Purdue University, and Ball State University are delivering instruction via IP video conferencing, while libraries and K-12 institutions are using the technology for administrative video conferencing. It is therefore important that ITN provide a consistent service across the shared network resource soon to avoid later having to work around multiple competing investments in equipment and policy components.

Because this technology is rapidly evolving and changing, the actual implementation of IP video on ITN will undoubtedly evolve along with the technology. Sections of this document should, however, continue to be useful reference tools for ITN customers and others considering investments in IP video.

Figure 1

Summary Recommendations

Listed below are the recommendations of the IPVTF. Please see each specific section for more detail.

Video conferencing Endpoints (Codec)

Recommendation: The IP Video Task Force recommends that ITN support products from the following manufacturers. It is also recommended that ITN customers purchase from these choices in order to have access to a larger knowledge base for troubleshooting.

Polycom:

Appliance Based Room Systems

• Viewstation FX
• Viewstation VS4000
• Viewstation MP

Appliance Based Set-Top Systems

• Viewstation H.323
• Viewstation SP128
• Viewstation SP384
• Viewstation 128

PC Based Desktop System

• ViaVideo

VCON:

PC Based Room Systems

• Media Connect 8000 model 3, MC8000

PC Based Desktop System

• ViGO
• Escort
• Cruiser

Multipoint Control Unit (Bridge)

Recommendation: The IPVTF recommends the ACCORD MGC-100 MCU for the following reasons:

• It supports H.323 (IP), H.321 (ATM), and H.320 (ISDN) protocols.
• Participants in the tests rated Accord highest for audio and video quality.
• Implementation of the Accord will allow for unified scheduling across IP and ATM video. Other bridges require third-party software to achieve this.
• The Accord MCU was designed for carrier or service providers.
• The Accord provides for more continuous-presence options.
• Continuous presence on the Accord is symmetric. For example, four 384 kbps calls input are output as one 384 kbps call. On other MCUs, four 384 kbps calls input are output as one 1.344 Mbps call. This would use the entire bandwidth of a T1 link and significantly increase the customer’s cost for video conferencing.
• The Accord has more functionality features than the other MCUs, allowing for greater flexibility in the provision of services.

Gatekeeper

Recommendation: The IPVTF recommends that ITN adopt a hierarchical gatekeeper plan consisting of a “Main Directory” gatekeeper, “Zone” gatekeepers, and “Institutional” gatekeepers.

Gateway

Recommendation: The IPVTF recommends the purchase of a Radvision L2W-323 PRI gateway to support inbound ISDN-to-ITN traffic.

Dial Plan

Recommendations: The IPVTF recommends the following:

• The dial plan will take the form of: E[*T]ZZZNNNNNNN; where E = Exit zone; *T = Technology prefix; Z = Area code; and N = 7 digit dialing extension number.
• The dial plan will support ISDN codecs that have specific circuit restrictions through the use of Technology prefixes.
• A PRI be purchased to support “ISDN off net” to “IP on net” Point-to-Point calls.
• An ISDN to IP gateway be purchased to support “ISDN off net” to “IP on net” Point-to-Point calls.

Directory Services

Recommendation: The IPVTF recommends that First Virtual Communications, Inc., Click to MeetTM be used to provide directory services.

Quality of Service (QoS)

Recommendation: The IPVTF recommends that the ITN provide QoS throughout the network up to the point of demarcation for ITN, the LAN interface on the router. At this point, packets will continue to be “prioritized;” however, the customer to determine how to act upon those packets.