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Network Services

Internet Protocol Television (IPTV)

The Academic Television Network (ATN) is the TV network that is at end-of-life. Our intent is to keep the Residential Television Network (RTN) operational. We have no plans to put the RTN programs on IPTV.

Our initial plan with IPTV is to carry the same 11 television channels that were on the ATN.

Our cost model is no charge for the 11 channels. We see this as a backbone service. At present, there is no support for authorization or billing for IPTV.

Cisco supports their client only on Windows. There is a third party freeware application called MacTV that works on the Mac. IPTV interoperates with the mBone tools, so IPTV channels can be viewed on UNIX/Linux platforms. Cisco Doesn't support the Mac or UNIX/Linux platforms.

In addition, the Apple QuickTime client can view IPTV programs on Windows or Mac platforms.

One feature of IPTV that is not present in the RTN is on-demand video. Programs like Tech Partners presentations or training video can be made available on IPTV, and watched at the users' convenience. We don't see IPTV as a monolithic system with all material centrally stored and administered. It is possible for departments to have their own IPTV encoders. The main Content Manager could manage those encoders or the department could manage them independently.

By the way, DoIT also offers services for users of QuickTime, Real Media and Windows Media. These won't go away. The new network will make these technologies work better, whether DoIT is providing the service or your department is providing the service.

The IPTV client can also see television programs from the mBone (the multicast backbone on the Internet). Using this feature, it is possible to watch the Research Channel from Research TV at the University of Washington, or NASA Television, or the proceedings of the Internet Engineering Task Force, or television programs from anywhere in the world where there is an Internet connection. It is also possible to make one or more campus-originated channels available to the outside world with this technology. This potential for global scope is one of the big differences between cable television and IPTV. Another difference is the change from central control of program sources to distributed control of programs. Your department won't need to get DoIT's permission to provide a channel to others.

The 11 channels from Charter will only be available on the Madison campus (we will use locally-scoped multicast addresses so that it will not be possible to view those programs outside of our network). This is a requirement of Charter.

DSL and cable modem providers do not support multicast. (Dial-up Internet service providers don't support multicast either, but they don't have sufficient bandwidth for television, so the multicast issue is moot in this case.) As a result, IPTV multicast channels will not be available over DSL or cable modems. On-demand programs use unicast technology, so it is possible to view on-demand programs over DSL or cable modem technology if the bandwidth is available (I have tested this on Charter cable modems at home, and it works).

We are working on finding a vendor for a television appliance, a device like a set-top box for viewing IPTV on conventional television sets. This market is in flux right now. Most of the vendors in this market segment want to appeal to the consumer/home market, and they don't seem interested in the institutional/educational market (they are still seeing dollar signs in the consumer market). (With the dot bomb last year, this market has taken a pounding.)

The timeframe for IPTV is indefinite, but dependent on the Twenty First Century Network. There are currently 4 IPTV channels working, but we don't want IPTV to be used until the XXICN is operational in a building. Multicast is a technology with its own set of issues to deal with, and can put a lot of stress on older networks. Multicast only works well when the network is all switched (no hubs), and only on switches that support multicast pruning. (In such a network, only the person viewing a multicast stream sees the traffic. Without pruning, the multicast traffic floods the network, eating up available bandwidth. In tests on the DoIT internal network, multicast saturated several wireless access points, making them unusable.) Once the XXICN is operational in a building or department, we will coordinate with your network support people before we enable it on your network. As we get more experience and confidence, and when it becomes usable in a reasonable number of locations, we'll publicize the technology more openly.

There are some shortcomings in IPTV. The scaling of the Content Manager is limited. For example, it is not possible to make an Internet2-wide content manager, which has links to all the Content Managers in all the Internet2-connected institutions. There is no good way to limit viewing to a select group of viewers (for example, only students in anatomy 711 or to people who pay a fee to view a conference). We are working with Cisco to extend the capabilities of IPTV.

The scope of IPTV is limited to the Madison campus. While the technology will work on WiscNet or Internet2, we have made the decision that we won't support it beyond the campus border. Support for off-campus UW-Madison departments or facilities is on a case-by-case basis, depending on the type of equipment they use and the type of connection to the campus network.

The support model for IPTV is best-effort. We can't, for example, guarantee that IPTV will work on the existing (pre-XXICN) network. I am sure we will get requests by department managers to block IPTV for entire departments. If departments manage their own LAN, we can't troubleshoot multicast or IPTV without their cooperation. Support for multicast is interdependent with many other routing policy issues. If your department has custom or unusual router configurations, it will take time and consultation to determine the best way to implement multicast. Firewalls will need to be programmed for multicast, and may not support multicast.

Questions or comments about IPTV can be directed to David Devereax-Weber (dave@cable.doit.wisc.edu).