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IP/TV brings movie-quality video to the user's computer, eliminating the need for dedicated video cabling, monitors, or special viewing rooms. IP/TV Version 3.0 supports a wide variety of audio/video formats including MPEG1, MPEG2, MPEG4, and H.261.
IP/TV is used in applications such as broadcast TV to the desktop, video on demand, computer-based training, distance learning, corporate communications, manufacturing process monitoring, and surveillance systems.
To view a seven-minute video that describes IP/TV's capabilities, click Introduction Video on the Cisco IP/TV Installer CD.
IP/TV consists of following three separate components:
IP/TV Viewer gets program information from the IP/TV Content Manager, and displays programs served by IP/TV Server or other servers. It can also display programs multicast from the Internet's Multicast Backbone (MBone) or from other servers that transmit in MBone-compatible format.
IP/TV Viewer can run as a standalone application, a helper application activated by a Web browser, or a browser plug-in. It runs on Windows 95, Windows 98, and Windows NT 4.0.
Refer to the IP/TV Viewer User Guide for information on how to install and use the IP/TV Viewer.
IP/TV Content Manager runs on Windows NT 4.0, and can be accessed from Netscape 4.05 or 4.5x, or Microsoft Internet Explorer 4.x or 5.0. The browser must have support for Java and JavaScript enabled.
This guide provides information on how to create scheduled and on-demand programs. Refer to the IP/TV Administration and Configuration Guide for information on how to install, configure, and administer the IP/TV Content Manager.
The same server can be used for live encoding with a video capture card and for serving prerecorded files.
Refer to the IP/TV Administration and Configuration Guide for information on how to install, configure, and administer IP/TV Server.
You can use IP/TV for the broadcast of scheduled live or prerecorded programs, on-demand programs, or a combination of the two.
You can use a given server to broadcast both scheduled and on-demand programs.
Figure 1-1 shows the interactions between IP/TV components in the case of scheduled programs. Note that although the IP/TV Viewer receives program descriptions only from the IP/TV Content Manager, the programs are sent to IP/TV Viewer from the various media servers. The media servers may be IP/TV Servers, MBone servers, or other servers that run IP/TV-compatible MBone tools.
IP/TV Components --- Scheduled Programs
Figure 1-2 shows the interactions between these components in the case of on-demand programs. The IP/TV Content Manager manages a group (cluster) of servers that together form a virtual machine, with an integrated database to keep track of program information. Clustering allows the IP/TV Content Manager to balance the server load by routing a user's program request to the least busy server.
IP/TV Release 3.0 introduces the following new features:
The IP/TV Content Manager can manage both scheduled and on-demand programs. The uses, advantages, and limitations of scheduled and on-demand programs are discussed in the sections that follow.
Scheduled programs are available to viewers at times defined by the IP/TV Content Manager, and are delivered by one multicast data stream per media type (video, audio, Web Presenter, or SlideCast). Scheduled programs can reach unlimited numbers of viewers simultaneously without overloading the network (see the Introduction chapter of the IP/TV Administration and Configuration Guide).
Scheduled programs can be live content sent to viewers in real time, or prerecorded content that can be played repeatedly at scheduled times. Typical uses of scheduled programs include employee communications, group training, and distance learning.
In the IP/TV Content Manager, you define a list of scheduled programs and assign them to one or more specified servers. The list of programs is automatically sent to IP/TV Viewer, and the programs can be watched by users at the scheduled time.
When defining scheduled programs, it is important to understand the relationship between programs and channels. In the IP/TV context, channels and programs are nearly identical to their network television equivalents, but there are a few differences. Understanding these differences will help you create the best model for your organization and manage IP/TV scheduled programming most effectively.
On network television, a channel carries either a single, continuous program (such as a 24-hour news channel) or a series of noncontinuous, back-to-back programs. Programs cannot exist without channels. All programs must be carried by a channel in order to be viewable. To view a program, the user tunes to its channel. The channel itself constitutes the address of all programs on that channel.
On IP/TV, a channel can carry either a single, continuous program, a series of noncontinuous, back-to-back programs, or both.
A noncontinuous program can overlap a continuous program. It is defined as a separate entity that can be tuned in by the user.
An example of a continuous program that has a noncontinuous program overlapping it is a 24-hour news service. The news program is always on, and users can tune in whenever they want to get a news update. Suppose, though, that the financial news is always discussed for half an hour starting at 3:00 p.m., and some users want to subscribe only to the financial news so that IP/TV automatically launches the program for them. You can define a noncontinuous program that begins at 3:00 p.m. and runs for 30 minutes. The noncontinuous program is a subset of the 24-hour news program, and overlaps it for that 30-minute interval. This is a mechanism to allow the user to subscribe to a small portion of the continuous program.
A channel constitutes a template for programs. The programs on that channel share the channel's address and a variety of common characteristics such as passwords.
Unlike network television, an IP/TV program need not be assigned to a channel. It can exist independently. In this case, the program simply has its own address. Thus, if you prefer, you can omit the channel mechanism altogether. However, a channel is useful if you want to create programs with similar characteristics.
OnDemand programs are available to individual users to watch at the time of their choosing. As multiple requests for an on-demand program require more network bandwidth than for a scheduled program (see the "Unicast Traffic" section in the Introduction chapter of the IP/TV Administration and Configuration Guide), we recommend that you use OnDemand for programs that are accessed less frequently, such as individualized corporate training and video archives.
The IP/TV Content Manager manages a cluster of servers that together form one larger server, with an integrated database to keep track of server and program information. The IP/TV Content Manager automatically collects a list of available media files from the cluster, and, using the Cisco FTP Server, can also schedule distribution of files from one server to another or from an outside source to one or more of the servers.
The administrator then defines these files as programs in the IP/TV Content Manager, using a hierarchical tree of program categories. A top level category can contain subcategories, which you navigate to by clicking links. This allows you to manage and make available a large library of programs.
One or more subnets can be defined as a Proximity Group, and one or more Proximity Groups are associated with a given server cluster. This allows the administrator to localize network traffic by ensuring that IP/TV Viewers receive OnDemand programs only from their local cluster.
The IP/TV Content Manager distributes a list of available on-demand programs to IP/TV Viewers. When a user requests to watch a program, the IP/TV Content Manager uses information from the database to assign the least busy server in the cluster to meet the request, then directs the IP/TV Viewer to that server. If one of the servers fails, or needs to be taken out of service, the IP/TV Content Manager balances the request load among the remaining servers.
Channels do not apply to OnDemand programs.
Posted: Thu Oct 28 16:38:00 PDT 1999
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